Free Response Questions 14 Full Questions

2006: Cell Structure and Function A major distinction between prokaryotes and eukaryotes is the presence of membrane- bound organelles in eukaryotes.

Prokaryotic and eukaryotic cells have some non- membrane-bound components in common. Describe the function of TWO of the following and discuss how each differs in prokaryotes and eukaryotes. DNA Cell Wall Ribosomes

Explain the endosymbiotic theory of the origin of eukaryotic cells and discuss an example supporting this theory.

2006 B: Structure and Function The relationship of structure to 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.

Enzyme structure/catalysis

mRNA structure/catalysis

Cell membrane structure/signal transduction

Membrane protein structure/active transport or facilitative diffusion

2011 Exam: Water Potential and Transpiration

Identify and explain THREE different structural or physiological adaptations that could account for the different transpiration rates of species A and B.

Water potential (Ψ) is described by the following formulas. Discuss the variables in both formulas and how they affect water potential.

2006 B: Transpiration

Identify how two different environmental factors could be involved in the daily fluctuations shown above.

Discuss the mechanisms involved in the uptake and transport of water by vascular plants.

Discuss the role of water in the normal functioning of plants.

2009 Exam: Metabolism 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 at each level of this pyramid. 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.

Describe the structure of the ATP or the GTP molecule.

Explain how chemiosmosis produces ATP.

Classical Genetics: 2010 Exam, Q3 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 the resulting offspring were recorded. Cross I: True-breeding bronze-eyed males were crossed with true-breeding red-eyed females. All the F1offspring had bronze eyes. F1 flies were crossed, and the data for the resulting F2 flies are given in the table below.

Cross II: True-breeding normal-winged males were crossed with true-breeding stunted- winged females. All the F1 offspring had stunted wings. F1 flies were crossed, and the data for the resulting F2 flies are given in the table below.

Cross III: True-breeding bronze-eyed, stunted- winged males were crossed with true- breeding red-eyed, normal winged females. All the F1 offspring had bronze eyes and stunted wings. The F1 flies were crossed with true breeding red-eyed, normal-winged flies, and the results are shown in the table below.

What conclusions can be drawn from cross I and cross II? Explain how the data support your conclusions for each cross.

What conclusions can be drawn from the data from cross III? Explain how the data support your conclusions.

Identify and discuss TWO different factors that would affect whether the island’s fly population is in Hardy- Weinberg equilibrium for the traits above.

2012 Q3 DNA Processing 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 effect 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.

2007 B: Transcription and Translation 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 into 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?

2009 B Exam: Biotechnology 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.

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.

2007 Exam: Biotechnology

Using the circle provided, construct a labeled diagram of a restriction map of the plasmid. Explain how you developed your map.

Describe how: Recombinant DNA technology can be used to insert a gene of interest into a bacterium

Describe how: Recombinant bacteria could be identified

Describe how: Expression of a gene of interest could be insured

2006 Exam: Population Biology According to fossil records and recent published observations, two species of leaf-eating beetles (species A and B) have existed on an isolated 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 population size of each species has been regularly monitored as shown in the graph above.

Propose an explanation for the pattern of population density observed in species C.

Describe the effect that the introduction of beetle species C has had on the population density of species A and species B. Propose an explanation for the patterns of population density observed in species A and in species B.

Predict the population density of species C in Provide a biological explanation for your prediction.

Explain why invasive species are often successful in colonizing new habitats.

2006 B Energy in Ecosystems 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.

Discuss the role of green plants in transforming the Sun’s energy into a form that can ultimately be used by heterotrophs.

Discuss the flow of energy from producers through top carnivores in a food web in terms of the laws of thermodynamics.

2010 B Ecology Experimental Design 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 that this factor affects the distribution of millipedes on the forest floor. Describe data that would support your hypothesis.

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.

2008 B: Hardy-Weinberg

What is the frequency of each genotype (AA, Aa, and aa) in this population? What is the frequency of the dominant phenotype?

How can the concept of Hardy-Weinberg equilibrium be used to determine whether this population is evolving?

Identify a particular environmental change and describe how it may alter allelic frequencies in this population. Explain which condition of Hardy-Weinberg equilibrium would not be met.

2011 exam, 3c Discuss TWO prezygotic isolating mechanisms that prevent hybridization between two species. Include in your discussion an example of each mechanism.