AP Bio Midterm Review
Which of the following cube-shaped cells would be most efficient in removing waste by diffusion?
10μm
Dialysis tubing is permeable to water molecules but not to sucrose. The masses of the dialysis tubes are recorded at 30-minute intervals for 90 minutes, as shown in the table below. The contents of which dialysis tube are initially isotonic to the distilled water in the beaker?
5
Dialysis tubing is permeable to water molecules but not to sucrose. The masses of the dialysis tubes are recorded at 30-minute intervals for 90 minutes, as shown in the table below. A net movement of water into the beaker occurs in which of the following dialysis tubes?
6
A common laboratory investigation involves putting a solution of starch and glucose into a dialysis bag and suspending the bag in a beaker of water, as shown in the figure below. Which of the following best represents the amount of starch, water, and glucose in the dialysis bag over the course of the investigation?
A
A student formulated a hypothesis that water-soluble pollutants damage living organisms by increasing the permeability of cellular membranes. Which of the following graphs is the most appropriate representation of the experimental data?
A
Sickle-cell anemia is associated with a mutation in the gene encoding the beta subunit of hemoglobin that results in a change from glutamic acid to valine at position 6. All other amino acids are identical to a normal hemoglobin molecule. Based on the information above, which of the following mutations is the most likely cause of sickle-cell anemia?
A single base-pair substitution in the gene encoding the beta subunit
Ascorbic acid (vitamin C) is an organic molecule necessary for the health of plants and animals. The majority of animals, including most mammals, synthesize ascorbic acid from organic precursors, but some primates are unable to synthesize ascorbic acid and must instead acquire it from dietary sources, such as certain fruits and vegetables. Comparison of DNA sequences in Table II suggests that a functional GULO gene in lemurs can have a G, C, or T at position 21 but only a G at position 22. Which of the following pairs of predictions is most helpful in explaining the discrepancy?
A substitution at position 21 would result in A substitution at position 22 would result in No change to the protein A premature stop codon or an amino acid with different biochemical characteristics
Gelatin is a protein that is derived from collagen which is found in the bones, skin, and connective tissue of animals. To investigate the ability of various enzymes to digest gelatin, a group of students set up an assay involving camera film. The students recorded the time it took for the enzymes to digest the gelatin in each test tube, turning the film from black to clear. Which of the following would be the most appropriate control for this experiment?
A test tube containing a piece of exposed camera film submerged in water
An investigator wants to understand whether a newly found membrane protein is involved in membrane transport of a certain particle. Which investigation will help determine whether the new membrane protein is a channel protein involved in membrane transport?
Add more of the proteins to the plasma membrane and measure the rate of the particle movement.
Which of the following best describes the numbered areas?
Areas 1 and 3 are polar, since the membrane molecules are aligned with water molecules.
Which of the following is an example of a density-independent limitation on a population?
At higher temperatures, more tomato plants in a population become infested with nematodes than at lower temperatures.
Alcohol dehydrogenase (ADH) is an enzyme that aids in the decomposition of ethyl alcohol (C2H5OH) into nontoxic substances. Methyl alcohol acts as a competitive inhibitor of ethyl alcohol by competing for the same active site on ADH. When attached to ADH, methyl alcohol is converted to formaldehyde, which is toxic in the body. Which of the following statements best predicts the effect of increasing the concentration of substrate (ethyl alcohol), while keeping the concentration of the inhibitor (methyl alcohol) constant?
Competitive inhibition will decrease because the proportion of the active sites occupied by substrate will increase.
Which of the following modifications of the DNA would produce the greatest change in the primary structure of the polypeptide chain?
Deleting the first T in the second triplet
Thrips are insects that feed on rose pollen. Scientists noted that the thrips population increased in the spring and decreased dramatically during the summer. The researchers hypothesized that food abundance was the limiting factor for the population. Which of the following types of data would be most useful for the scientists to collect at regular intervals on a designated test plot of rose plants?
Density of rose pollen produced (g/m2)
The population would be most likely to remain at the level shown at Q under which of the following conditions?
Environmental conditions do not fluctuate.
Which of the following statements best supports the claim that certain organelles within eukaryotic cells evolved from free-living prokaryotic cells?
Eukaryotes exchange segments of internal membranes between the endoplasmic reticulum and Golgi apparatus, but prokaryotes have no such internal membranes.
The diagram above shows the progression of ecological events after a fire in a particular ecosystem. Based on the diagram, which of the following best explains why the oak trees are later replaced by other trees?
Eventually the other trees grow taller than the oak trees and form a dense canopy that shades the understory.
A model that represents a process occurring in a cell of a particular organism is shown in Figure 1. Which of the following correctly explains the process shown in Figure 1 ?
Initiation of transcription is occurring because a strand of RNA is being produced from a DNA template strand.
A model of the plasma membrane showing several biological molecules, including a transmembrane protein, is shown in Figure 1. Which statement best explains why correct protein folding is critical in the transmembrane protein shown above?
Interactions of the hydrophobic and hydrophilic amino acids help to anchor the protein in the membrane.
Researchers studied the diversity of macroscopic invertebrates in different areas of watershed ecosystems. Which of the stream types had a statistically lower macroscopic invertebrate species diversity than the seasonal streams?
Intermittent streams only
Which of the following is most directly responsible for water's unique properties?
It forms hydrogen bonds.
Based on the universal genetic code, which of the following represents the correct polypeptide that will result from translation of the mRNA molecule shown, beginning with the first available start codon?
Met−Val−Thr−Lys−Phe−Gly−His
The manner in which several different ions and molecules move through a cell membrane is shown in the diagram above. For each ion or molecule, the relative concentration on each side of the membrane is indicated. Which of the following accurately describes one of the movements taking place?
Na+ transport out of the cell requires ATP hydrolysis.
Which of the following communities is likely to be most stable?
One with high species diversity
Membrane-bound organelles have been an important component in the evolution of complex, multicellular organisms. Which of the following best summarizes an advantage of eukaryotic cells having internal membranes?
Organelles isolate specific reactions, increasing metabolic efficiency.
Which of the following statements best explains the processes of passive and active transport?
Passive transport is the net movement of substances down a concentration gradient that does not require metabolic energy. Active transport is the movement of substances up a concentration gradient that requires energy.
Protein digestion in humans is primarily carried out by three enzymes. Graph 1 shows the effect of pH on the activity levels of the three enzymes. Which of the following best predicts how the structure and function of pepsin will change as it enters the small intestine?
Pepsin will change in shape because of the basic environment of the small intestine; therefore, its enzymatic activity will decrease.
Nuclear pores regulate the passage of substances into and out of the nucleus. Antibodies such as mAb414 have been used to inhibit the movement of substances through the nuclear pores of rat liver cells. Which of the following sets of graphs best summarizes the results of the experiments?
Prokaryotes are constant and go up; Eukaryotes are flat
A researcher claims that different enzymes exhibit maximal function over different pH ranges. Which of the following actions will provide the most appropriate negative control for the experiment?
Repeating the experiment with denatured enzymes
Erwin Chargaff investigated the nucleotide composition of DNA. He analyzed DNA from various organisms and measured the relative amounts of adenine (A), guanine (G), cytosine (C), and thymine (T) present in the DNA of each organism. Which of the following statements best explains the data set?
Since the %A and the %T are approximately the same in each sample, adenine and thymine molecules must pair up in a double-stranded DNA molecule.
Which of the following would be most appropriate for identifying the species with the most even distribution of nests?
Standard deviation of the nearest-neighbor distances for each species
Sickle-cell anemia is an inherited blood disorder in which one of the hemoglobin subunits is replaced with a different form of hemoglobin. Partial DNA sequences of the HBB gene for normal hemoglobin and for sickle-cell hemoglobin are shown in Figure 1. Which of the following best describes the type of mutation shown in Figure 1 that leads to sickle-cell anemia?
Substitution
Antibiotics interfere with prokaryotic cell functions. Streptomycin is an antibiotic that affects the small ribosomal subunit in prokaryotes. Which of the following best predicts the most direct effect of exposing prokaryotic cells to streptomycin?
Synthesis of polypeptides will be inhibited.
Based on the data in the table, which of the following best describes the habitat preference of T. atratus when introduced alone inside the meshed enclosure?
T. atratus exhibited a preference for the zones in or near water.
Based on the data in the table, which of the following best predicts the results of a study in which natural populations of T. atratus and T. sirtalis are observed together in an environment that includes a freshwater pond?
T. sirtalis will be observed near the water whether or not T. atratus is present.
Which of the following statements best describes how molecules released by the fish become nutrients for the plants?
The ammonia molecules released by the fish are converted by the bacteria to nitrates, which are used by the plants to make proteins and nucleic acids.
A scientist is evaluating a proposal for raising large numbers of fish in ocean pens for human consumption. Which of the following is the most appropriate factor to use as the dependent variable in the experimental investigation?
The amount of metabolic wastes in the water where the fish are being raised
Figure 1 represents part of a process essential to gene expression. Which of the following best explains what strand X represents?
The antisense strand, because it is serving as a template
A spherical bacterial cell has a radius of 3μm. The human egg cell has a radius of 100μm. Which statement correctly indicates the cell that is able to more efficiently exchange materials with the external environment and provides a correct explanation?
The bacterial cell, because it has the largest surface-to-volume ratio.
The following questions refer to an experiment in which a dialysis-tubing bag is filled with a mixture of 3% starch and 3% glucose and placed in a beaker of distilled water, as shown below. Which of the following best describes the condition expected after 24 hours?
The bag will contain more water than it did in the original condition.
In an experiment, the efficiency of oxygen exchange across the plasma membrane is being assessed in four artificial red blood cells. The table above lists some properties of those artificial cells. Other conditions being equal, which artificial cell is predicted to be the most efficient in exchanging oxygen with the environment by diffusion?
The cuboidal cell
Ascorbic acid (vitamin C) is an organic molecule necessary for the health of plants and animals. The majority of animals, including most mammals, synthesize ascorbic acid from organic precursors, but some primates are unable to synthesize ascorbic acid and must instead acquire it from dietary sources, such as certain fruits and vegetables. Which of the following is the most likely effect of the mutation at nucleotide position 7 in the GULO gene of humans?
The deletion of the single nucleotide causes a frame shift, changing the primary structure downstream of the mutation and resulting in a nonfunctional protein.
A researcher proposes a model of an enzyme-catalyzed reaction in which a reactant is converted to a product. Which of the following statements best helps explain how the enzyme speeds up the reaction?
The enzyme's active site binds to and stabilizes the transition state, which decreases the activation energy of the reaction.
Figure 1 represents part of a process that occurs in eukaryotic cells. There are untranslated regions (UTR) in this sequence. Which of the following best explains the process represented by Figure 1 ?
The enzyme-regulated processing of pre‑mRNA into mature mRNA
Which statement best explains the orientation of the phospholipid molecules in this model?
The hydrophilic phosphate groups of the phospholipid molecules are attracted to the aqueous internal and external environments.
A researcher designs an experiment to investigate the effect of environmental temperature on the function of an enzyme. Which of the following must remain the same for all trials of this experiment?
The initial concentration of the substrate
The figure shows a process by which a cell might absorb food from its surrounding environment and break it down for use as a source of energy and matter. Which of the following outcomes will most likely result from a loss of ion pump function in the cell's lysosomes?
The internal pH of the lysosomes will increase, which will prevent the activation of hydrolytic enzymes and interfere with the intracellular digestion of food.
Which of the following best predicts the results of a drought in the savanna research area with regards to community resilience to this environmental change?
The lightly grazed area is likely to recover more quickly from the drought due to greater biodiversity.
Based on the experimental results, which of the following statements best describes the relationship of the two populations that were studied in the investigation?
The populations have a competitive relationship in which each species limits the ability of the other to reproduce.
Which of the following statements best helps explain the reaction specificity of an enzyme?
The shape and charge of the substrates are compatible with the active site of the enzyme.
There is strong evidence that two species of cliff-dwelling birds have nested in the same environment and fed in the same water for thousands of years, with each having stable population sizes. Based on this information, which of the following statements is the best conclusion?
The two birds have different ecological niches that allow coexistence.
Molecular biologists are studying the processes of transcription and translation and have found that they are very similar in prokaryotes and eukaryotes, as summarized in Table 1. Based on the information in Table 1, which of the following best predicts a key difference in prokaryotes and eukaryotes with regard to transcription and translation?
The two processes will occur simultaneously in prokaryotes but not eukaryotes.
In an experiment, cells were isolated from an aquatic plant and suspended in pond water, a sucrose sugar solution, or distilled water. Which of the following statements best explains the observations represented in Figure 1 ?
There was a net movement of water out of the cell suspended in the sugar solution and a net movement of water into the cell suspended in the distilled water.
A sample of human blood was placed in a test tube containing a physiological saline solution (0.9% sodium chloride). Which of the following best predicts which diagrammed microscope view the laboratory worker would see and best explains why?
View 2 because the rate of water movement into the RBCs equals the rate of water movement out of the cells
A student formulated a hypothesis that water-soluble pollutants damage living organisms by increasing the permeability of cellular membranes. Based on the data from the investigation, which of the following is the best scientific question about organisms living in water that is polluted with organic solvents?
Will organisms living in polluted environments exhibit detrimental effects from an increased permeability of their cellular membranes?
Native to the Indian Ocean, C. taxifolia is known for aggressive growth and an ability to compete with sea grasses.It is currently on an international list of invasive species. Which of the following best predicts the consequences of the introduction of C. taxifolia to the California coast?
Without natural herbivores or competitors,C. taxifolia will grow rapidly and crowd out native species of producers.
A parasite may be described as an organism that derives nourishment from another living organism and
harms the host in the process
Sickle-cell anemia results from a point mutation in the HBB gene. The mutation results in the replacement of an amino acid that has a hydrophilic R-group with an amino acid that has a hydrophobic R-group on the exterior of the hemoglobin protein. Such a mutation would most likely result in altered
properties of the molecule as a result of abnormal interactions between adjacent hemoglobin molecules
All of the following are density-dependent factors that limit animal populations EXCEPT
weather
Which of the following models best predicts the effect on the ecosystem if a deadly communicable disease is introduced into the wolf population?
(A) Disease introduced: Wolf pop. goes down, Elk pop. goes up.
The enzyme peroxidase is found in many organisms. If the experiment is repeated at pH 11, the observed activity level of the enzyme will most likely be
lower than the level at pH 9
If a segment of DNA is 5'-TAC GAT TAG-3', the RNA that results from the transcription of this segment will be
3'-AUG CUA AUC-5'
Which of the following characteristics of Figure 1 best shows that the fragment is RNA and not DNA?
The identity of each nitrogenous base
Which of the following scientific questions is most relevant to the model represented in the figure above?
Which molecular substance is actively transported across the plasma membrane?
A researcher claims that increasing the environmental temperature by 10°C will double the rate of an enzyme-catalyzed reaction. For each test tube in the experiment, the researcher will measure the rate of product formation. Which of the following statements best helps justify the inclusion of test tube 5 as a control in the experiment?
It will provide a measurement of product formation in the presence of a denatured enzyme.
Amylase is a protein that catalyzes the conversion of starch to simple sugars. A student designs an experiment to investigate the effect of environmental pH on amylase function. The design of the experiment is presented in Table 1. Which of the following statements best justifies the inclusion of test tube V as a control in the experiment?
It will show the color change that occurs in the absence of enzyme activity.
Based on the data, which of the following is the best explanation for the changes in the elk population size between 2000 and 2005?
Predation by wolves was higher than before 1995.
Which of the following functional differences between the rough and smooth endoplasmic reticulum (ER) is explained by the structural differences between them?
Rough ER can synthesize and package proteins for export, and smooth ER cannot.
The figure above represents a rough endoplasmic reticulum. Which of the following best describes the role of the structure labeled Y?
Structure Y is the location where proteins are synthesized.
Researchers have proposed a model of the process by which a newly synthesized protein is transported to the plasma membrane and secreted into the extracellular space. Based on the model, the newly synthesized protein is transported directly from the endoplasmic reticulum to which of the following?
The Golgi complex
The figure above shows a series of microscope images taken over time of ovalbumin production in chick oviduct cells in response to stimulation with estrogen. The microscope images indicate that ovalbumin...
crosses the endoplasmic reticulum membrane as it is translated, then moves to the Golgi apparatus, then to vesicles from which it is secreted
Simple diffusion and facilitated diffusion are related in that both
depend on a concentration gradient
The graph indicates that the sheep population most likely is
stable after 1850 under the effects of density-dependent regulating factors
A researcher determines the rates of synthesis of several organic compounds found in the Spirogyra before and after several weeks in the water solution. Which of the following graphs best illustrates a likely result of the experiment?
(B) Carbohydrates, level and highest. Then, lipids, level.
Site of glucose synthesis
(B) Chloroplast
Site of modification and packaging of proteins and lipids prior to export from the cell
(C) Golgi Apparatus
A pathogenic bacterium has been engulfed by a phagocytic cell as part of the nonspecific (innate) immune response. Which of the following illustrations best represents the response?
(C) The one with Lysosomes
Which of the following graphs is most consistent with the claim that communities with high diversity are more resistant to change than are communities with low diversity?
(D) Downward Slope
Site of transport of materials into and out of the cell
(D) Plasma Membrane
Which of the following predictions about the community is most likely true?
A decrease in the wolf population will lead to a decrease in the mean aspen height.
Which of the following are characteristic of both prokaryotic and eukaryotic cells?
Cell membrane, ribosomes, DNA, and RNA
In which of the following would there NOT be a change in the amino acid sequence of the peptide coded for by this DNA?
Changing 3' AAA 5' to read 3' AAG 5'
Which point on the curve in the diagram above best represents the carrying capacity of the environment for the population shown?
E
Based on the data, which of the following behaviors in elk could account for the differences between the percent of aspens browsed by herbivores and the height of aspen trees in riparian and upland environments?
Elk tend to avoid riparian areas where the steep, wooded riverbanks make it difficult to escape predators.
If a dam is built downstream and prevents salmon migration to the test sites, which of the following most accurately predicts the impact on nitrogen influx?
Nitrogen influx will decrease because there will be less bear-salmon interaction.
Which of the following best describes an event during step 2 in the simplified model above?
Noncoding sequences are removed from a newly synthesized RNA molecule.
Researchers claimed that a particular organelle originated from a free-living prokaryotic cell that was engulfed by a larger cell, as shown in Figure 1. Which of the following provides evidence to best support the researchers' claim?
The organelle has a double membrane.
The synthesis of protein or carbohydrate polymers always produces which of the following as a byproduct?
Water
Used to carry the genetic code
nucleic acids
