ap biology midterm
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. The investigation is aimed at understanding how molecular size affects movement through a membrane. 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 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? A Interactions of the hydrophobic and hydrophilic amino acids help to anchor the protein in the membrane. B Interactions of the peptide bonds of the protein with the membrane will affect the rate at which substances can cross the membrane. C Interactions of the protein and phospholipids increase membrane fluidity. D Interactions of the quaternary structure of the protein will increase hydrogen bonding in the membrane and make the membrane less fluid.
A
A photosynthetic organism would be represented by which species? A A B B C C D D E E
A
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 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 B A substitution at position 21 would result in A substitution at position 22 would result in A different amino acid A premature stop codon or an amino acid with different biochemical characteristics C A substitution at position 21 would result in A substitution at position 22 would result in No change to the protein A frame shift producing an inactive protein D A substitution at position 21 would result in A substitution at position 22 would result in An amino acid with different biochemical characteristics No transcription of the gene
A
Evolved from a photoautotrophic prokaryote A A B B C C D D E E
A
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? A The cuboidal cell B The tetrahedral cell C The cylindrical cell D The spherical cell
A
In which of the following would there NOT be a change in the amino acid sequence of the peptide coded for by this DNA? A Changing 3' AAA 5' to read 3' AAG 5' B Changing 3' TTC 5' to read 3' ATC 5' C Changing 3' CCG 5' to read 3' GGC 5' D Deleting the first A from 3' AAA 5' E Deleting the last triplet
A
Site of conversion of chemical energy of glucose to ATP A A B B C C D D E E
A
The figure above shows an organelle typically found in eukaryotic cells. Which of the following best describes the function of the double membrane system of this organelle? A The outer membrane allows the transport of all molecules into the intermembrane space, while the inner membrane serves as the regulatory boundary. B The inner membrane has specialized proteins that create a hydrogen ion concentration gradient between the intermembrane space and the matrix. C The outer membrane contains transport proteins that establish a sodium ion concentration gradient used for ATP production, while the inner membrane contains transport proteins that establish a hydrogen ion concentration gradient used for glucose production. D The toxins and wastes entering a cell cross the outer membrane and are detoxified by digestive enzymes stored within the intermembrane space.
A
The figures can best assist in answering which of the following questions? A Do electron transport chains create a gradient so that ATP synthase can generate ATP molecules? B What are the sources of energy that drive mitochondrial and chloroplast electron transport systems? C What is the optimal temperature at which ATP synthase chemically converts ADP and a phosphate group into one molecule of ATP? D What is the evolutionary relationship between the ATP synthase in mitochondria and the ATP synthase in chloroplasts?
A
The maximum production rate of acetyl- under condition is closest to which of the following? A 1 macromolecule/min B 24 macromolecule/min C 35 macromolecule/min D 65 macromolecule/min
A
The rate of oxygen consumption in germinating pea seeds at 26ºC is A 0.05 mL / min B 0.25 mL / min C 0.50 mL / min D 0.75 mL / min E 1.00 mL / min
A
To investigate whether an organism in the study is capable of both photosynthesis and respiration, a comparison of which treatment groups is most appropriate? A I and II B II and IV C III and V D IV and VI
A
Which of the following best describes the numbered areas? A Areas 1 and 3 are polar, since the membrane molecules are aligned with water molecules. B Area 2 is polar, since water has been excluded from this area of the membrane. C Areas 1 and 3 are hydrophilic, since membrane molecules formed covalent bonds with water. D Area 2 is nonpolar, since hydrogen bonds between the adjacent lipids hold the membrane together.
A
Which of the following best explains how higher concentrations of nitrogen and phosphorus contribute to eutrophication? A An increase in the population of algae results in more nitrogen and phosphorus in the water, causing severe eutrophication. B Both bacteria and algae require nitrogen and phosphorus, so the algae must grow faster to compete with bacteria. C Nitrogen and phosphorus stimulate oxidative phosphorylation, which consumes the available oxygen in the water. D Algae require nitrogen and phosphorus to build macromolecules, so higher concentrations of these nutrients can result in algal blooms.
A
Which of the following best matches the fertilizer component with the molecule in which it will be incorporated by organisms in the area?A Nitrogen will be incorporated into nucleic acids. B Phosphorus will be incorporated into amino acids. C Potassium will be incorporated into lipids. D Magnesium will be incorporated into carbohydrates.
A
Which of the following best predicts the effect of not having available to supply energy to this process? A H+ ions will stop moving through the protein. B H+ ions will move in the other direction through the protein. C H+ ions will continue to move through the protein in the original direction but at a slower rate. D H+ ions will begin to move through the phospholipid portion of the membrane in the original direction.
A
Which of the following claims is best supported by the experimental results? A Light is required for the electron transport chain to transfer electrons. B Water, not carbon dioxide, is the source of electrons used in the light-dependent reaction of photosynthesis. C Carbon dioxide is the source of carbon used by green plants to build carbohydrates. D provides a significant source of electrons to the electron transport chain of the light reaction in the absence of light.
A
Which of the following correctly illustrates a dipeptide and an amino acid in the optimal position to form a tripeptide?
A
Which of the following statements best explains the processes of passive and active transport? A Passive transport is the net movement of substances down a concentration gradient that requires metabolic energy. Active transport is the movement of substances up a concentration gradient that does not require energy. B 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. C Passive transport is the net movement of substances up a concentration gradient that requires metabolic energy. Active transport is the movement of substances down a concentration gradient that does not require metabolic energy. D Passive transport is the net movement of substances up a concentration gradient that does not require metabolic energy. Active transport is the movement of substances down a concentration gradient that requires energy.
A
Which of the following statements best justifies the inclusion of test tubes 3 and 7 in the experiment? A They will show whether the isolated cellular contents have enzymatic activity. B They will show whether environmental affects the function of the enzyme. C They will show the rate of product formation in the absence of bacterial factors. D They will show the rate of product formation in the absence of the substrate.
A
A culture of Spirogyra (an autotrophic alga) is maintained in a water solution containing dissolved carbon dioxide and a source of phosphates but lacking nitrogen compounds. 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
A researcher claims that the synthesis of from and inorganic phosphate is essential to cellular function. Which of the following statements best helps justify the researcher's claim? A is a small molecule that some cells release into their environment as a way of communicating with other cells. B hydrolysis is an energy-releasing reaction that is often coupled with reactions that require an input of energy. C Inorganic phosphate is a substance that cells typically acquire from their environment. D synthase is a mitochondrial enzyme that catalyzes the conversion of and to
B
An answer to which of the following questions would provide the most information about the association between the CFTR mutation and the viscous mucus? A Is the mucus also secreted from the cells through the CFTR proteins? B How does the disrupted chloride movement affect the movement of sodium ions and water by the cell? C How does the mutation alter the structure of the CFTR proteins? D What is the change in nucleotide sequence that results in the CFTR mutation?
B
Based on Figure 1, the net number of molecules produced during glycolysis from the metabolism of a single glucose molecule is closest to which of the following? A 0 B 2 C 4 D 8
B
Based on Table 1, which of the following percentages is closest to the solute concentration of the grape? A 0 B 1.3 C 5.5 D 10.1
B
Beaked whales feed at various depths, but they defecate at the ocean's surface. Nitrogen-rich whale feces deposited in surface waters supply nutrients for algae that are eaten by surface dwelling fish. Which of the following best predicts what would happen if the whale population decreased? A There would be a reduction in surface nitrogen concentration, which would cause an algal bloom. B The surface fish populations would decline due to reduced populations of algae. C The remaining whales would accumulate mutations at a faster rate. D The remaining whales would be forced to forage in the deepest parts of the ocean.
B
Cyanobacteria contain a variety of pigment molecules, as shown in Table 1. As a result, the color of cyanobacteria cultures can vary significantly based on the relative amount of each pigment produced. A researcher placed a culture of cyanobacteria under green lights. Within a few weeks, the appearance of the cyanobacteria changed from green to red. The researcher claimed the color change in the culture was the result of an adaptation allowing greater photosynthesis. Which of the following provides the best reasoning to justify the researcher's claim? A In green light, more chlorophyll a molecules are produced, reflecting more light to other cyanobacteria to be used for photosynthesis. B In green light, more phycoerythrin molecules are produced, allowing more green light to be absorbed, thus increasing photosynthesis. C In green light, cyanobacteria that have more phycocyanin molecules are less likely to survive and reproduce. D In green light, cyanobacteria that have more allophycocyanin molecules are more likely to survive and reproduce.
B
In which of the following tubes did the greatest reduction of occur after minutes? A Tube 1 B Tube 2 C Tube 3 D Tube 4
B
The enzyme peroxidase is found in many organisms. It catalyzes the breakdown of hydrogen peroxide into water and oxygen gas. The rate of peroxidase activity at different values was assessed by students in the lab. The students' results are shown in graph 1. If the experiment is repeated at 11, the observed activity level of the enzyme will most likely be A the same as the level at 7 B lower than the level at 9 C greater than the level at 9 D between the levels observed at 5 and 7.
B
The following is a food web for a meadow habitat that occupies 25.6km 2. The primary producers' biomass is uniformly distributed throughout the habitat and totals 1,500 kg/km Developers have approved a project that will permanently reduce the primary producers' biomass by 50 percent and remove all rabbits and deer. Which of the following is the most likely result at the completion of the project? A The biomass of coyotes will be 6 kg, and the biomass of hawks will be 0.5 kg. B The biomass of coyotes will be dramatically reduced. C The coyotes will switch prey preferences and outcompete the hawks. D There will be 50 percent fewer voles and 90 percent fewer hawks.
B
Which of the following graphs is the most appropriate representation of the experimental results documented in the table?
B
Which of the following is responsible for the cohesive property of water? A Hydrogen bonds between the oxygen atoms of two adjacent water molecules B Covalent bonds between the hydrogen atoms of two adjacent water molecules C Hydrogen bonds between the oxygen atom of one water molecule and a hydrogen atom of another water molecule D Covalent bonds between the oxygen atom of one water molecule and a hydrogen atom of another water molecule E Hydrogen bonds between water molecules and other types of molecules
B
Which of the following is the best explanation for the pattern of change in mass of the organisms over time? A Water loss due to evaporation B Cellular respiration C The law of conservation of matter D Growth and reproduction
B
Which of the following is the most likely effect of the mutation at nucleotide position 7 in the GULO gene of humans? A The mutation results in the deletion of the GULO gene, so no polypeptide can be translated. B The deletion of the single nucleotide causes a frame shift, changing the primary structure downstream of the mutation and resulting in a nonfunctional protein. C The point mutation causes a substitution of the amino acid isoleucine (Ile)for histidine (His) at position 7, resulting in a protein with higher than normal activity. D The substitution of a single nucleotide in the GULO coding region results in a stop codon. This results in a smaller nonfunctional protein.
B
Which of the following is the most likely result at the completion of the project? A The biomass of coyotes will be 6 kg, and the biomass of hawks will be 0.5 kg. B The biomass of coyotes will be dramatically reduced. C The coyotes will switch prey preferences and outcompete the hawks. D There will be 50 percent fewer voles and 90 percent fewer hawks.
B
Which of the following statements best describes how organisms such as rabbits obtain the carbon necessary for building biological molecules? A Rabbits eat plants and use energy absorbed from the plants to make carbon atoms from electrons, protons, and neutrons in the air. B Rabbits eat plants and break down plant molecules to obtain carbon and other atoms that they rearrange into new carbon-containing molecules. C Rabbits eat plants and use water absorbed from the plants to hydrolyze , which the rabbits breathe in from the air and use as a carbon source. D Rabbits eat plants and make carbon-containing molecules by using carbon atoms that the plants absorbed from the soil and stored in the cells of their leaves.
B
Which of the following was the dependent variable in the researcher's experiment? A Time B pH C Glucose concentration D Lactic acid concentration
B
Which of the following would be the most appropriate control for this experiment? A A test tube containing no camera film B A test tube containing only a piece of exposed camera film C A test tube containing a piece of exposed camera film submerged in water D A test tube containing a piece of exposed camera film and all three enzyme solutions
B
Which statement best describes the effect on water transport across the cell membrane if the aquaporin in the figure ceases to function? A Water molecules will no longer be able to move across the cell membrane. B Water molecules will still be able to move across the cell membrane but at a slower rate. C Water molecules will only be able to enter the cell by active transport. D Water molecules will move across the cell membrane at a faster rate without the aquaporin regulating their flow.
B
Which statement best helps explain the formation of the hydrogen bond represented in the figure? A The oxygen has a partial positive charge, and the nitrogen has a partial negative charge. B The nitrogen has a partial negative charge, and the hydrogen attached to the oxygen has a partial positive charge. C The hydrogen attached to the oxygen has a partial negative charge, and the nitrogen also has a partial negative charge. D The nitrogen has a partial positive charge, and the hydrogen attached to the oxygen also has a partial positive charge.
B
Yellow-billed cuckoos typically hatch in mid July. Emerging cicadas are a primary food source for nesting cuckoos. Which of the following best predicts the effect of wildfires on yellow-billed cuckoo populations? A The yellow-billed cuckoo population will decline because the decreased ground cover will allow lizards to prey on cuckoo nests. B The yellow-billed cuckoo population will decline because the cicadas will emerge before the hatching season begins. C The yellow-billed cuckoo population will grow because the adults will more easily see and eat the cicada nymphs. D The yellow-billed cuckoo population will remain unchanged because cuckoos do not nest in areas affected by wildfires.
B
A researcher claims that only a portion of the light energy captured by green plants is available for growth and repair. Which of the following observations best helps justify the researcher's claim? A Light-capturing pigment molecules in green plants absorb red, blue, and violet light but reflect green light. B The energy of a photon of light is proportional to its frequency and inversely proportional to its wavelength. C As light energy is converted to chemical energy by metabolic processes, some of the energy is lost as heat. D Captured energy is stored in the molecular bonds of organic molecules, including simple sugars and starch.
C
Based on the data in the table, which of the following best explains the effects of rotenone on cellular respiration? A Rotenone acts as an inhibitor of the enzymes in the Krebs cycle. B , produced during glycolysis, is not able to enter the mitochondria because transport proteins are blocked from entering. C Treated cells are not able to break down because certain enzymes of the electron transport chain are inhibited. D Rotenone acts as an allosteric inhibitor of glycolytic enzymes, thus inhibiting cellular respiration.
C
Figure 1 shows a model of how a channel protein influences the movement of a particle across a cell's plasma membrane. Figure 1. A section of a cell's plasma membrane, showing a channel protein and a concentration gradient across the membrane 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? A Add small nonpolar molecules to the extracellular space and measure the direction of particle movement of the molecules. B Measure the rate of extracellular fluid movement into the intracellular space. C Add more of the proteins to the plasma membrane and measure the rate of the particle movement. D Remove from the intracellular space and measure the rate of the particle movement into the intracellular space.
C
If of the nucleotides in a single-stranded molecule are adenine, then what percent are expected to be thymine? A 0% B 20% C 30% D 70%
C
If ATP breakdown (hydrolysis) is inhibited, which of the following types of movement across cell membranes is also inhibited? A Movement of oxygen into a cell B Movement of water through aquaporins C Passage of a solute against its concentration gradient D Facilitated diffusion of a permeable substance
C
In an experiment, cells were isolated from an aquatic plant and suspended in pond water, a sucrose sugar solution, or distilled water. All of the cells were then viewed under a microscope. Compared with the cell in the pond water, the cell in the sugar solution appeared shriveled, and the cell in the distilled water appeared inflated. The results of the experiment are represented in Figure 1.Which of the following statements best explains the observations represented in Figure 1 ? A There was a net movement of sucrose out of the cell suspended in the sugar solution and a net movement of sucrose into the cell suspended in the distilled water. B There was a net movement of sucrose into the cell suspended in the sugar solution and a net movement of sucrose out of the cell suspended in the distilled water. C 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. D There was a net movement of water into the cell suspended in the sugar solution and a net movement of water out of the cell suspended in the distilled water.
C
In the American Southwest, annually emerging cicadas are dependent upon the cottonwood trees in the floodplain. Adult male cicadas perch in the cottonwood trees and chirp to attract females. Females lay their eggs in the branches of the cottonwoods, and, upon hatching, the cicada nymphs drop to the ground, burrow into the soil, feed on the tree roots, and later emerge as adults. Other organisms in the floodplain community prey on the cicadas, as shown in the food web. Human activity has caused a decrease in the amount of flooding and an increase in the incidence of wildfires in the floodplain. In an investigation into the recent changes in the floodplain ecosystem, researchers monitored the soil temperature, amount of cottonwood ground coverage (i.e., area of the ground that is shaded by leaves), and cicada. The results of the investigation are represented in Figure 2 and Figure 3. Which of the following statements best predicts the effect of increased cottonwood growth on the food web? A Increased cottonwood growth will lead to an increase in the number of primary consumers, resulting in more competition between kestrels and sparrows for food. B Increased cottonwood growth will decrease the habitat available for lizards, resulting in a decline in the number of kestrels. C Increased cottonwood growth will provide more resources for cicadas, resulting in an increase in the kestrel population. D Increased cottonwood growth will lead to a large accumulation of dead wood that serves as fuel for wildfires, resulting in the collapse of the food web.
C
In the Arctic Ocean, the predominant primary producers are phytoplankton. Phytoplankton are consumed by zooplankton, which in turn are eaten by codfish. In years when there is more open water (less ice coverage), there are more zooplankton and fish than in years with less open water (more ice coverage). Based on the graph above, the difference is most likely because A when there is less open water, light is blocked from the zooplankton, so they cannot produce as much food for the fish B when there is more open water, the temperature is warmer, so the zooplankton and fish populations increase in size C the ice blocks the light, so in years with more ice coverage, there is less photosynthesis by the phytoplankton D the ice increases the light available for photosynthesis, so primary production increases and zooplankton populations increase in size
C
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? A The two processes will occur simultaneously in prokaryotes but not eukaryotes. B Prokaryotic mRNA is shorter than eukaryotic mRNA C Eukaryotic mRNA contains more coding regions than prokaryotic DNA D The processing of mRNA by eukaryotes is required for the to leave the nucleus.
C
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. Figure 1. A model showing a cell engulfing a smaller cell Which of the following provides evidence to best support the researchers' claim? A The organelle has a phospholipid membrane. B The organelle has protein in the membrane. C The organelle has a double membrane. D The organelle has an internal aqueous environment that is similar to the cytosol of the larger cell.
C
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? A Insertion B Deletion C Substitution D Frameshift
C
Site of modification and packaging of proteins and lipids prior to export from the cell A A B B C C D D E E
C
The diagram above represents a typical rod-shaped bacterium. Which of the following best describes a feature shown in the diagram that is unique to archaea and bacteria? A The organism is surrounded by a cell wall. B The organism contains ribosomes. C The organism does not have a nuclear membrane surrounding its genetic material. D The organism is not capable of making or providing itself with ATP.
C
The results of the experiment can be used as evidence in support of which of the following scientific claims about mitochondrial activity? A Mitochondria in a cell-free environment are unable to convert thermal energy into ATP. B The electron transport chain pumps electrons from the cytosol to the mitochondrial matrix. C ATP production in mitochondria requires a hydrogen ion gradient that favors movement of protons into the mitochondrial matrix. D ATP synthase molecules change their orientation in relation to the proton gradient across the mitochondrial membrane.
C
Which of the following best describes the hydrolysis of carbohydrates? A The removal of a water molecule breaks a covalent bond between sugar monomers. B The removal of a water molecule forms a covalent bond between sugar monomers. C The addition of a water molecule breaks a covalent bond between sugar monomers. D The addition of a water molecule forms a covalent bond between sugar monomers.
C
Which of the following describes the relationship between the amount of chlorophyll a in a water sample and the concentration of nitrogen in that sample?A As the concentration of chlorophyll a increases, the concentration of nitrogen decreases. B The concentrations of nitrogen and chlorophyll a are directly correlated. C The concentrations of chlorophyll a and nitrogen increase throughout the year. D There is no relationship between the concentrations of chlorophyll a and nitrogen.
C
Which of the following observations provides the best evidence that photosynthesis occurred in treatment group ? A The specimens in the beakers were aquatic plants from a large aquarium. B The beakers were placed in the light. C The mean of the samples increased after one hour. D The standard error of the mean was smaller than that for treatment group .
C
Which of the following scientific questions is most relevant to the model represented in the figure above? A Is required for the transportation of sugars across the outer mitochondrial membrane? B Do the types of phospholipids in a membrane affect the rate at which molecules enter a cell by passive diffusion? C Which molecular substance is actively transported across the plasma membrane? D How does temperature affect the movement of molecules into lysosomes?
C
Which of the following statements about glucose, galactose, and fructose is most likely true? A The carbohydrates have the same properties because they have the same number of carbon, hydrogen, and oxygen atoms. B The carbohydrates have the same properties because they each have a single carbon-oxygen double bond. C The carbohydrates have different properties because they have different arrangements of carbon, hydrogen, and oxygen atoms. D The carbohydrates have different properties because they have different numbers of carbon-carbon bonds.
C
Which of the following statements best describes how molecules released by the fish become nutrients for the plants? A The carbon dioxide molecules released by the fish are converted by the bacteria to oxygen atoms, which are used by the plants to make water molecules. B The oxygen molecules released by the fish are converted by the bacteria to ammonia molecules, which are used by the plants to make lipids and fatty acids. C The nitrites released by the fish are converted by the bacteria to carbon dioxide molecules, which are used by the plants to make carbohydrates. D 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.
C
Which of the following statements best justifies the inclusion of test tube as a control in the experiment? A It will provide a measurement of amylase activity at an acidic . B It will provide a measurement of amylase activity at a basic . C It will show the color change that occurs in the absence of enzyme activity. D It will show the color change that occurs in the absence of the amylase protein.
C
Which two cellular organelles in eukaryotes have both electron transport systems and chemiosmotic mechanisms? A Ribosomes and endoplasmic reticulum B Chloroplasts and endoplasmic reticulum C Chloroplasts and mitochondria D Mitochondria and nuclei E Nuclei and Golgi apparatus
C
A researcher claims that increased atmospheric carbon dioxide levels cause increased growth rates in plants. Which of the following statements best supports the researcher's claim?A Atmospheric carbon dioxide is produced by the burning of fossil fuels, which are formed from the remains of living organisms such as plants. B Atmospheric carbon dioxide is a byproduct of cellular respiration, which is a metabolic process that occurs in plants and other living organisms. C Atmospheric carbon dioxide typically enters plant leaves through stomata, which plants rely on for regulating gas exchange with the atmosphere. D Atmospheric carbon dioxide is the raw material for photosynthesis, which plants rely on for producing sugars and other organic compounds.
D
A sample of human blood was placed in a test tube containing a physiological saline solution (0.9% sodium chloride). This type of solution is often used intravenously to quickly rehydrate patients. A drop of the blood from the test tube was placed on a slide and red blood cells (RBCs) were observed under a microscope. Three possible outcomes are diagrammed below. Which of the following best predicts which diagrammed microscope view the laboratory worker would see and best explains why? A View 1 because RBC membranes are freely permeable to water B View 2 because the RBCs use energy to allow sodium entry and to pump water out C View 2 because the rate of water movement into the RBCs equals the rate of water movement out of the cells D View 3 because the sodium-potassium pumps in the RBC membranes use energy to keep the sodium out but allow water to freely flow into the cells
D
Alcohol dehydrogenase ( ) is an enzyme that aids in the decomposition of ethyl alcohol into nontoxic substances. Methyl alcohol acts as a competitive inhibitor of ethyl alcohol by competing for the same active site on . When attached to , 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? A There will be an increase in formaldehyde because activity increases. B Competitive inhibition will be terminated because ethyl alcohol will bind to methyl alcohol and decrease activity. C The peptide bonds in the active site of the enzyme will be denatured, inhibiting the enzyme. D Competitive inhibition will decrease because the proportion of the active sites occupied by substrate will increase.
D
Assume there are 50,000 joules (J) of energy available in trophic level II in the figure. According to the conventional model of energy flow in ecosystems, which of the following statements correctly describes the flow of energy in the system? A Trophic level I generates a maximum of 50,000 J of energy. B Trophic level I has approximately 5,000 J of available energy. C Trophic level III has approximately 50 J of available energy. D Trophic level IV has approximately 500 J of available energy.
D
Changing the shape or morphology of the mitochondrial inner membrane can change the efficiency of mitochondrial function. Which of the following outcomes will most likely result from a change in the shape of the mitochondrial inner membrane from a highly folded surface to a smooth, flat surface? A Mitochondria will become more efficient because the inner mitochondrial membrane will become more permeable to ions. B Mitochondria will become more efficient because the total volume of the mitochondria will increase. C Mitochondria will become less efficient because the inner mitochondrial membrane will become less permeable to large molecules. D Mitochondria will become less efficient because the surface area of the inner mitochondrial membranes will decrease.
D
Figure 1 shows the amount of product produced in an enzyme-catalyzed reaction over five minutes. Which of the following best explains how the rate of the reaction changes over time? A The rate increases because more products are made over time. B The rate increases because the ratio of product to substrate increases. C The rate decreases because the ratio of product to substrate increases. D The rate decreases because the enzyme is used up as the reaction progresses.
D
Given the codon chart listed below, what would be the effect of a mutation that deletes the G at the beginning of the DNA sequence?A The mutation precedes the gene, so no changes would occur. B Lysine (lys) would replace glutamine (gln), but there would be no other changes. C The first amino acid would be missing, but there would be no other change to the protein. D The reading frame of the sequence would shift, causing a change in the amino acid sequence after that point.
D
If is added to cells undergoing cellular respiration, which of the following will most likely accumulate in the cells? A Glucose Transporter B Pyruvate C Phosphoenolpyruvate ( ) D 2 phosphoglycerate
D
Members of which species are herbivores? A A B B C C D D E E
D
Of the following, which additional investigation can be used to determine when the cells are in an isotonic solution? A Decreasing the salinity of the environment a little at a time until the usage reaches a maximum B Decreasing the salinity of the environment a little at a time until usage reaches a minimum C Increasing the salinity of the environment a little at a time until usage reaches a maximum D Increasing the salinity of the environment a little at a time until the usage reaches a minimum
D
Pyruvate dehydrogenase deficiency is a genetic disease most commonly linked to a mutation in the - subunit of the mitochondrial enzyme that causes the enzyme to cease functioning. As a result of the mutation, affected individuals build up dangerous amounts of lactic acid. Which of the following best explains the buildup of lactic acid in individuals with the mutation? A Cells use lactic acid to shunt electrons from pyruvate to the electron transport chain in the mitochondria. B Cells undergo glycolysis because there is a buildup of pyruvate in affected individuals. C Cells cannot transport pyruvate to the mitochondria in the absence of pyruvate dehydrogenase activity, so the pyruvate is broken down to lactic acid and ethanol. D Cells undergo fermentation because pyruvate cannot be metabolized to proceed into the Krebs cycle.
D
Pyruvate dehydrogenase is an enzyme that converts pyruvate to acetyl- . Acetyl- is further metabolized in the Krebs cycle. A researcher measured the accumulation of acetyl- in a reaction containing pyruvate and pyruvate dehydrogenase under several different conditions (Figure 1). Which of the following best describes the cellular location where pyruvate dehydrogenase is most likely active? A The cytosol B The lysosomes C The nucleus D The mitochondrial matrix
D
The hydrolytic enzymes are most likely to accumulate in which of the following cellular structures? A Nucleus B Mitochondrion C Smooth endoplasmic reticulum D Golgi complex
D
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? A Glucose is transported into the cell by active transport. B Na+ is transported into the cell by active transport. C The movement of glucose through the membrane requires ATP hydrolysis. D Na+ transport out of the cell requires ATP hydrolysis.
D
The protein is made up of amino acids linked together in a chain. Some humans produce a version of the protein in which phenylalanine (an amino acid) has been deleted from position 508 of the amino acid chain. Which of the following best predicts how the amino acid deletion will affect the structure of the protein? A It will have no observable effect on the structure of the protein. B It will affect the primary structure of the protein, but the other levels of protein structure will not be affected. C It will affect the secondary and tertiary structures of the protein, but the primary structure will not be affected. D It will affect the primary, secondary, and tertiary structures of the protein.
D
The results for treatment groups and could suggest which of the following questions about the design of the experiment? A Do the glass beakers prevent light from reaching the test samples? B Is the method used for measuring harmful to aquatic organisms? C Is the availability of carbon dioxide a limiting factor in aquatic ecosystems? D Does the aquarium water contain living microorganisms?
D
Which of the following best describes an event during step 2 in the simplified model above? A A new RNA molecule is synthesized using a DNA template. B A new polypeptide is synthesized using an RNA template. C Thymine nucleotides in an RNA molecule are replaced with uracil nucleotides. D Noncoding sequences are removed from a newly synthesized RNA molecule.
D
Which of the following best explains how affected the reaction? A acts as a second buffer in the reaction. B acts as an additional carrier of electrons from photosystem to . C acts as an additional source of electrons to the light reaction of photosynthesis. D acts as an inhibitor to the movement of electrons within the light reaction of photosynthesis.
D
Which of the following groups of cellular components are found in eukaryotic cells but not prokaryotic cells? A Ribosomes, a nucleus, and chloroplasts B Circular chromosomes, mitochondria, and an endoplasmic reticulum C A nucleus, ribosomes, and cell walls D An endoplasmic reticulum, mitochondria, and a nucleus
D
Which of the following is an accurate description of the process shown in Figure 1 ? A The linking of amino acids with an ionic bond as an initial step in the protein synthesis process B The formation of a more complex carbohydrate with the covalent bonding of two simple sugars C The hydrolysis of amino acids with the breaking of covalent bonds with the release of water D The formation of a covalent peptide bond in a dehydration synthesis reaction
D
Which of the following statements about the rate of fixation in the two types of plants is supported by the data shown in the figures? A At , plant type has a lower rate of fixation than plant type does in both types of soil. B At , plant type has a higher rate of fixation than plant type does in the dry soil but not in the control soil. C Plant types and have a statistically different rate of fixation in both soil types at both oxygen levels. D The rate of fixation is the same in both types of plants in the control soil at both oxygen levels.
D
he diagram shows how water can adhere to the xylem in the stems of plants, which contributes to water movement in the plant. Which of the following best explains how water is able to move upward from the roots of a plant, through its xylem in the stem, and out to the leaves? A Water is polar, and the walls of the xylem are nonpolar. Water molecules have the ability to form hydrogen bonds with one another but not with the xylem walls. B Water is nonpolar, and the walls of the xylem are polar. Water molecules are able to form hydrogen bonds with the xylem walls, and they are pulled up the xylem. C Water and the xylem are both nonpolar. Water molecules have the ability to form hydrogen bonds with one another but not with the xylem walls. D Water and the xylem are both polar. Water molecules have the ability to form hydrogen bonds with each other and with the walls of the xylem.
D
If a segment of DNA is 5'-TAC GAT TAG-3', the RNA that results from the transcription of this segment will be A 3'-TAC GAT TAU-5' B 3'-ATG CTA ATA-5' C 3'-UAC GAU UAG-5' D 3'-AAC GAU UAA-5' E 3'-AUG CUA AUC-5'
E
If the potato solution was boiled for 10 minutes and cooled for 10 minutes before being tested, the average time for the disks to float to the surface of the hydrogen peroxide solution would be A less than 1 second B 5 seconds C 10 seconds D 30 seconds E more than 30 seconds
E
Site of glucose synthesis A A B B C C D D E E
E
Which of the following best describes the function of the coenzymes NAD + and FAD in eukaryotic cellular respiration? A They participate in hydrolysis reactions by accepting protons from water molecules. B They participate directly in the phosphorylation of ADP to ATP. C They serve as final electron acceptors in the electron transport chain. D They aid vitamins such as niacin in the breakdown of glucose. E They accept electrons during oxidation-reduction reactions.
E
Which of the following conclusions is best supported by the data?A Nongerminating pea seeds have a higher rate of respiration than germinating pea seeds do. B Light is required for pea seed germination. C In the nongerminating pea seeds, oxygen consumption is directly proportional to oxygen concentration. D Less carbon dioxide is produced by germinating pea seeds at 26ºC than at 10ºC. E In pea seeds an increase in temperature results in an increase in oxygen consumption.
E
