PAST AP FRQ's

2013 2012 2011 2010 2009 2008
2007 2006 2005 2004 2003 2002
2001 2000 1999      

CELLS DNA/RNA/PROTEINS ECOLOGY ENZYMES EVOLUTION GENETICS
WATER METABOLISM MITOSIS/MEIOSIS MOLECULES PHOTOSYNTHESIS RESPIRATION

SIGNALING

TRANSPORT PLANTS REGULATION
HOMEOSTASIS  
LABS GRAPH READING
BODY SYSTEMS STRUCTURE & FUNCTION DNA  SIGNALING     

2013

2013 All questions       Scoring quidelines       Sample Responses Q1


2013 #1
An investigation of fruit-fly behavior, a covered choice chamber is used to test whether the spatial distribution of flies is affected by the presence of a substance placed at one end of the chamber.  To test the flies' preference for glucose, 60 flies are introduced into the middle of the choice chamber at the insertion point indicated by the arrow in the figure above. A cotton ball soaked with a 10% glucose solution is placed a tone end of the chamber, and a dry cotton ball with no solution is placed at the other end. The positions of flies are observed and recorded every minute for 10 minutes.

a) Predict the distribution of flies in the chamber after 10 minutes and JUSTIFY your prediction.

b) PROPOSE ONE specific improvement to each of the following parts of the experimental design and EXPLAIN how the modification will affect the experiment.

~ Experimental control
~ Experimental factors

c) The experiment described above is repeated with ripe bananas at one end and unripe bananas at the other end. Once again the positions of the flies are observed every minute for 10 minutes.  The positions of flies after 1 min and after 10 minutes are shown in the table below.



 
Perform a chi-square test on the data for the 10-minute time point in the banana experiment.  SPECIFY the null hypothesis that you are testing and enter the values from you calculations in the table below.

d) EXPLAIN whether your hypothesis is supported by the chi-square test and JUSTIFY your explanation.

e) Briefly PROPOSE a model that describes how environmental cues affect the behavior of the flies in the choice chamber.

 

2013 All questions       Scoring quidelines       Sample Responses Q2
2013 #2

 

An absorption spectrum indicates the relative amount of light absorbed across a range of wavelengths. The graphs above represent the absorption spectra of individual pigments isolated from two different organisms.  One of the pigments is chlorophyll a, commonly found in green plants. The other pigment is bacteriorhodopsin,  commonly found in purple photosynthetic bacteria.  The table above shows approximate ranges of wavelengths of different colors in the visible light spectrum.

a) IDENTIFY the pigment (chlorophyll a or bacteriorhodopsin) used to generate the absorption spectrum in each of the graphs above. EXPLAIN and JUSTIFY your answer.

b) In an experiment, identical organisms containing the pigment from Grph II as the predominant light capturing pigment are separated into three groups. The organisms in each group are illuminated with light from a single wavelength. (650 nm for the first group, 550 nm for the second group, 420 nm for the third group). The three light sources are of equal intensity, and all organisms are illuminated for equal lengths of time.  PREDICT the relative rate of photosynthesis in each of the three groups.  JUSTIFY your predictions.

c) Bacteriorhodopsin has been found in aquatic organisms whose ancestors existed before the ancestors of plants evolved in the same environment. PROPOSE a possible evolutionary history of plants that could have resulted in a predominant photosynthetic system that uses only some of the colors of the visible light spectrum.


2013 All questions       Scoring quidelines       Sample Responses Q3
2013 #3 . Fossils of lobe-finned fishes, which are ancestors of amphibians, are found in rocks that are at least 380 million years old. Fossils of the oldest amphibian-like vertebrate animals with true legs and lungs are found in rocks that are approximately 363 million years old.

Three samples of rocks are available that might contain fossils of a transitional  species between lobe-finned fishes and amphibians: one rock sample that is 350 million years old, one that is 370 million years old, and one that is 390 million years old.

a) SELECT the most appropriate sample of rocks in which to search for a transitional species between lobe-finned fishes and amphibians. JUSTIFY your selection.

b) DESCRIBE TWO pieces of evidence provided by fossils of a transitional species that would support a hypothesis that amphibians evolved from lobe-finned fish.

2013 All questions       Scoring quidelines       Sample Responses Q4

#4. Matter continually cycles through an ecosystem. A simplified carbon cycle is  depicted below.

a) IDENTIFY the key metabolic process for step I and the key metabolic process for step II and briefly EXPLAIN how each process promotes movement of carbon through the cycle.  For each process, your explanation should focus on the role of energy in the movement of carbon..
IDENTIFY an organism that carries out both processes.

2013 All questions       Scoring quidelines       Sample Responses Q5

The table below shows the amino acid sequence of the carboxyl-terminal segment of a conserved polypeptide from four different, but related, species. Each amino acid is represented by a three-letter abbreviation, and the amino acid residues in the polypeptide chains are numbered from the amino end to the carboxyl end.  Empty cells indicate no amino acid is present.

a) Assuming that species I is the ancestral species of the group, EXPLAIN the most likely genetic change that produced the polypeptide in species III.

b) PREDICT the effects of the mutation on the structure and function of the resulting protein in species IV. JUSTIFY your prediction.

2013 All questions       Scoring quidelines       Sample Responses Q6

#6. The following data were collected by observing subcellular structures of three different types of eukaryotic cells.

 

Based on the analysis of the data, IDENTIFY a likely primary function of each cell type and EXPLAIN how the data support the identification.

 

2012  

2012 All  Questions      Scoring Guidelines        Score Distributions            Sample Responses Q1

2012 #1
The ability to reproduce is a characteristic of life.
     (a) Describe the process of embryological development in a typical vertebrate embryo, beginning with a fertilized
                 egg and ending with the development of three tissue layers.
      (b) Identify the developmental origin of TWO of the following tissues in vertebrates:
              -
central nervous system
              -
digestive system
              -
muscle
      (c)
Identify and explain THREE differences between the embryological development of protostomes and the
             
embryological development of deuterostomes.
      (d) Explain TWO unique properties of human embryonic stem cells that distinguish them from other human
             cell types.
Describe a current medical application of human stem cell research.

2012 All Questions                 Scoring Guidelines               Score Distributions         Sample Responses Q2

2012 #2.


An agricultural biologist was evaluating two newly developed varieties of wheat as potential crops. In an
experiment, seedlings were germinated on moist paper towels at 20ΊC for 48 hours. Oxygen consumption of the
two-day-old seedlings was measured at different temperatures. The data are shown in the graph below.
      (a)
Calculate the rates of oxygen consumption in mL/min for each variety of wheat at 7°C and at 17°C.
            Show
your work (including your setup and calculation).
      (b)
Explain the relationship between metabolism and oxygen consumption. Discuss the effect of temperature on
              metabolism for each variety of seedlings.
      (c) In a second experiment, variety A seedlings at both temperatures were treated with a chemical that prevents
              NADH from being oxidized to NAD
+. Predict the most likely effect of the chemical on metabolism and
             oxygen consumption of the treated seedlings.
Explain your prediction




2012 All Questions             Scoring Guidelines          Score Distributions              Sample Responses Q3 

2012 #3
Information flow in cells can be regulated by various mechanisms.
      
(a) Describe the role of THREE of the following in the regulation of protein synthesis:
          
􀁸 RNA splicing
          
􀁸 repressor proteins
          
􀁸 methylation
          
􀁸 siRNA
     (b) Information flow can be altered by mutation.
Describe THREE different types of mutations and their effect
             
on protein synthesis.
     (c) Identify TWO environmental factors that increase the mutation rate in an organism, and discuss their effec
           
on the genome of the organism.
       (d) Epigenetics is the study of heritable changes in the phenotype caused by mechanisms other than changes in
            the DNA sequence. Describe ONE example of epigenetic inheritance.

2012 All Questions                         Scoring Guidelines                  Score Distributions            Sample Responses Q4

2012 #4.
The element carbon is contained in all organic compounds.
    
(a) Discuss the role of photosynthesis and cellular respiration in carbon cycling in the biosphere.
    (b) For THREE of the following,
predict and explain the effect on the carbon cycle if:
           
􀁸􀀃 decomposers were absent
           
􀁸􀀃 deforestation occurred
           
􀁸􀀃 volcanic dust accumulated in the atmosphere
           
􀁸􀀃 the average ocean temperature increased
    (c)
Explain how increased CO2 in the atmosphere results in greater acidification of oceans and describe the
          effect on marine organisms.
Include in your discussion TWO examples of how human activity can increase
          atmospheric CO
2.


 
2011

2011 All Questions           Scoring Guidelines               Sample Responses Q1
2011 #1
During an investigation of a freshwater lake, an AP Biology student discovers a previously unknown microscopic organism.
Further study shows that the unicellular organism is eukaryotic.
   (a) Identify FOUR organelles that should be present in the eukaryotic organism and describe
the function of each organelle.
   (b) Prokaryotic cells lack membrane-bound organelles found in eukaryotes. However, prokaryotes must perform many of the same functions as eukaryotes.    
For THREE of the organelles identified in part (a),
explain how prokaryotic cells carry out the associated functions.
  (c) According to the endosymbiotic theory, some organelles are believed to have evolved through a symbiotic relationship between eukaryotic and
        prokaryotic cells.
Describe THREE observations that support the endosymbiotic theory.

2011 All Questions           Scoring Guidelines              Sample Responses Q2

2011 #2
Organisms utilize a diversity of methods to obtain proper nutrition.
a) Some organisms digest food intracellularly, while others digest food extracellularly.
    - Identify ONE nonvertebrate organisms that digests food intracellularly and describe the process.
    -
Identify ONE nonvertebrate organisms that digests food extracellularly and describe the process.

b) DESCRIBE TWO structural features of the human stomach and/or small intestine. For  each explain how the structure relates to function.
c) Plants have a variety of mechanisms for obtaining  nutrients. DESCRIBE TWO plant structures and explain how each structure is utilized in nutrient uptake.

2011 All Questions           Scoring Guidelines           Sample Responses Q3

2011 #3
 Reproduction can be either asexual or sexual.
(a) Using a specific example,
describe how organisms can reproduce asexually. Discuss TWO evolutionary advantages of asexual reproduction.
(b)
Identify THREE ways that sexual reproduction increases genetic variability. For each, explain how it increases genetic diversity among the offspring.
(c)
Discuss TWO prezygotic isolating mechanisms that prevent hybridization between two species. Include in your discussion an example of each mechanism.

2011 All Questions           Scoring Guidelines          Sample Responses Q4

2011 #4.
The regulation of transpiration is an important homeostatic mechanism in plants.

(a) Under controlled conditions, a transpiration experiment was conducted using two plant species. The data collected are shown in the figure below. Using the data from the experiment, calculate the rate of transpiration for species A and species B between the times of 5 and 15 minutes (show your work).

Summarize the difference between the two transpiration rates.

WATER LOSS VERSUS TIME FOR TWO PLANT SPECIES

(b) Identify and explain THREE different structural or physiological adaptations that could account for the different transpiration rates of species A and B.
(c) Water potential (
Ψ) is described by the following formulas.

Discuss the variables in both formulas and how they affect water potential.

 


Questions

Scoring

Samples and Commentary

Score Distributions



 

2011 B All Questions             Scoring Guidelines          Sample Responses Q1

2011 B #1. The cell cycle is fundamental to the reproduction of eukaryotic cells.

           (a) Describe
the phases of the cell cycle.
           (b) Explain
the role of THREE of the following in mitosis or cytokinesis.
            -Kinetochores
            -Microtubules
            -Motor proteins
            -Actin filaments

          (c) Describe
how the cell cycle is regulated and discuss ONE consequence of abnormal regulation,

2011 B All Questions             Scoring Guidelines         Sample Responses Q2

2011B
#2. Ecological succession describes the pattern of changes in communities over time. The graph below shows changes in plant diversity following the abandonment of an agricultural field in a temperate biome.

(a) Discuss the differences in plant diversity shown in the graph and explain how the changes affect the animal species composition between years 0 and 120.(b) Identify TWO biotic and TWO abiotic factors and discuss how each could influence the pattern of ecological succession.
(c)
Design a controlled experiment to determine how the diversity of plant species in a newly abandoned field would be affected by large herbivores.

2011 B All Questions             Scoring Guidelines         Sample Responses Q3

2011B
3. Invasive species, such as red fire ants, introduced into an ecosystem often threaten native plants and animals.

(a) Describe THREE different factors that contribute to the success of invasive species in an ecosystem.

(b) Discuss THREE ways that an invasive species can affect its new ecosystem.



(c
) The map indicates the spread of the red fire ant after its initial entrance into the United States at the port of Mobile, Alabama, in the 1930s.
      
Discuss TWO environmental factors that might have determined the pattern of fire ant invasion.

(d) Discuss TWO possible methods of eradicating or slowing the spread of these ants, including the environmental consequences of each method.

2011 B All Questions             Scoring Guidelines           Sample Responses Q4

2011B #4
Phylogeny reflects the evolutionary history of organisms.
a) DISCUSS TWO mechanisms of speciation that lead to the development of separate species from a common ancestor.
b) EXPLAIN THREE methods that have been used to investigate the  phylogeny of organisms. DESCRIBE a strength or weakness of each method.
c) The two phylogenetic trees represent the relationship of whales to six other mammals.  All of the organisms shown have a pulley-shaped astragalus bond in
    the ankle except for the whale.
    - For each tree, DESCRIBE a monophyletic group, the closest relative to the  whale, and the point at which the pulley astragalus was lost or gained.
    - Based on the principle of parsimony (the simplest explanation is the best) and the genomic information in the table shown, IDENTIGY which tree is the best
        representation of the evolutionary relationship of these animals , and JUSTIFY your answer.

 

2010

2010 All Questions         Scoring Guidelines          Sample Responses Q1


2010 #1
Homeostatic maintenance of optimal blood glucose levels has been intensively studied in vertebrate organisms.
a) Pancreatic hormones regulate blood glucose levels.  IDENTIFY TWO pancreatic hormones and DESCRIBE the effect of each hormone on blood glucose levels.
b) For ONE of the hormones you identified in (a), IDENTIFY ONE target cell and DISCUSS the mechanism by which the hormone can alter activity in that target cell.  INCLUDE in your discussion a description of reception, cellular transduction, and response.
c) COMPARE the cell-signaling mechanisms of steroid hormones and protein hormones.

2010 All Questions         Scoring Guidelines          Sample Responses Q2

2010 #2
An experiment was conducted to measure the reaction rate of the human salivary enzyme 
α-amylase.  Ten mL of a concentrated starch solution and 1.0 mL of α-amylase solution were placed in a test tube. The test tube was inverted several times to mix the solution and then incubated at 25 °C.  The amount of product (maltose) present was measured every 10 minutes for an hour.  The results are given in the table below.

a) GRAPH the data on the axes provided and CALCULATE the rate of the reaction for the time period 0 to 30 minutes.
b) EXPLAIN why a change in the reaction rate was observed after 30 minutes.
c) DRAW and LABEL another line on the graph to predict the results if the concentration of an α-amylase was doubled.  EXPLAIN your predicted results.
d) IDENTIFY TWO environmental factors that can change the rate of an enzyme-mediated reaction.  DISCUSS how each of those two factors would affect the reaction rate of an enzyme.

2010 All Questions         Scoring Guidelines         Sample Responses Q3

2010#3
A new species of fly was discovered on an island in the South Pacific. Several different crosses were performed, each using 100 females and 100 males. The phenotypes of the parents and resulting offspring were recorded.
   
Cross 1: True-breeding bronze-eyed males were crossed with true-breeding red-eyed females. All of the F
1 offspring  had bronze eyes. F1 flies were crossed, and the date for the resulting F2 flies are given in the table below.

F2 Phenotype   Male  Female 
Bronze eyes  3,720 3,800 
Stunted wings 1,260  1,320

Cross II: True-breeding normal-winged males were crossed with true-breeding stunted-winged females. All the F1 offspring had stunted-wings. F1 flies

F2 Phenotype   Male  Female 
Normal wings  1,160  1,320 
Stunted wings 3,600 3,820 

Cross III: 

F2 Phenotype   Male  Female 
Bronze eyes , stunted wings 2,360 2,220
Bronze eyes, normal wings  220 300 
Red eyes, stunted wings  260  220 
Red eyes, normal wings  2,240  2,180 

a) What conclusions can be drawn from Cross I and Cross II? EXPLAIN how the data support your conclusion for each cross.
b) What conclusions can be drawn from Cross III? EXPLAIN how the data support your conclusions.
c) IDENTIFY and DISCUSS TWO different factors that would affect whether the island's fly population is in Hardy-Weinberg equilibrium for the traits above.




2010 All Questions        
Scoring Guidelines          Sample Responses Q4

 

2010#4
The diagram above shows the succession of communities from annual plants to hardwood trees in a specific area over a period of time.
a) DISCUSS the expected changes in biodiversity as the stages of succession progress as shown in the diagram above.
b) DESCRIBE and EXPLAIN THREE changes in abiotic conditions over time that lead to the succession, as show in the diagram above.
c) For each of the following disturbances, DISCUSS the immediate and long-term effects on ecosystem succession.
           (i) A volcano erupts, covering a 10-square-kilometer portion of a mature forest with lava.
           (ii) A 10-square-kilometer portion of a mature forest is clear-cut.

2010 B All Questions          Scoring Guidelines            Sample Responses Q1


2010B #1



Biological molecules can be separated by using chromatographic techniques. 
The digram above shows the separation of several spinach leaf pigments by paper chromatography.
Using the diagram above
   a) EXPLAIN how paper chromatography can be used to separate pigments based on their chemical and physical properties.
   b) DISCUSS the role of pigments both in capturing light energy and in converting it to the chemical energy of  ATP and NADPH.
   c) Use the rule shown above to DETERMINE the Rf value of xanthophyll. SHOW your calculations.

2010 B All Questions          Scoring Guidelines        Sample Responses Q2

2010B#2
Certain genetic conditions, such as sickle cells anemia, result from single base-pair mutations in DNA.
   a) EXPLAIN, how a single base-pair mutant in DNA can alter the structure and in, some cases the function of a protein.
   b) EXPLAIN, using a specific example, the potential consequences of the production  of a mutant protein to the structure and function of the cells of an
            organism.
   c) DESCRIBE how the frequency of an allele coding for a mutant protein may increase in a population over time.

2010 B All Questions          Scoring Guidelines         Sample Responses Q3

2010B#3
Bacteria play central biological roles.
   a) Bacteria may act as
       - producers
      - parasites
      - mutualistic symbionts
      - decomposers
Select THREE of the ecological roles above. For each one you choose, DESCRIBE how bacteria carry out the role and DISCUSS its ecological importance.
   b) EXPLAIN how bacteria can be altered to make genetically engineered products.

2010 B All Questions          Scoring Guidelines             Sample Responses Q4 

2010B#4
On a trip to a dense forest, a biologist noticed that millipedes (small invertebrates) were plentiful under logs but were rarely seen in any other location.

a) PROPOSE THREE environmental variables (two abiotic and one biotic) that could explain why millipedes are found more frequently under logs.
b) For ONE of the abiotic environmental variables you chose above, DESIGN a controlled experiment  to test a hypothesis tha tthis factor affects the distribution of millipedes on the forest floor.  DESCRIBE data that would support your hypothesis.
c) Suppose that you were examining the distribution of a plant, instead of the millipede.  DESCRIBE modifications in the experiment that you designed in (b) that would be required to determine whether the abiotic factor you chose affects the distribution of the plant

 

2009

2009 All Questions              Scoring Guidelines        Sample Responses Q1

2009 #1

An experiment on a species of small freshwater fish recorded their behavioral responses to different temperatures.  Ten fish were each tested once, one at a time.

To begin the experiment, a fish was removed from a stock tank (maintained at 22 °C ) and placed in the temperature-gradient tank drawn below.  After the fish had spent 30 minutes in the temperature-gradient tank, the section where the fish was located was recorded.  Additional observations were recorded every 5 minutes, for a  total of 7 observations per fish.  A summary of the combined data for all 10 fish appears below.
a) On the axes provided, CONSTRUCT the appropriate type of labeled graph showing the relationship between water temperature and fish distribution.  SUMMARIZE the outcome of the experiment.
b) IDENTIFY TWO variables that were not specifically controlled in the experimental design, and DESCRIBE how these variables might have affected the outcome of the experiment
c) DISCUSS TWO ways that water temperature could affect the physiology of the fish in this experiment.



2009 All Questions              Scoring Guidelines        Sample Responses Q2


2009 #2
ATP and GTP are primary sources of energy for biochemical reactions.
a) DESCRIBE the structure of the ATP or the GTP molecule
b) EXPLAIN how chemiosmosis produces ATP
c) DESCRIBE TWO specific cell processes that require ATP and explain how ATP is used in each process.
d) An energy pyramid for a marine ecosystem is shown below.  LABEL each trophic level.of the pyramid  and provide an example of a marine organism found in each level. EXPLAIN why the energy available at the top layer of the pyramid is a small percentage of the energy present at the bottom of the pyramid.


2009 All Questions              Scoring Guidelines        Sample Responses Q3

2009 #3
Phylogeny is the evolutionary history of a species.
   a) The evolution of a species is dependent on changes in the genome of the species.  IDENTIFY TWO mechanisms of genetic change, and EXPLAIN how each
          affects genetic variation.
   b) Based on the data in the table below, DRAW a phylogenetic tree that reflects the  evolutionary relationships of the organisms based on the differences in
        their cytochrome c amino-acid sequences and EXPLAIN the relationships of the organisms.  Based on the date, IDENTIFY which organism is the most
        closely related to the chicken and EXPLAIN your choice.
   c) DESCRIBE TWO types of evidence-other than the comparison of proteins- that can be used to determine they phylogeny of organisms.
       DISCUSS one strength of each type of evidence you described.

2009 All Questions              Scoring Guidelines        Sample Responses Q4

2009#4
The flow of genetic information from DNA to protein in eukaryotic cells is called the central dogma of biology.

a) EXPLAIN   the role of each of the following in protein synthesis in eukaryotic cells.
     - RNA polymerase
     - Spliceosomes (snRNPs)
     - Codons
    - Ribosomes
    - tRNA
b) Cells regulate both protein synthesis and proteins activity.  DISCUSS TWO specific mechanisms of protein regulation in eukaryotic cells.
c) The central dogma does not apply to some viruses.  Select a specific virus or type of virus and EXPLAIN how it deviates from the central dogma.


2009 B All Questions          Scoring Guidelines          Sample Responses Q1

2009B #1
 DESCRIBE how a plasmid can be genetically modified to include a piece of foreign DNA that alters the phenotype of bacterial cells transformed with the modified plasmid.  DESCRIBE a procedure to determine which bacterial cells have been successfully transformed.

2009 B All Questions          Scoring Guidelines         Sample Responses Q2

2009B #2
DISCUSS the patterns of sexual reproduction in plants.  COMPARE and CONTRAST reproduction in nonvascular plants  with that in flowering plants.  INCLUDE the following topics in your discussion.
    a) alternation of generations
    b) mechanisms that bring female and male gametes together
    c) mechanisms that disperse offspring to new locations

2009B All Questions         Scoring Guidelines           Sample Responses Q3
2009B #3.
Water is essential to all living things.
     (a)
Discuss THREE properties of water
   
 (b)
Explain each of the following in terms of the properties of water. You are not limited to the three               
         properties discussed in part (a):
           
 • the role of water as a medium for the metabolic processes of cells
             
• the ability of water to moderate temperature within living organisms and in organisms’ environments
            
• the movement of water from the roots to the leaves of plants

2009 B All Questions          Scoring Guidelines        Sample Responses Q4

2009B #4
Many organisms require a continuing source of oxygen for respiration.  DISCUSS important structural and physiological adaptations for oxygen uptake in THREE of the following:
    - a paramecium
    - a tree
    - a fish
    - a mammal


2008

2008 All Questions      Scoring Guidelines       Sample Responses Q1
2008 #1.
The physical structure of a protein often reflects and affects its function.
    
 (a)
Describe THREE types of chemical bonds/interactions found in proteins.
            For each type,
describe its role in determining protein structure.
     
(b) Discuss how the structure of a protein affects the function of TWO of the following.
           
• Muscle contraction
           
• Regulation of enzyme activity
           
• Cell signaling

2008 All Questions      Scoring Guidelines     Sample Responses Q2

2008 #2.
Consumers in aquatic ecosystems depend on producers for nutrition.
(a)
Explain the difference between gross and net primary productivity.
(b)
Describe a method to determine net and gross primary productivity in a freshwater pond overa 24-hour period.

In an experiment, net primary productivity was measured, in the early spring, for water samples taken from different depths of a freshwater pond in a temperate deciduous forest.

(c) Explain the data presented by the graph, including a description of the relative rates of metabolic processes occurring at different depths of the pond.

(d) Describe how the relationship between net primary productivity and depth would be expected to differ if new data were collected in mid-summer from the same pond. Explain your prediction. 

2008 All Questions              Scoring Guidelines           Sample Responses Q3
 
2008 #3
Regulation is an important aspect of biological processes.
For FOUR of the following processes DESCRIBE the specific role of the regulator and DISCUSS how the process will be altered if the regulation is disrupted.


2008 All Questions              Scoring Guidelines       Sample Responses Q4 
2008 #4
Flowering plants have evolved various strategies for fertilization.
(a) DESCRIBE the process of fertilization in flowering plants.
(b) DISCUSS TWO mechanisms of pollen transfer and the adaptations that facilitate each mechanism.

Some species of flowering plants have evolved mechanisms to prevent self-fertilization.
(c) DISCUSS an evolutionary advantage of preventing self-fertilization.
(d) DESCRIBE TWO mechanisms that prevent self-fertilization.




2008: Form B

2008B ALL Questions          Scoring Guidelines        Sample Responses Q1
2008B #1
Measurements of dissolved oxygen (DO) are used to determine primary productivity in bodies of water.
~ EXPLAIN the relationship of dissolved oxygen to primary productivity
~How would the predicted levels of DO differ in each of the following pairs of water samples? Provide support for your prediction.  Be sure to include a   
    discussion of net productivity and gross productivity in your answer.
I. Pond water at 25° C vs. pond water at 15 °C
II. Pond water placed in the dark for 24 hours vs. and water placed in light for 24 hours.

2008B ALL Questions          Scoring Guidelines        Sample Responses Q2
2008B #2
Many biological structures are composed of smaller units assembled into more complex structures having functions based on their structural organization.

For THREE of the following complex structures, DESCRIBE the smaller units, their assembly into the larger structures, and one major function of these larger, organized structures.
(a) A eukaryotic chromosome
(b) A mature angiosperm root
(c) A colony of bees
(d) An inner membrane of a mitochondrion
(e) An enzyme

2008B ALL Questions          Scoring Guidelines        Sample Responses Q3
2008B #3
Evolution is one of the unifying themes of biology. Evolution involves changes in the frequencies of alleles in a population.  For a particular genetic locus in a population, the frequency of the recessive allele (a) is 0.4 and the frequency of the dominant allele (A) is 0.6.
(a) What is the frequency of each genotype (AA, Aa, aa) in this population? What is the frequency of the dominant phenotype?
(b) How can the Hardy-Weinberg principle of genetic equilibrium be used to determine whether this population is evolving?
(c) Identify a particular environmental change and describe how it might alter allelic frequencies in this population.  Explain which condition of the Hardy-Weinberg principle would not be met?



2008B ALL Questions          Scoring Guidelines            Sample Responses Q4
2008B #4
Scientists use the concept of homology in identifying evolutionary relationships among organisms.  Features shared by two groups of of organisms are said to be homologous if the similarities reflect shared ancestry. Homology is found in comparisons of structural, molecular, biochemical, developmental, physiological, and behavioral characteristics of organisms.  Select THREE of the following hypotheses and EXPLAIN TWO examples of homology that support each hypothesis.
(a) Chloroplasts are related to photosynthetic prokaryotes
(b) Spiders and insects are closely related.
(c) Echinoderms (sea stars and their relatives) are closely related to the chordates (the phylum that includes the vertebrates).
(d) Reptiles and  birds are closely related.
(e) Humans and chimpanzees are closely related primates.

 

2007


2007 All Questions          Scoring Guidelines         Student Performance Q&A            Sample Responses Q1

2007 #1
Membranes are essential components.
(a) IDENTIFY THREE macromolecules that are components of the plasma membrane in a eukaryotic cell and discuss the structure and function of each.
(b) EXPLAIN how membranes participate in THREE of the following biological processes.
~ Muscle contraction
~ Fertilzation of an egg
~ Chemiosmotic production of ATP
~ Intercellular signaling

2007 All Questions        Scoring Guidelines         Student Performance Q&A            Sample Responses Q2

2007 #2.
Cephalization and the development of a brain were important steps in animal evolution.
(a) DISCUSS the evolutionary origin and adaptive significance of cephalization in animal phyla.
(b) DESCRIBE the development of the nervous system in the vertebrate embryo.
(c) At the sound of shattering glass, people quickly turn their heads.  DISCUSS how the human nervous system. functions to produce this type of response to an external stimulus.


2007 All Questions        Scoring Guidelines         Student Performance Q&A            Sample Responses Q3
2007#3.
Compared with other terrestrial biomes, deserts have extremely low productivity.
(a) DISCUSS how temperature, soil compostition, and annual precipitation limit productivity in deserts.
(b) DESCRIBE a four-organism food chain that might characterize a desert community, and IDENTIFY the trophic level of each organism.
(c) DESCRIBE the results depicted in the graph.  EXPLAIN one anatomical difference and one physiological difference between species A and B that account for the CO2 uptake patterns shown.  DISCUSS the evolutionary significance of each difference.



2007 All Questions    Scoring Guidelines         Student Performance Q&A    Sample Responses Q4

2007 #4.
A bacterial plasmid is 100 kb in length. The plasmid DNA was digested to completion with two restriction enzymes in three separate treatments: EcoRI, HaeIII, and EcoRI + HaeIII (double digest). The fragments were then separated with electrophoresis, as shown.
   

a) Using the circle provided, CONSTRUCT a labeled diagram of the restriction map of the plasmid. EXPLAIN how you developed your map.
b) DESCRIBE how:recombinant DNA technology could be used to insert a gene of interest into a bacterium
recombinant bacteria could be identified
expression of the gene of interest could be ensured
c) DISCUSS how a specific genetically modified organism might provide a benefit for humans and at the same time pose a threat to a population or ecosystem.





2007: Form B

2007B All  Questions            Scoring Guidelines         Sample Responses Q1
2007B#1
Without adaptive behaviors, animals would not survive.
(a) DESCRIBE what innate and learned behaviors are.  EXPLAIN the adaptive value of each of these two categories of behavior are to an individual animal.
(b) During mating season, male snakes exhibit tracking behavior when they follow chemical pheromones deposited on the ground by females. DESIGN a controlled experiment to determine whether a male snake will track only a female of his species or will also follow the female  of a related species.
(c) Interactions among populations may have an effect on densities of the species that interact. 


2007B All  Questions            Scoring Guidelines         Sample Responses Q2

2007B#2
The defenses of the human body to the entry and establishment of a pathogen (disease-causing organism) can be divided into nonspecific and specific responses.
(a) EXPLAIN how THREE types of nonspecific defenses can prevent the entry and/or establishment of a pathogen in a person's body.
(b) DISCUSS how the immune system responds to an initial pathogenic exposure, and how this initial exposure can lead to a quicker response following a second exposure to the same pathogen.
(c) EXPLAIN the biological mechanisms that lead to the rejection of transplanted organs.

2007B All  Questions            Scoring Guidelines                 Sample Responses Q3

2007 B
3. A molecule of messenger RNA (mRNA) has just been synthesized in the nucleus of a human cell.

            a) What types of modifications may occur to this RNA before it leaves the nucleus?
            b) Once in the cytoplasm, how is the mRNA translated to a protein?
            c) If the cell is a secretory cell, how is the protein from part (b) eventually targeted, packaged, and secreted to the exterior of the cell?

2007B All  Questions            Scoring Guidelines             Sample Responses Q4


2007B #4
The energy flow in ecosystems is based on the primary productivity of autotrophs.
(a) DISCUSS the energy flow through an ecosystem and the relative efficiency with which it occurs.
(b) DISCUSS the impact of the following on energy flow on a global scale.
~ Deforeestation
~ Global climate change


2006

2006 All Questions            Scoring Guidelines      Student Performance Q&A                 Sample Responses Q1

2006
1. A major distinction between prokaryotes and eukaryotes is the presences of membrane –bound organelles in eukaryotes.
   a) DESCRIBE the structure and function of TWO eukaryotic membrane-bound organelles other than the nucleus.
   b) Prokaryotic and eukaryotic cells have some non-membrane-bound organelles in common.
        DESCRIBE the function of TWO of the following and DISCUSS how each differs in prokaryotes and eukaryotes.
         -DNA
         -Cell wall
         - Ribosomes
    c) EXPLAIN the endosymbiotic theory of the origin of eukaryotic cells and DISCUSS an example of evidence supporting this theory.

2006 All Questions            Scoring Guidelines     Student Performance Q&A            Sample Responses Q2
2006#2



According to fossil and recent published observations, two species of leaf-eating beetles (species A and species B) have existed on an island in the Pacific Ocean for over 100,000 years. In 1964 a third species of leaf-eating beetle (species C) was accidentally introduced on the island.  The populations size of each species has been regularly monitored as shown in the graph above.
(a) PROPOSE an explanation for the pattern of population density observed in species C.
(b) DESCRIBE the effect that the introduction of the beetle species C has had on the population density of species A and species B.  PROPOSE an explanation for the patterns of populations density observed in species A and in species B.
(c) PREDICT the populations density of species C in 2014.  Provide a biological explanation for your prediction.
(d) EXPLAIN why invasive species are often successful in colonizing new habitats.




2006 All Questions            Scoring Guidelines     Student Performance Q&A            Sample Responses Q3
2006#3
The movement of water through vascular plants is important to their survival.
(a) EXPLAIN the mechanism of water movement through vascular plants during transpiration.  Include a discussion of how the anatomy of vascular plants and properties of water contribute to this process.
(b) EXPLAIN how gas exchange affects transpiration.
(c) DESCRIBE TWO adaptations that affect the rate of transpiration in desert plants.



2006 All Questions            Scoring Guidelines     Student Performance Q&A            Sample Responses Q4
2006#4
The evolution of circulatory systems allowed larger and more complex animals to arise.
(a) DESCRIBE the respiratory and digestive systems' specialized structures that facilitate the movement of oxygen and glucose into the circulatory system of mammals.
(b) EXPLAIN how oxygen and glucose are transported within the circulatory system of mammals.
(c) EXPLAIN the transfer of oxygen and glucose from the blood and into the active cells of mammals.



2006: Form B

2006B All Questions             Scoring Guidelines            Sample Responses Q1
2006B #1
Sexual reproduction requires that half of the chromosomes in a zygote come from one parent and the other half from the second parent.
(a) DESCRIBE the process by which a germ cell's complement of chromosomes is halved in the formation of gametes.
(b) Choose ONE organism or group of organisms that reproduce ASEXUALLY. DESCRIBE the mode of reproduction in that organism and EXPLAIN the advantages to the organism of asexual reproduction.
(c)Choose ONE organism or group of organisms that reproduce SEXUALLY. DESCRIBE the mode of reproduction in that organism and EXPLAIN the advantages to the organism of sexual reproduction.

2006B All Questions             Scoring Guidelines            Sample Responses Q2
2006B #2
The relationship of structure and function is one of the major themes in biology.  For THREE of the following structure/function pairs, DESCRIBE the structure and then EXPLAIN how the function is related to the  structure.
(a) Enzyme structure/catalysis
(b) mRNA structure/protein synthesis
(c) Cell membrane/signal transduction
(d) Membrane protein structure/active transport or facilitate diffusion

2006B All Questions             Scoring Guidelines            Sample Responses Q3

2006B #3

While studying transpiration, a scientist used a dendrometer to record the small daily changes in the diameter of a tree trunk at two different heights (2 meters and 3 meters) above the ground at the same time. The diameter decreased in the daytime.  This decrease happened first at the higher location. DISCUSS the following  in relation to water movement in plants.
(a) INDENTIFY how TWO different environmental factors could be involved in the daily fluctuations shown above.
(b) DISCUSS the mechanisms involved in the uptake and transport of water by vascular plants.
(c) DISCUSS the role of water in the normal functioning of plants.

 

2006B All Questions             Scoring Guidelines            Sample Responses Q4
2006B #4
In many ways, all organisms in a food web can be said to be solar-powered.  The producer level of the food web is responsible for the transformation of the solar energy into a form that can be used by other living organisms.
(a) DISCUSS the role of green plants in transforming the Sun's energy into a form that can ultimately be used by heterotrophs.
(b) DISCUSS the flow of energy from producers through top carnivores in a food web in terms of the laws of thermodynamics.



2005

2005 All Questions         Scoring Guidelines                  Scoring Commentary             Sample Responses Q1

2005 #1. Yeast cells are placed in an apparatus with a solution of sugar (a major nutrient for yeast metabolism). The apparatus detects bubbles of gas released by the yeast cells. The rate of respiration varies with the surrounding temperatures as indicated by the data below.

 Temperature (°C) 0 10  20  30  40  50  60  70 
 Number of bubbles of gas produced/min 12 

(a) Graph the results on the axes provided. Determine the optimum temperature for respiration in the yeast.

(b) Respiration is a series of enzyme-catalyzed reactions. Using your knowledge of enzymes and the data above, analyze and explain the results of this experiment.

(c) Design an experiment to test the effect of varying the pH of the sugar solution on the rate of respiration. Include a prediction of the expected results.

2005 All Questions         Scoring Guidelines                  Scoring Commentary             Sample Responses Q2

2005 #2. The unit of genetic organization in all living organisms is the chromosome.
(a) Describe the structure and function of the parts of a eukaryotic chromosome. You may wish to include a diagram
      as part of your description.

(b) Describe the adaptive (evolutionary) significance of organizing genes into chromosomes.
(c) How does the function and structure of the chromosome differ in prokaryotes?

2005 All Questions         Scoring Guidelines                  Scoring Commentary            

2005 #3
Angiosperms (flowering plants) have wide distribution in the biosphere and the largest number of species in the plant kingdom.
(a) DISCUSS the function of FOUR structures for reproduction found in angiosperms and the adaptive (evolutionary) significance of each.
(b) Mosses (bryophytes) have not achieved the widespread terrestrial success of angiosperms. DISCUSS how the anatomy and reproductive strategies of mosses limit their distribution.
(c) EXPLAIN alternation of generations in either angiosperms or mosses.

2005 All Questions         Scoring Guidelines                  Scoring Commentary            Sample Responses Q4

2005 #4.
An important defense against diseases in vertebrate animals is the ability to eliminate, inactivate, or destroy
foreign substances and organisms. Explain how the immune system achieves THREE of the following:

• Provides an immediate nonspecific immune response
• Activates T and B cells in response to an infection
• Responds to a later exposure to the same infectious agent
•
Distinguishes self from non-self  


2005: Form B

2005B All Questions         Scoring Guidelines            Scoring Commentary         Sample Responses

2005B #1
Survival of organisms depends on adaptive behavior and species interactions.
(a) Behaviors of organisms may be influenced by environmental factors. Select two of the following types of behavior. For each type, EXPLAIN
(i) how the environment affects the behavior, and
(ii) why this behavior increases the survivorship of individuals of a species.
~ Taxis/Kinesis
~Migration
~ Courtship

Interactions among populations may have an effect on densities of the species that interact. Predation represents an important interaction among populations.  The curves below depict the population densities of three species: a small herbivore, a larger herbivore, and a carnivore.
IDENTIFY which curve represents which of the species listed, and JUSTIFY your answer by DESCRIBING the changes in the population densities of these three species over time.

 

2005B All Questions         Scoring Guidelines            Scoring Commentary         Sample Responses

2005B #2
In the evolution of organisms, major adaptations arose in certain groups, opening new evolutionary possibilities.  For TWO of the following types of organisms, DISCUSS evolutionary significance of the features listed.
(a) Flowering plants: flowers, fruits and seeds, and broad leaves
(b) Flatworms: three germ layers, bilateral symmetry, and cephalization
(c) Segmented worms: segmentation, coelom, and digestive system
(d) Reptiles: amniotic eggs, waterproof skin, and well-developed lungs

2005B All Questions         Scoring Guidelines            Scoring Commentary         Sample Responses
2005B #3
Protein synthesis is vital for cell growth and metabolism.
(a) DESCRIBE transcription and translation
(b) IDENTIFY similarities between transcription and translation
(c) IDENTIFY differences between transcription and translation
(d) DESCRIBE structural changes that can occur to a protein after translation to make it function properly.

 

2005B All Questions         Scoring Guidelines            Scoring Commentary         Sample Responses

2005B #4
Water potential in potato cells was determined in the following manner.  The initial masses of six groups of potato cores were measured.  The potato cores were placed in sucrose solutions of various molarities. The masses of the cores were measured again after 24 hours.  Percent changes in mass were calculated. The results are shown below.


(a) GRAPH these data on the axes provided.  From you graph, find the apparent molar concentration of the potato core cells
(b) What are the components of water potential , and why is water potential important for movement of water in plants?
(c) PREDICT what would happen to typical animal cells placed in 0.0 M and 1.0 M sucrose solutions, and EXPLAIN your prediction

 

2004

2004 All Questions        Scoring Guidelines        Scoring Commentary         Sample Responses Q1

2004#1
Meiosis reduces chromosome number and rearranges genetic information.
   (a)
EXPLAIN how the reduction and rearrangement are accomplished in meiosis
   (b) Several human disorders occur as a result of defects in the meiotic process.
       
 IDENTIFY ONE such chromosomal abnormality; what effects does it have on the phenotype of people with the disorder?
         DESCRIBE how this abnormality could result from a defect in meiosis.
   (c) Production of offspring by parthenogenesis or cloning bypasses the typical meiotic process.
        
DESCRIBE either parthenogenesis or cloning and COMPARE the genomes of the offspring with those of the parents.

2004 All Questions        Scoring Guidelines        Scoring Commentary         Sample Responses Q2

2004#2
2.  Darwin is considered the "father of evolutionary biology." Four of his contributions to the field of evolutionary biology are listed below:
         -The nonconstancy of species
         -Branching evolution, which implies the common descent of all species
         -Occurrence of gradual changes in species
         -Natural selection as the mechanism for evolution
(a) For EACH of the four contributions listed above, DISCUSS one example of supporting evidence.
(b) Darwin's ideas have been enhanced and modified as new knowledge and technologies have become available.
        DISCUSS how TWO of the following have modified biologist's interpretation of Darwin's original contributions.
        - Hardy-Weinberg equilibrium
        - Punctuated equilibrium
        - Genetic engineering

        

2004 All Questions        Scoring Guidelines        Scoring Commentary          Sample Responses Q3

2004 #3.
 A controlled experiment was conducted to analyze the effects of darkness and boiling on the photosynthetic rate of incubated chloroplast suspensions. The dye reduction technique was used. Each chloroplast suspension was mixed with DPIP, an electron acceptor that changes from blue to clear when it is reduced. Each sample was placed individually in a spectrophotometer and the percent transmittance was recorded. The three samples used
were prepared as follows.
   • Sample 1 - chloroplast suspension + DPIP
   • Sample 2 - chloroplast suspension surrounded by foil wrap to provide a dark environment + DPIP
   • Sample 3 - chloroplast suspension that has been boiled + DPIP

TIME
(MIN)
Light, Unboiled
% Transmittance
SAMPLE 1
Dark, Unboiled
% Transmittance
SAMPLE 2
Light, Boiled
% Transmittance
SAMPLE 3
0 28.8 29.2 28.8
5 48.7 30.1 29.2
10 57.8 31.2 29.4
15 62.5 32.4 28.7
20 66.7 31.8 28.5

(a) On the axes provided, construct and label a graph showing the results for the three samples.
(b) Identify and explain the control or controls for this experiment.
(c) The differences in the curves of the graphed data indicate that there were differences in the number of electrons produced in the three samples during the experiment. Discuss how electrons are generated in photosynthesis and why the three samples gave different transmittance results.

2004 All Questions        Scoring Guidelines        Scoring Commentary      Sample Responses Q4
 
2004 #4.
Organisms rarely exist alone in the natural environment. The following are five examples of symbiotic
relationships.
   
•  Plant root nodules
   •  Digestion of cellulose
   •  Epiphytic plants
   •  AIDS (acquired immune deficiency syndrome)
   
•  Anthrax

Choose FOUR of the above and for each example chosen,
(a) identify the participants involved in the symbiosis and describe the symbiotic relationship, and
(b) discuss the specific benefit or detriment, if any, that each participant receives from the relationship.

2004B All Questions            Scoring Guidelines         Scoring Commentary         Sample Responses Q1

2004B #1
Prokaryotes are found throughout the biosphere.  Answer TWO of the following.
(a) Provide THREE examples of adaptations found in various prokaryotes.  EXPLAIN how these three adaptations have ensured the success of prokaryotes.
(b) DISCUSS how prokaryotes early in Earth's history altered environments on Earth
(c) DISCUSS THREE ways in which prokaryotes continue to have ecological impact today.


2004B All Questions            Scoring Guidelines         Scoring Commentary         Sample Responses Q2

2004B #2
In most aquatic environments, primary production is affected by  the light available to the community of organisms.
Using measurements of dissolved oxygen concentration to determine primary productivity, DESIGN a controlled experiment to test the hypothesis that primary productivity is affected by either the intensity or wavelength of light. In your answer, be sure to include the following:
~ A statement of the specific hypothesis that you are testing.
~ A description of your experimental design (Be sure to include a description of what data you would collect and how you would present and analyze the date using a graph)
~ A description of results that would support your hypothesis

2004B All Questions            Scoring Guidelines         Scoring Commentary         Sample Responses Q3

2004B #3
Homeostasis, maintaining a steady-internal environment, is a characteristic of all living organisms.  Choose THREE of the following physiological parameters and for each, DESCRIBE how homeostasis is maintained in an organism of your choice. Be sure to indicate what animal you have chosen for each parameter.  You ay use the same animal or different animals for your three descriptions.
~ Blood-glucose levels
~ Body temperature
~ pH of the blood
~ Osmotic concentration of the blood
~ Neuron resting-membrane potential

2004B All Questions            Scoring Guidelines         Scoring Commentary         Sample Responses Q4

2004B #4
Organisms differ from one another and yet share common characteristics.
(a) Select TWO kingdoms and briefly DESCRIBE THREE characteristics used to distinguish between members of one kingdom and members of the other
(b) DESCRIE THREE characteristics (at least one molecular and one cellular) that members of these two kingdoms share.
(c) PROPOSE an explanation for the existance of similarities and differences between the two kingdoms.


2003

2003 All Questions     Scoring Guidelines      Scoring Commentary  Student Performance Q&A    Sample Responses Q1

1. In fruit flies, the phenotype for eye color is determined by a certain locus. E indicates the dominant allele and e ndicates the recessive allele. The cross between a male wild-type fruit fly and a female white-eyed fruit fly produced the following offspring.

(a) Determine the genotypes of the original parents (P generation) and explain your reasoning. You may use Punnett squares to enhance your description, but the results from the Punnett squares must be discussed in your answer.

(b) Use a Chi-squared test on the F2 generation data to analyze your prediction of the parental genotypes. Show all your work and explain the importance of your final answer.

(c) The brown-eyed female in the F1 generation resulted from a mutational change. Explain what a mutation is, and discuss two types of mutations that might have produced the brown-eyed female in the F1 generation.

2003 All Questions     Scoring Guidelines      Scoring Commentary   Student Performance Q&A   Sample Responses Q2
2003 #2
Regulatory (control) mechanisms in organisms are necessary for survival.  Choose THREE of the following examples and EXPLAIN how each is regulated.
(i) Flowering in plants
(ii) Water balance in plants
(iii) Water balance in terrestrial vertebrates
(iv) Body temperature in terrestrial vertebrates

 

2003 All Questions     Scoring Guidelines      Scoring Commentary    Student Performance Q&A   Sample Responses Q3

3. Many populations exhibit the following growth curve:

(a) Describe what is occurring in the population during phase A.
(b) Discuss THREE factors that might cause the fluctuations shown in phase B.

(c) Organisms demonstrate exponential (r) or logistic (K) reproductive strategies. Explain these two strategies and discuss how they affect population size over time.

2003 All Questions     Scoring Guidelines      Scoring Commentary   Student Performance Q&A   Sample Responses Q4

 4. Death is a natural and necessary part of life cycles at all levels of organization.
    (a) Discuss TWO examples of how cell death affects the development and functioning of a multicellular organism.
    (b) Discuss ONE example of how substances are degraded and reused in cells.
    (c) Discuss the evolutionary significance of death.

2003B  Questions             Scoring Guidelines        Scoring Commentary   Sample Responses Q1

2003B #1.
A difference between prokaryotes and eukaryotes is seen in the organization of their genetic material.
        a) DISCUSS the organization of the genetic material in prokaryotes and eukaryotes.
        b) CONTRAST the following activities in prokaryotes and eukaryotes.
                - Replicaton of DNA
                - Transcription or translation
                - Gene regulation
                - Cell division
 

2003B  Questions             Scoring Guidelines        Scoring Commentary   Sample Responses Q2
2003B #2.
Hormones play important roles in regulating the lives of many living organisms.

(a) For TWO of the following physiological responses, explain how hormones cause the response in plants.
     • increase in height
     • adjustment to change in light
     • adjustment to lack of water

 (b) For TWO of the following physiological responses, explain how hormones cause the response in animals.
     • increase in height
     • adjustment to change in light
     • adjustment to lack of water

 (c) Describe TWO different mechanisms by which hormones cause their effects at the cellular level.

2003B  Questions             Scoring Guidelines        Scoring Commentary   Sample Responses Q3

2003B #3.
Water is important for all living organisms. The functions of water are directly related to its physical properties.

(a) Describe how the properties of water contribute to TWO of the following.
     • transpiration

     • thermoregulation in endotherms
     • plasma membrane structure

(b) Water serves as a reactant and a product in the carbon cycle. Discuss the role of water in the carbon cycle.

(c) Discuss the impact of one human activity on the water cycle.

2003B  Questions             Scoring Guidelines            Scoring Commentary         Sample Responses Q4

2003 B #4.
Biologists are interested in preserving the diversity of living organisms on the planet.

(a) Explain THREE of the following processes or phenomena, using an appropriate example for each.
     • mutation
     • adaptive radiation
     • polyploidy
     
• population bottlenecks
     • growth of the human population

b) For each process or phenomenon you selected in (a), discuss its impact on the diversity of life on Earth.

2002

UNKNOWN YEAR? (had this in my stuff as 2002)       Rubric
Structure related to function is one of the unifying themes in biology.
  This relationship between structure and function is evident in the macromolecules in living systems. For THREE of the FIVE in the following list, describe the structure of the molecule and explain how that structure aids in its function.
        
a. Starch and glycogen as energy storage molecules
         b. Cellulose and chitin as structural molecules
         c. enzymes
         d. phospholipids and their role in cell membranes
         e. DNA and its role in determining characteristics in organisms

2002 All questions    Scoring Guidelines     Scoring Commentary      Sample Responses Q1

2002 #
1. The human genome illustrates both continuity and change.
(a) Describe the essential features of two of the procedures/techniques below. For each of the procedures/ techniques you describe, explain how its
       application contributes to understanding genetics.

        
~ The use of a bacterial plasmid to clone and sequence a human gene
         ~ Polymerase chain reaction (PCR)
         ~ Restriction fragment length polymorphism (RFLP) analysis

(b) All humans are nearly identical genetically in coding sequences and have many proteins that are identical in structure and function. Nevertheless, each human has a unique DNA fingerprint. Explain this apparent contradiction.

2002 All questions    Scoring Guidelines     Scoring Commentary         Sample Responses Q2 

2002 #2
 The activities of organisms change at regular time intervals. These changes are called biological rhythms. The graph depicts the activity cycle over a 48-hour period for a fictional group of mammals called pointy-eared
bombats, found on an isolated island in the temperate zone.

 

(a) Describe the cycle of activity for the bombats.
Discuss how three of the following factors might affect the physiology and/or behavior of the bombats to result in this pattern of activity.

~ temperature
~
food availability
~
presence of predators
~
social behavior

(b) Propose a hypothesis regarding the effect of light on the cycle of activity in bombats.
Describe
a controlled
experiment that could be performed to test this hypothesis, and the results you would expect.

2002 All questions    Scoring Guidelines     Scoring Commentary        Sample Responses Q3 

2002 #3
The complexity of structure and function varies widely across the animal kingdom. Despite this variation,
animals exhibit common processes. These include the following.

~ transport of materials
~response to stimuli

~gas exchange
~locomotion

(a) Choose two of the processes above and for each, describe the relevant structures and how they function to accomplish the process in the following phyla.
      Cnidaria (e.g., hydra, jellyfish)

      Annelida (e.g., earthworm)
      Chordata (e.g., mouse)

(b) Explain the adaptive (evolutionary) value(s) of the structural examples you described in part a.

2002 All questions    Scoring Guidelines     Scoring Commentary          Sample Responses Q4

2002 #4.
The following experiment was designed to test whether different concentration gradients affect the rate of
diffusion. In this experiment, four solutions (0% NaCl, 1% NaCl, 5% NaCl , and 10% NaCl) were tested under identical conditions. Fifteen milliliters (mL) of 0% NaCl were put into a bag formed of dialysis tubing that is permeable to Na+, Cl-, and water. The same was done for each NaCl solution. Each bag was submerged in a separate beaker containing 300 mL of distilled water. The concentration of NaCl in mg/L in the water outside each bag was measured at 40-second intervals. The results from the 5% bag are shown in the table below.

CONCENTRATION IN mg/L OF NaCl OUTSIDE THE 5% NaCl BAG

Time (seconds)  NaCl (mg/L) 
40  130 
80  220 
120  320 
160  400 

(a) On the axes provided, graph the data for the 5% NaCl solution.

(b) Using the same set of axes, draw and label three additional lines representing the results that you would predict for the 0% NaCl, 1% NaCl, and 10% NaCl solutions. Explain your predictions.

(c) Farmlands located near coastal regions are being threatened by encroaching seawater seeping into the soil. In terms of water movement into or out of plant cells, explain why seawater could decrease crop production. Include a discussion of water potential in your answer.

2002B All Questions            Scoring Guidelines        Scoring Commentary             Sample Responses Q1

2002B #1.
 Bacteria were cultured in a system that allowed for the continual addition of fresh nutrients and the removal of waste products. Bacteriophage (virus) were added at the time shown and the following population changes
were observed.

(a) Describe and explain the observed results.
(b) Discuss the infection cycle of a DNA virus from attachment to lysis.
(c) Describe how the genome of a retrovirus like HIV (Human Immunodeficiency Virus) becomes
incorporated into the genome of the host cell.

2002B All Questions            Scoring Guidelines        Scoring Commentary       Sample Responses Q2

2002B #2.
In mammals, heart rate during periods of exercise is linked to the intensity of exercise.

(a) Discuss the interactions of the respiratory, circulatory, and nervous systems during exercise.
(b) Design a controlled experiment to determine the relationship between intensity of exercise and
heart rate.
(c) On the axes provided below, indicate results you expect for both the control and the experimental groups for the controlled experiment you described in part B. Remember to label the axes.

2002B All Questions            Scoring Guidelines        Scoring Commentary      Sample Responses Q3

2002B #3.
The physical form of cells and organisms is often influenced by special structural polymers. Choose one
polymer from each of the following three pairs of polymers:
     Pair 1: tubulin . . myosin
     Pair 2: cellulose . . chitin
     Pair 3: messenger RNA . . transfer RNA

For each of the three polymers you have chosen, describe its
(a) structure, and
(b) role in a cell or organism.

2002B All Questions            Scoring Guidelines        Scoring Commentary         Sample Responses Q4

2002B #4.
A triploblastic animal is one in which three germ layers form during embryonic development. Triploblastic animals include acoelomate, pseudocoelomate, and coelomate (eucoelomate) organisms.

(a) Identify the three germ layers of a triploblastic embryo and discuss the fates of these germ layers in embryonic development.
(b) Describe acoelomate, pseudocoelomate, and coelomate body plans. Identify an animal that is representative of each of these types of body plan.
(c) Compare and contrast the digestive systems of an acoelomate and a coelomate organism.

 

2001 

2001 All Questions     Scoring Guidelines     Scoring Commentary      Sample Responses Q1
2001 #1
 In biological systems, structure and function are related. Choose three of the following components of organ systems.
      
alveolus             villus
      sarcomere          capillary
        nephron           
neuron

(a) For each component, describe the structure of the component and explain how that structure is responsible for the function of that component.

(b) For the three components that you chose in part a, explain how the structure of the component contributes  to the functioning of the organ system to which it belongs. 

2001 All Questions     Scoring Guidelines     Scoring Commentary    Sample Responses Q2

2001 #2
Charles Darwin proposed that evolution by natural selection was the basis for the differences that he saw in similar organisms as he traveled and collected specimens in South America and on the Galapagos Islands.
(a) Explain the theory of evolution by natural selection as presented by Darwin.
(b) Each of the following relates to an aspect of evolution by natural selection. Explain three of the following.

(i) Convergent evolution and the similarities among species (ecological equivalents) in a particular biome (e.g., tundra, taiga, etc.)
(ii) Natural selection and the formation of insecticide-resistant insects or antibiotic-resistant bacteria
(iii) Speciation and isolation
(iv) Natural selection and behavior such as kinesis, fixed-action-pattern, dominance hierarchy, etc.

(v) Natural selection and heterozygote advantage

2001 All Questions     Scoring Guidelines     Scoring Commentary     Sample Responses Q3

2001 #3
A biologist measured dissolved oxygen in the top 30 centimeters of a moderately eutrophic (mesotrophic) lake in the temperate zone. The day was bright and sunny, and the wind was calm. The results of the observations are presented below.

(a) Using the graph paper provided, plot the results that were obtained. Then, using the same set of axes, draw and label an additional line/curve representing the results that you would predict had the day been heavily overcast.

(b) Explain the biological processes that are operating in the lake to produce the observed data. Explain also how these processes would account for your prediction of results for a heavily overcast day.

(c) Describe how the introduction of high levels of nutrients such as nitrates and phosphates into the lake would affect subsequent observations. Explain your prediction.

 

2001 All Questions     Scoring Guidelines     Scoring Commentary     Sample Responses Q4
2001 #4
 Proteins-large complex molecules-are major building blocks of all living organisms. Discuss the following in relation to proteins.
(a) The chemical composition and levels of structure of proteins
(b) The roles of DNA and RNA in protein synthesis
(c) The roles of proteins in membrane structure and transport of molecules across the membrane

 

2000

2000 All Questions         Scoring Guidelines           Sample Responses Q1

1. The effects of pH and temperature were studied for an enzyme-catalyzed reaction. The following results were obtained.

a)     How do (1) temperature and (2) pH affect the activity of this enzyme? In your answer, include a discussion of the relationship between the structure and the function of this enzyme, as well as a discussion of how structure and function of enzymes are affected by temperature and pH.

b) Describe a controlled experiment that could have produced the data shown for either temperature or pH. Be sure to state the hypothesis that was tested here.

2000 All Questions         Scoring Guidelines       Sample Responses Q2

2000 #2.
Feedback mechanisms are used by organisms to maintain the steady-state physiological condition known
as homeostasis. Choose three of the following and for each, explain how feedback mechanisms maintain homeostasis.
a)    Blood glucose concentration.
b)  Calcium ion concentration in blood.
c)    Body temperatures in mammals.
d)  Osmolarity of the blood.
e)    
Pulse rate in mammals.

2000 All Questions         Scoring Guidelines        Sample Responses Q3

2000 #3
.
 Information transfer is fundamental to all living organisms. For two of the following examples, explain in detail
how the transfer of information is accomplished.
a)   The genetic material in one eukaryotic cell is copied and distributed to two identical daughter cells
b) A gene in a eukaryotic cell is transcribed and translated to produce a protein
c)  The genetic material from one bacterial cell enters another via transformation, transduction, or conjugation

2000 All Questions         Scoring Guidelines        Sample Responses Q4

2000 #4
To survive, organisms must be capable of avoiding, and/or defending against, various types of environmental
threats. Respond to each of the following.
    a) Describe how adaptive coloration, mimicry, or behavior function as animal defenses against predation.
   
   Include two examples in your answer.
    b) Describe how bacteria or plants protect themselves against environmental threats.
        Include two examples in
your answer.
    c) Compare the human primary immune response with the secondary immune response to the same antigen.


1999

1999 All Questions         Scoring Guidelines       Sample Responses Q1

1999 #1
The rate of photosynthesis may vary with changes that occur in environmental temperature, wavelength of light, and light intensity.  Using a photosynthetic organism of your choice, choose only ONE of the three variables (temperature, wavelength of light, or light intensity) and for this variable
    
 • DESIGN a scientific experiment to determine the effect of the variable on the rate of photosynthesis for the organism.
      • EXPLAIN how you would measure the rate of photosynthesis in your experiment
    
 • DESCRIBE the results you would expect. EXPLAIN why you would expect these results.

 

1999 All Questions         Scoring Guidelines                Sample Responses Q2

1999 #2.
Communication occurs among the cells in a multicellular organism. Choose THREE of the following examples of cell-to-cell communication, and for each example, describe the communication that occurs and the types
of responses that result from this communication.
  
•  Communication between two plant cells
   •  Communication between two immune-system cells
   •  Communication either between a neuron and another neuron, or between a neuron and a muscle cell
   •  Communication between a specific endocrine-gland cell and its target cell

1999 All Questions     Scoring Guidelines        Sample Responses Q3

1999 #3.
Scientists recently have proposed a reorganization of the phylogenetic system of classification to include the
domain, a new taxonomic category higher (more inclusive) than the Kingdom category, as shown in the following diagram.

  

•  Describe how this classification scheme presents different conclusions about the relationships among living organisms than those presented by the previous five-kingdom system of classification.

•  Describe three kinds of evidence that were used to develop the taxonomic scheme above, and explain how this evidence was used. The evidence may be structural, physiological, molecular, and/or genetic.

•  Describe four of the characteristics of the universal ancestor.

1999 All Questions       Scoring Guidelines             Sample Responses Q4

1999 #4.
Scientists seeking to determine which molecule is responsible for the transmission of characteristics from one generation to the next knew that the
molecule must
    
(1) copy itself precisely
     (2) be stable but able to be changed
     (3) be complex enough to determine the organism's phenotype
EXPLAIN how DNA meets each of the three criteria stated above
Select ONE of the criteria stated above and DESCRIBE experimental evidence used to determine that DNA is the hereditary material

 

The following is a comprehensive list of essay questions that have been asked on past AP exams. The questions are organized according to units covered in this class.

AP Biology Essay Questions

Unit 1 (Basic Chemistry and Water)

1.  The unique properties (characteristics) of water make life possible on Earth. Select three properties of water and:

    1. for each property, identify and define the property and explain it in terms of the physical/chemical nature of water.
    2. for each property, describe one example of how the property affects the functioning of living organisms.

 

Unit 2 (Organic Chemistry, Biochemistry, and Metabolism)

2.  Describe the chemical composition and configuration of enzymes and discuss the factors that modify enzyme structure and/or function.

3.  After an enzyme is mixed with its substrate, the amount of product formed is determined at 10-second intervals for 1 minute. Data from this experiment are shown below:

    Time (sec)

    0

    10

    20

    30

    40

    50

    60

    Product formed (mg)

    0.00

    0.25

    0.50

    0.70

    0.80

    0.85

    0.85

    Draw a graph of these data and answer the following questions.

    1. What is the initial rate of this enzymatic reaction?
    2. What is the rate after 50 seconds? Why is it different from the initial rate?
    3. What would be the effect on product formation if the enzyme where heated to a temperature of 100° C for 10 minutes before repeating the experiment? Why?
    4. How might altering the substrate concentration affect the rate of the reaction? Why?
    5. How might altering the pH affect the rate of the reaction? Why?

4.  Enzymes are biological catalysts.

    1. Relate the chemical structure of an enzyme to its specificity and catalytic activity.
    2. Design a quantitative experiment to investigate the influence of pH or temperature on the activity of an enzyme.
    3. Describe what information concerning the structure of an enzyme could be inferred from your experiments.

 

 

 

Unit 3 (Cell Structure and Function, Cell division)

5.  Describe the fluid-mosaic model of a plasma membrane. Discuss the role of the membrane in the movement of materials through it by each of the following processes:

    1. Active transport
    2. Passive transport

6.  Describe the structure of a eukaryotic plant cell. Indicate the ways in which a nonphotosynthetic prokaryotic cell would differ in structure from this generalized eukaryotic plant cell.

7.  Discuss the process of cell division in animals. Include a description of mitosis and cytokinesis, and of the other phases of the cell cycle. Do Not include meiosis.

     

8.  A laboratory assistant prepared solution of 0.8 M, 0.6 M, 0.4 M, and 0.2 M sucrose, but forgot to label them. After realizing the error, the assistant randomly labeled the flasks containing these four unknown solutions as flask A, flask B, flask C, and flask D.

    Design an experiment, based on the principles of diffusion and osmosis, that the assistant could use to determine which of the flasks contains each of the four unknown solutions. Include in your answer (a) a description of how you would set up and perform the experiment: (b) the results you would expect from your experiments: and (c) an explanation of those results based on the principles involved. (Be sure to clearly state the principles addressed in your discussion.)

9.  Cells transport substances across their membranes. Choose THREE of the following four types of cellular transport.

    • Osmosis
    • Active Transport
    • Facilitated Diffusion
    • Endocytosis/exocytosis

For each of the three transport types you choose,

    1. Describe the transport process and explain how the organization of cell membranes functions in the movement of specific molecules across membranes; and
    2. Explain the significance of each type of transport to a specific cell (you may use difference cell types as examples.)

Unit 4 (Photosynthesis and Cellular Respiration)

10.  Describe the similarities and differences between the biochemical pathways of aerobic respiration and photosynthesis in eukaryotic cells. Include in your discussion the major reactions, the end products, and energy transfers.

11.  The rate of photosynthesis may vary with changes that occur in environmental temperature, wavelength of light, and light intensity. Using a photosynthetic organism of your choice, choose only ONE of the three variables (temperature, wavelength of light, or light intensity) and for this variable

    • design a scientific experiment to determine the effect of the variable on the rate of photosynthesis for the organism;
    • explain how you would measure the rate of photosynthesis in your experiment;
    • describe the results you would expect. Explain why you would expect these results.

12.  Describe the light reactions of photosynthesis and, for both a C3 and a C4 plant, trace the path of a carbon dioxide molecule from the point at which it enters a plant to its incorporation into a glucose molecule. Include leaf anatomy and biochemical pathways in your discussion of each type of plant.

13.  Explain what occurs during the Krebs (citric acid) cycle and electron transport by describing the following:

    1. The location of the Krebs cycle and electron transport chain in mitochondria.
    2. The cyclic nature of the reactions in the Krebs cycle.
    3. The production of ATP and reduced coenzymes during the cycle.
    4. The chemiosmotic production of ATP during electron transport.

14.  Membranes are important structural features of cells.

    1. Describe how membrane structure is related to the transport of materials across the membrane.
    2. Describe the role of membranes in the synthesis of ATP in either cellular respiration or photosynthesis.

15. Energy transfer occurs in all cellular activities. For 3 of the following 5 processes involving energy transfer, explain how each functions in the cell and give an example. Explain how ATP is involved in each example you choose.

        • cellular movement
        • active transport
        • synthesis of molecules
        • chemiosmosis
        • fermentation

16. The results below are measurements of cumulative oxygen consumption by germinating and dry seeds. Gas volume measurements were corrected for changes in temperature and pressure.

    Cumulative Oxygen Consumed (mL)

    Time (minutes)

    0

    10

    20

    30

    40

    22° C Germinating Seeds

    0.0

    8.8

    16.0

    23.7

    32..0

    Dry Seeds

    0.0

    0.2

    0.1

    0.0

    0.1

    10° C Germinating Seeds

    0.0

    2.9

    6.2

    9.4

    12.5

    Dry Seeds

    0.0

    0.0

    0.2

    0.1

    0.2

    1. Using the graph paper provided, plot the results for the germinating seeds at 22° C and at 10° C.
    2. Calculate function the rate of oxygen consumption for the germinating seeds at 22° C, using the time interval between 10 and 20 minutes.
    3. Account for the differences in oxygen consumption observed between:
      1. germinating seeds at 22° C and at 10° C
      2. germinating seeds and dry seeds
    4. Describe the essential features of an experimental apparatus that could be used to measure oxygen consumption by a small organism. Explain why each of these features is necessary.

    Unit 5 (Meiosis, Mendelian Genetics, DNA Replication)

17.  State the conclusions reached by Mendel in his work on the inheritance of characteristics. Explain how each of the following deviates from these conclusions.

    1. Autosomal linkage.
    2. Sex-linked (X-linked) inheritance.
    3. Polygenic (multiple-gene) inheritance.

18.  Experiments by the following scientists provided critical information concerning DNA. Describe each classical experiment and indicate how it provided evidence for the chemical nature of the gene.

    1. Hershey and Chase- bacteriophage replication
    2. Griffith and Avery, MacLeod and McCarty- bacterial transformation
    3. Meselson and Stahl- DNA replication in bacteria

19.  Discuss Mendel’s laws of segregation and independent assortment. Explain how the events of meiosis I account for the observations that led Mendel to formulate these laws.

20.  An organism is heterozygous at two genetic loci on different chromosomes.

    1. Explain how these alleles are transmitted by the process of mitosis to daughter cells.
    2. Explain how these alleles are distributed by the process of meiosis to gametes.
    3. Explain how the behavior of these two pairs of homologous chromosomes during meiosis provides the physical basis for Mendel’s two laws of inheritance.

    Labeled diagrams that are explained in your answer may be useful.

    Unit 6 (Protein Synthesis, Gene Expression, DNA Technology)

21.  A portion of specific DNA molecule consists of the following sequence of nucleotide triplets.

    TAC GAA CTT GGG TCC

    This DNA sequence codes for the following short polypeptide.

    methionine - leucine - glutamic acid - proline - arginine

    Describe the steps in the synthesis of this polypeptide. What would be the effect of a deletion or an addition in one of the DNA nucleotides? What would be the effects of a substitution in one of the nucleotides?

22.  Describe the operon hypothesis and discuss how it explains the control of messenger RNA production and the regulation of protein synthesis in bacterial cells.

23.  Scientists seeking to determine which molecule is responsible for the transmission of characteristics from one generation to the next knew that the molecule must (1) copy itself precisely, (2) be stable but able to be changed, and (3) be complex enough to determine the organism’s phenotype.

  • Explain how DNA meets each of the three criteria stated above.
  • Select one of the criteria stated above and describe experimental evidence used to determine that DNA is the hereditary material.

 

24.  Describe the biochemical composition, structure, and replication of DNA. Discuss how recombinant DNA techniques may be used to correct a point mutation.

25.  Describe the production and processing of a protein that will be exported from a eukaryotic cell. Begin with the separation of the messenger RNA from the DNA template and end with the release of the protein at the plasma membrane.

26.  Describe the steps of protein synthesis, beginning with the attachment of a messenger RNA molecule to the small subunit of a ribosome and ending generalized with the release of the polypeptide from the ribosome. Include in your answer a discussion of how the different types of RNA function in this process.

27.  The diagram below shows a segment of DNA with a total length of 4,900 base pairs. The arrows indicate reaction sites for two restriction enzymes (enzyme X and enzyme Y).

    1. Explain how the principles of gel electrophoresis allow for the separation of DNA fragments.
    2. Describe the results you would expect from the electrophoresis separation of fragments from the following treatments of the DNA segment above. Assume that the digestions occurred under appropriate conditions and went to completion.
      1. DNA digested with only enzyme X
      2. DNA digested with only enzyme Y
      3. DNA digested with enzyme X and enzyme Y combined
      4. Undigested DNA
    3. Explain both of the following.
      1. The mechanism of action of restriction enzymes.
      2. The different results you would expect if a mutation occurred at the recognition site for enzyme Y.

28.  By using the techniques of genetic engineering, scientists are able to modify genetic materials so that a particular gene of interest from one cell can be incorporated into a different cell.

        • Describe a procedure by which this can be done.
        • Explain the purpose of each step of your procedure.
        • Describe how you could determine whether the gene was successfully incorporated.
        • Describe an example of how gene transfer and incorporation have been used in biomedical or commercial applications.

29.  Assume that a particular genetic condition in a mammalian species causes an inability to digest starch. This disorder occurs with equal frequency in males and females. In most cases, neither parent of affected offspring has the condition.

    1. Describe the most probable pattern of inheritance for this condition. Expalin your reasoning. Include in your discussion a sample cross(es) sufficient to verify your proposed pattern.
    2. Explain how a mutation could cause this inability to digest starch.
    3. Describe how modern techniques of molecular biology could be used to determine whether the mutant allele is present in a given individual.

     

29.  Describe the special relationship between the two terms in each of the following pairs.

    1. Convergent evolution of organisms and Australia.
    2. Blood groups and genetic drift.
    3. Birds of prey and DDT.

30.  Describe the modern theory of evolution and discuss how it is supported by evidence from two of the following areas.

    1. population genetics
    2. molecular biology
    3. comparative anatomy and embryology

31.  Describe the process of speciation. Include in your discussion the factors that may contribute to the maintenance of genetic isolation.

32.  Do the following with reference to the Hardy-Weinberg model.

    1. Indicate the conditions under which allelic frequencies (p and q) remain constant from one generation to the next.
    2. Calculate, showing all work, the frequencies of the alleles and the frequencies of the genotypes in a population of 100,000 rabbits, of which 25,000 are white and 75,000 are agouti. (In rabbits the white color is due to a recessive allele, w, and the agouti is due to a dominant all, W.)
    3. If the homozygous dominant condition were to become lethal, what would happen to the allelic and genotypic frequencies in the rabbit population after two generations?

33.  Evolution is one of the major unifying themes of modern biology.

    1. Explain the mechanisms that lead to evolutionary change.
    2. Describe how scientists use each of the following as evidence for evolution.
      1. Bacterial resistance to antibodies.
      2. Comparative biochemistry.
      3. The fossil record.

34.  Genetic variation is the raw material for evolution.

    1. Explain three cellular and/or molecular mechanisms that introduce variation into the gene pool of a plant or animal population.
    2. Explain the evolutionary mechanisms that can change the composition of the gene pool.

35.  In a laboratory population of diploid, sexually reproducing organisms a certain trait is studied. This trait is determined by a single autosomal gene and is expressed as two phenotypes. A new population was created by crossing 51 purebreeding (homozygous) dominant individuals with 49 pure breeding (homozygous) individuals. After four generations, the following results were obtained.

    Number of Individuals

    Generation

    Dominant

    Recessive

    Total

    1

    51

    49

    100

    2

    280

    0

    280

    3

    240

    80

    320

    4

    300

    100

    400

    5

    360

    120

    480

    1. Identify an organism that might have been used to perform this experiment, and explain why this organism is a good choice for conducting this experiment.
    2. On the basis of the data, propose a hypothesis that explains the change in phenotypic frequency between generation 1 and generation 3.
    3. Is there evidence indicating whether or not this population is in Hardy-Weinberg equilibrium? Explain.

 Unit 8 (Chemical Evolution, Prokaryotes, Eukaryote Evolution, Protista)

36.  Scientists recently have proposed a reorganization of the phylogenetic system of classification to include the domain, a new taxonomic category higher (more inclusive) than the Kingdom category, as shown in the following diagram.

Universal Ancestor

Domain Bacteria             Domain Archaea Domain Eukarya

(Eubacteria)             (Archaebacteria) (Eukaryotes)

 

    • describe how this classification scheme presents different conclusions about the relationships among living organisms than those presented by the previous five-kingdom system of classification
    • describe three kinds of evidence that were used to develop the taxonomic scheme above, and explain how this evidence was used. The evidence may be structural, physiological, molecular, and/or genetic.
    • Describe four of the characteristics of the universal ancestor.

Unit 9 (Introduction to Plants, Fungi, Invertebrates)

37.  In the life cycles of a fern and a flowering plant, compare and contrast each of the following:

    1. The gametophyte generation.
    2. Sperm transport and fertilization.
    3. Embryo protection.

38.  Describe the differences between the terms in each of the following pairs.

    1. Coelomate versus acoelomate body plan.
    2. Protostome versus deuterostome development.
    3. Radial versus bilateral symmetry.
    4. Explain how each of these pairs of features was important in constructing the phylogenetic tree shown below. Use specific examples from the tree in your discussion.

    Unit 10 (Vertebrates, Basic Animal Structure and Function)

39.  Select two of the following three pairs and discuss the evolutionary relationships between the two members of each pair you have chosen. In your discussion include structural adaptations and the functional significance.

    Pair A: green algae---vascular plants

    Pair B: prokaryotes---eukaryotes

    Pair C: amphibians---reptiles

    Unit 11 (Animal Nutrition, Circulation, Respiration, Immune System)

40.  Describe the structure of a mammalian respiratory system. Include in your discussion the mechanisms of inspiration and expiration.

41.  Describe the processes of fat and protein digestion and product absorption as they occur in the human stomach and small intestine. Include a discussion of the enzymatic reactions involved.

42.  Describe the following mechanisms of response to foreign materials in the human body.

    1. The antigen-antibody response to a skin graft from another person.
    2. The reactions of the body leading to inflammation of a wound infected by bacteria.

43.  Discuss the processes of exchange of O2 and CO2 that occur at the alveoli and muscle cells of mammals. Include in your answer a description of the transport of these gases in the blood.

44.  Many physioligical changes occur during exercise.

    1. Design a controlled experiment to test the hypothesis that an exercise session causes short-term increases in heart rat and breathing rate in humans.
    2. Explain how at least three organ systems are affected by this increased physical activity and discuss interactions among these systems.

45.  The graph below shows the response of the human immune system to exposure to an antigen. Use this graph to answer part a and part b of this question.

    1. Describe the events that occur during period I as the immune system responds to the initial exposure to the antigen.
    2. Describe the events that occur during period II following a second exposure to the same antigen.
    3. Explain how infection by the AIDS virus (HIV) affects the function of both T and B lymphocytes.

    Unit 12 (Homeostasis, Reproduction, Development)

47.  Discuss the processes of cleavage, gastrulation, and neurulation in the frog embryo; tell what each process accomplishes. Describe an experiment that illustrates the importance of induction in development.

48.  The evolutionary success of organisms depends on reproduction. Some groups of organisms reproduce asexually, some reproduce sexually, while others reproduce both sexually and asexually.

    1. Using THREE difference organisms, give an example of one organism that reproduces sexually, one that reproduces asexually, and one that reproduces BOTH sexually and asexually. For each organism given as an example, describe two reproductive adaptations. These adaptations may be behavioral, structural, and/or functional.
    2. What environmental conditions would favor sexual reproduction? Explain. What environmental conditions would favor asexual reproduction? Explain.

    Unit 13 (Endocrine System, Nervous System, Sensory and Motor Mechanisms)

49.  Discuss the sources and actions of each of the following pairs of hormones in humans and describe the feedback mechanisms that control their release.

    1. Insulin---glucagon
    2. Parathyroid hormone---calcitonin
    3. Thyrotropin (TSH)---thyroxine (T4)

50.  Beginning at the presynaptic membrane of the neuromuscular junction, describe the physical and biochemical events involved in the contraction of a skeletal muscle fiber. Include the structure of the fiber in your discussion.

52.  Describe the negative and positive feedback loops, and discuss how feedback mechanisms regulate each of the following.

    1. The menstrual cycle in nonpregnant human female.
    2. Blood glucose levels in humans.

53.  Discuss how cellular structures, including the plasma membrane, specialized endoplasmic reticulum, cytoskeletal elements, and mitochondria, function together in the contraction of skeletal muscle cells.

54.  Structure and function are related in the various organ systems of animals.

Select two of the following four organ systems in vertebrates:

    • respiratory
    • digestive
    • excretory
    • nervous

For each of the two systems you choose, discuss the structure and function of two adaptations that aid in the transport or exchange of molecules (or ions). Be sure to relate structure to function in each example.

Unit 14 (Plant Structure and Function)

55.  Relate the structure of an angiosperm leaf to each of the following:

    1. Adaptations for photosynthesis and food storage.
    2. Adaptations for food translocation and water transport.
    3. Specialized adaptations to a desert environment.

56.  Define the following plant responses and explain the mechanism of control for each. Cite experimental evidence as part of your discussion.

    1. Phototropism
    2. Photoperiodism

57.  Describe the structure of a bean seed and discuss its germination to the seedling stage. Include in your essay hormonal controls, structural changes, and tissue differentiation.

58.  Describe the effects of plant hormones on plant growth and development. Design an experiment to demonstrate the effect of one of these plant hormones on plant growth and development.

59.  Trace the pathway in a flowering plant as the water moves from the soil through the tissues of the root, stem, and leaves to the atmosphere. Explain the mechanisms involved in conducting water through these tissues.

60.  Discuss the adaptations that have enabled flowering plants to overcome the following problems associated with life on land.

    1. The absence of an aquatic environment for reproduction.
    2. The absence of an aquatic environment to support the plant body.
    3. Dehydration of the plant.

61.  A group of students designed an experiment to measure transpiration rates in a particular species of herbaceous plant. Plants were divided into four groups and were exposed to the following conditions.

    Group I- Room conditions (light, low humidity, 20° C, and little air movement.)
    Group II- Room conditions with increased humidity.
    Group III- Room conditions with increased air movement (fan)
    Group IV- Room conditions with additional light

    The cumulative water loss due to transpiration of water from each plant was measured at 10-minute intervals for 30 minutes. Water loss was expressed as milliliters of water per square centimeter of leaf surface area. The data for all plants in Group I (room conditions) were averaged. The average cumulative water loss by the plants in Group I is presented in the table below.

    Average Cumulative Water Loss by the Plants in Group I

    Time (minutes)

    Average Cumulative Water Loss (milliliter H2O centimeter2)

    10

    3.5 x 10-4

    20

    7.7 x 10-4

    30

    10.6 x 10-4

    1. Construct and label a graph using the data for Group I. Using the same set of axes, draw and label three additional lines representing the results that you would predict for Groups II, III, and IV.
    2. Explain how biological and physical processes are responsible for the difference between each of your predictions and the data for Group I.
    3. Explain how the concept of water potential is used to account for the movement of water from the plant stem to the atmosphere during transpiration.

62.  Numerous environmental variables influence plant growth. Three students each planted a seedling of the same genetic variety in the same type of container with equal amounts of soil from the same source. Their goal was to maximize their seedling’s growth by manipulating environmental conditions. Their data are shown below.

    Plant Seedling Mass (grams)
    Day 1 Day 30
    Student A 4 24
    Student B 5 35
    Student C 4 64
    1. Indentify three different environmental variables that could account for differences in the mass of seedlings at day 30. Then choose one of these variables and design an experiment to test the hypothesis that your variable affects growth of these seedlings.
    2. Discuss the results you would expect if your hypothesis is correct. Then provide a physiological explanation for the effect of your variable on plant growth.

    Unit 15 (Ecology)

63.  Define and explain the role of each of the following in social behavior.

    1. Territoriality.
    2. Dominance hierarchies.
    3. Courtship behavior.

64.  Describe the trophic levels in a typical ecosystem. Discuss the flow of energy through the ecosystem, the relationship between the different trophic levels, and the factors that limit the number of trophic levels.

65.  Describe and give an example of each of the following. Include in your discussion the selection advantage of each.

    1. Pheromones.
    2. Mimicry.
    3. Stereotyped behavior (instinct).

66.  Describe the process of ecological succession from a pioneer community to a climax community. Include in your answer a discussion of species diversity and interactions, accumulation of biomass, and energy flow.

67.  Describe releasers, imprinting, and communications, as each of these terms relates to animal behavior. You may include in your answer a discussion of the classical studies of Nikolaas Tinbergen, Konrad Lorenz, and Karl von Frisch.

68.  Describe the biogeochemical cycles of carbon and nitrogen. Trace these elements from the point of their release from a decaying animal to their incorporation into a living animal.

69.  Using an example for each, discuss the following ecological concepts.

    1. Succession
    2. Energy flow between trophic levels.
    3. Limiting factors.
    4. Carrying capacity.

 

70.  Living organisms play an important role in the recycling of many elements within an ecosystem. Discuss how various types of organisms and their biochemical reactions contribute to the recycling of either carbon or nitrogen in an ecosystem. Include in your answer one way in which human activity has an impact in the nutrient cycle you have chosen.

71.  Survival depends on the ability of an organism to respond to changes in its environment. Some plants flower in response to changes in day length. Some mammals may run or fight when frightened. For both of these examples, describe the physiological mechanisms involved in the response.

72.  Interdependence in nature is illustrated by the transfer of energy through trophic levels. The diagram below depicts the transfer of energy in a food web of an Arctic lake located in Alaska (J )

    1. Choosing organisms from four different trophic levels of this food web as examples, explain how energy is obtained at each trophic level.
    2. Describe the efficiency of energy transfer between trophic levels and discuss how the amount of energy available at each trophic level affects the structure of the ecosystem.
    3. If the cells in the dead terrestrial plant material that washed into the lake contained a commercially produced toxin, what would be the likely effects of this toxin on this food web? Explain

     

73.  A scientist working with Bursatella leachii, a sea slug that lives in an intertidal habitat in the coastal waters of Puerto Rico, gathered the following information about the distribution of the sea slugs within a ten-meter square plot over a 10-day period.

    Distribution of Slugs within a ten-meter square plot

    Time of Day

    Average Distance between individuals (cm)

    Midnight

    8.0

    4 a.m.

    8.9

    8 a.m.

    44.8

    Noon

    174.0

    4 p.m.

    350.5

    8 p.m.

    60.5

    midnight

    8.0

For the data above, provide information on each of the following.

    • Summarize the pattern.
    • Identify THREE physiological or environmental variables that could cause the slugs to vary their distance from each other.
    • Explain how each variable could bring about the observed pattern of distribution.

Choose ONE of the variables that you identified and design a controlled experiment to test your hypothetical explanation. Describe results that would support or refute your hypothesis.

Cummulative Essays

74.  Describe how the following adaptations have increased the evolutionary success of the organisms that possess them. Include in your discussion the structure and function related to each adaptation.

    1. C4 metabolism
    2. Amniotic egg
    3. Four-chambered heart
    4. Pollen

75.  Describe the anatomical and functional similarities and difference within each of the following pairs of structures.

    1. Artery---vein
    2. Small intestine---colon
    3. Skeletal muscle---cardiac muscle
    4. Anterior pituitary---posterior pituitary

76.  Discuss how each of the following has contributed to the evolutionary success of the organisms in which they are found.

    1. seeds
    2. mammalian placenta
    3. diploidy

77.  Angiosperms (flowering plants) and vertebrates obtain nutrients from their environment in different ways.

    1. Discuss the type of nutrition and the nutritional requirements of angiosperms and vertebrates.
    2. Describe 2 structural adaptations in angiosperms for obtaining nutrients from the environment. Relate structure to function.
    3. Interdependence in nature is evident in symbiosis. Explain tow symbiotic relationships that aid in nutrient uptake, using examples from angiosperms and/or vertebrates. (Both examples may be angiosperms, both may be vertebrates, or one may be from each group.

78.  The problem of survival of animals on land are very different from those of survival of animals in an aquatic environment. Describe four problems associated with animal survival in terrestrial environments but not in aquatic environments. For each problem, explain an evolutionary solution.

79.  The survival of organisms depends on regulatory mechanisms at various levels. Choose THREE from the following examples. Explain how each is regulated.

    • The expression of a gene.
    • The activity of an enzyme.
    • The cell cycle.
    • The internal water balance of a plant.
    • The density of a population.

80.  Photosynthesis and cellular respiration recycle oxygen in ecosystems. Respond to TWO (and only two) of the following:

    1. Explain how the metabolic processes of cellular respiration and photosynthesis recycle oxygen.
    2. Discuss the structural adaptations that function in oxygen exchange between each of the following organisms and its environment: a plant; an insect; a fish.
    3. Trace a molecule of O2 from the environment to a muscle cell in a vertebrate of your choice.

81.  Biological recognition is important in many processes at the molecular, cellular, tissue, and organismal levels. Select three of the following, and for each of the three that you have chose, explain how the process of recognition occurs and give an example of each.

    1. Organisms recognize others as members of their own species.
    2. Neurotransmitters are recognized in the synapse.
    3. Antigens trigger antibody response.
    4. Nucleic acids are complementary.
    5. Target cells respond to specific hormones.

82.  Communication occurs among the cells in a multicellular organism. Choose THREE of the following examples of cell-to-cell communication, and for each example, describe the communication that occurs and the types of responses that result from this communication.

  • communication between two plant cells
  • communication between two immune-system cells
  • communication either between a neuron and another neuron, or between a neuron and a muscle cell
  • communication between a specific endocrine-gland cell and its target cell