BIOLOGY

Which of the following plates would have the highest percentage of bacteria that are expected to produce insulin? (A) I only (B) III only (C) IV only (D I and III

C

13. According to the results of this experiment, germination of tobacco seeds during the first week is (A) increased by exposure to light (B) unaffected by light intensity (C) prevented by paper towels (D) accelerated in green-leaved seedlings

A

20. 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 (A) properties of the molecule as a result of abnormal interactions between adjacent hemoglobin molecules (B) DNA structure as a result of abnormal hydrogen bonding between nitrogenous bases (C) fatty acid structure as a result of changes in ionic interactions between adjacent fatty acid chains (D) protein secondary structure as a result of abnormal hydrophobic interactions between R-groups in the backbone of the protein

A

Based on the diagram, which of the following best explains why the oak trees are later replaced by other trees?

A

Based on your understanding of the ways in which signal transmission mediates cell function, which of the following predictions is most consistent with the information given above? (A) In an environment with low fixed nitrogen, treating the Anabaena cells with a calcium-binding compound should prevent heterocyst differentiation. (B) A strain that overexpresses the patS gene should develop many more heterocysts in a low fixed nitrogen environment. (C) In an environment with abundant fixed nitrogen, free calcium levels should be high in all cells so that no heterocysts develop. (D) In environments with abundant fixed nitrogen, loss of the hetR gene should induce heterocyst development.

A

Plates I and III were included in the experimental design in order to (A) demonstrate that the E. coli cultures were viable (B) demonstrate that the plasmid can lose its ampr gene (C) demonstrate that the plasmid is needed for E. coli growth (D) prepare the E. coli for transformation

A

Strenuous exercise lowers the blood pH, causing the curves for both hemoglobin and myoglobin to shift to the right. This shift results in (A) an unloading of O2 at higher partial pressures (B) an increase in the number of O2-binding sites (C) the capture of more O2 by hemoglobin (D) the capture of more O2 by myoglobin

A

Which of the following best explains why there is no growth on plate II? (A) The initial E. coli culture was not ampicillin-resistant. (B) The transformation procedure killed the bacteria. (C) Nutrient agar inhibits E. coli growth. (D) The bacteria on the plate were transformed.

A

Which of the following conclusions is best supported by the data? (A) Bicoid protein inhibits translation of caudal mRNA. (B) Bicoid protein stabilizes caudal mRNA. (C) Translation of bicoid mRNA produces caudal protein. (D) Caudal protein stimulates development of anterior structures.

A

Which of the following graphs properly represents the humoral immune response when an individual is exposed to the same antigen more than once?

A

Which of the following is the most plausible explanation for these findings? (A) A cell surface protein on cell 4 signals cell 3 to induce formation of the worm's intestine. (B) The plasma membrane of cell 4 interacts with the plasma membrane of the posterior portion of cell 3, causing invaginations that become microvilli. (C) Cell 3 passes an electrical signal to cell 4, which induces differentiation in cell 4. (D) Cell 4 transfers genetic material to cell 3, which directs the development of intestinal cells.

A

27. Which of the following statements best explains why there are fewer colonies on plate IV than on plate III? (A) Plate IV is the positive control. (B) Not all E. coli cells are successfully transformed. (C) The bacteria on plate III did not mutate. (D) The plasmid inhibits E. coli growth.

B

29. Experimental evidence shows that the process of glycolysis is present and virtually identical in organisms from all three domains, Archaea, Bacteria, and Eukarya. Which of the following hypotheses could be best supported by this evidence? (A) All organisms carry out glycolysis in mitochondria. (B) Glycolysis is a universal energy-releasing process and therefore suggests a common ancestor for all forms of life. (C) Across the three domains, all organisms depend solely on the process of anaerobic respiration for ATP production. (D) The presence of glycolysis as an energy-releasing process in all organisms suggests that convergent evolution occurred.

B

Based on the chart, which of the following would be the most reasonable plan for the students to follow? (A) Searching horizontal rock layers in any class of rock and trying to find those that contain the greatest number of fossils (B) Collecting fossils from rock layers deposited prior to the Permian period that contain some early vertebrate bones (C) Looking in sedimentary layers next to bodies of water in order to find marine fossils of bivalves and trilobites (D) Using relative dating techniques to determine the geological ages of the fossils found so they can calculate the rate of speciation of early organisms

B

The data in the graph best support which of the following claims? (A) Environmental contamination elevates total testosterone oxido-reductase activity in females. (B) Environmental contamination reduces total testosterone oxido-reductase activity in females. (C) Environmental contamination elevates total testosterone oxido-reductase activity in males. (D) Environmental contamination reduces total testosterone oxido-reductase activity in males.

B

The most probable cause for the difference in mean stem length between plants in dish A and plants in dish B is which of the following? (A) Shortening of cells in the stem in response to the lack of light (B) Elongation of seedlings in response to the lack of light (C) Enhancement of stem elongation by light (D) Genetic differences between the seeds

B

Which of the following demonstrates negative feedback by the endocrine system? (A) During labor, the fetus exerts pressure on the uterine wall, inducing the production of oxytocin, which stimulates uterine wall contraction. The contractions cause the fetus to further push on the wall, increasing the production of oxytocin. (B) After a meal, blood glucose levels become elevated, stimulating beta cells of the pancreas to release insulin into the blood. Excess glucose is then converted to glycogen in the liver, reducing blood glucose levels. (C) At high elevation, atmospheric oxygen is more scarce. In response to signals that oxygen is low, the brain decreases an individual's rate of respiration to compensate for the difference. (D) A transcription factor binds to the regulatory region of a gene, blocking the binding of another transcription factor required for expression.

B

Which of the following is the correct explanation for the data? (A) At higher osmolarity, lower rates of contraction are required because more salt diffuses into the paramecia. (B) The contraction rate increases as the osmolarity decreases because the amount of water entering the paramecia by osmosis increases. (C) The contractile vacuole is less efficient in solutions of high osmolarity because of the reduced amount of ATP produced from cellular respiration. (D) In an isosmotic salt solution, there is no diffusion of water into or out of the paramecia, so the contraction rate is zero.

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

f the input water is labeled with a radioactive isotope of oxygen, 18O, then the oxygen gas released as the reaction proceeds is also labeled with 18O. Which of the following is the most likely explanation? (A) During the light reactions of photosynthesis, water is split, the hydrogen atoms combine with the CO2, and oxygen gas is released. (B) During the light reactions of photosynthesis, water is split, removing electrons and protons, and oxygen gas is released. (C) During the Calvin cycle, water is split, regenerating NADPH from NADP+, and oxygen gas is released. (D) During the Calvin cycle, water is split, the hydrogen atoms are added to intermediates of sugar synthesis, and oxygen gas is released.

B

10. According to the data, the crickets at 25°C have greater oxygen consumption per gram of tissue than do the crickets at 10°C. This trend in oxygen consumption is the opposite of that in the mice. The difference in trends in oxygen consumption among crickets and mice is due to their (A) relative size (B) mode of nutrition (C) mode of internal temperature regulation (D) mode of ATP production

C

11. Which of the following statements most directly supports the claim that different species of organisms use different metabolic strategies to meet their energy requirements for growth, reproduction, and homeostasis? (A) During cold periods pond-dwelling animals can increase the number of unsaturated fatty acids in their cell membranes while some plants make antifreeze proteins to prevent ice crystal formation in tissues. (B) Bacteria lack introns while many eukaryotic genes contain many of these intervening sequences. (C) Carnivores have more teeth that are specialized for ripping food while herbivores have more teeth that are specialized for grinding food. (D) Plants generally use starch molecules for storage while animals use glycogen and fats for storage.

C

16. Additional observations were made on day 21, and no yellow-leaved seedlings were found alive in either dish. This is most likely because (A) yellow-leaved seedlings were unable to absorb water from the paper towels (B) taller green-leaved seedlings blocked the light and prevented photosynthesis (C) yellow-leaved seedlings were unable to convert light energy to chemical energy (D) a higher rate of respiration in yellow-leaved seedlings depleted their stored nutrients

C

33. Which of the following statements is correct? (A) At 10 mm Hg partial pressure, hemoglobin binds oxygen but myoglobin does not. (B) At 20 mm Hg partial pressure, myoglobin and hemoglobin bind oxygen in equal amounts. (C) At 40 mm Hg partial pressure, myoglobin has a greater affinity for oxygen than hemoglobin has. (D) At 80 mm Hg partial pressure, myoglobin binds twice as much oxygen as hemoglobin binds.

C

Plates that have only ampicillin-resistant bacteria growing include which of the following? (A) I only (B) III only (C) IV only (D) I and II

C

The results of Miller's experiments best support which of the following hypotheses? (A) The molecules essential to life today did not exist at the time Earth was first formed. (B) The molecules essential to life today could not have been carried to the primordial Earth by a comet or meteorite. (C) The molecules essential to life today could have formed under early Earth conditions. (D) The molecules essential to life today were initially self- replicating proteins that were synthesized approximately four billion years ago.

C

Which of the following is the best prediction of the algal growth if nitrate is added instead of phosphate?

C

Which of the following phylogenetic trees is most consistent with the data

C

If ADH secretion is inhibited, which of the following would initially result? (A) The number of aquaporins would increase in response to the inhibition of ADH. (B) The person would decrease oral water intake to compensate for the inhibition of ADH. (C) Blood filtration would increase to compensate for the lack of aquaporins. (D) The person would produce greater amounts of dilute urine.

D

Which of the following best describes the physiological significance of the different oxygen-binding capabilities of hemoglobin and myoglobin? (A) They prevent muscles from depleting oxygen levels in the blood. (B) They cause muscles to become anaerobic. (C) They prevent glycogen depletion in muscles. (D) They enhance movement of oxygen from the blood into the muscles.

D

Which of the following best supports the hypothesis that the difference in leaf color is genetically controlled? (A) The number of yellow-leaved seedlings in dish A on day 7 (B) The number of germinated seeds in dish A on days 7 and 14 (C) The death of all the yellow-leaved seedlings (D) The existence of yellow-leaved seedlings as well as green-leaved ones on day 14 in dish B

D

Which of the following explains how genetic variation in a population of bacteria results from this process? (A) Bacterial proteins transferred from the donor bacterium by the phage to the recipient bacterium recombine with genes on the recipient's chromosome. (B) The recipient bacterium incorporates the transduced genetic material coding for phage proteins into its chromosome and synthesizes the corresponding proteins. (C) The phage infection of the recipient bacterium and the introduction of DNA carried by the phage cause increased random point mutations of the bacterial chromosome. (D) DNA of the recipient bacterial chromosome undergoes recombination with DNA introduced by the phage from the donor bacterium, leading to a change in the recipient's genotype.

D

Which of the following figures correctly depicts the interactions at the lac operon when lactose is NOT being utilized?

D

Which of the following includes the most likely change in the coloration of the beetle population after pollution and a correct rationale for the change? (A) The coloration range shifted toward more light-colored beetles, as in diagram I. The pollution helped the predators find the darkened tree trunks. (B) The coloration in the population split into two extremes, as in diagram II. Both the lighter-colored and the darker-colored beetles were able to hide on the darker tree trunks. (C) The coloration range became narrower, as in diagram III. The predators selected beetles at the color extremes. (D) The coloration in the population shifted toward more darker- colored beetles, as in diagram IV. The lighter-colored beetles were found more easily by the predators than were the darker- colored beetles.

D

Which of the following statements best explains the data? (A) The appearance of blue in the F1 generation of the pink and white cross demonstrates that flower color is not an inherited trait but is determined by the environment. (B) Flower color depends on stages of flower development, and young flowers are white, advancing to pink and then blue. (C) Since the F1 and F2 phenotypes of the pink and white cross do not fit the expected genotypic and phenotypic ratios, blue-eyed Mary must reproduce by vegetative propagation. (D) Flower color is an inherited trait, and the F1 and F2 phenotypes of the flowers arising from the pink and white cross can best be explained by another gene product that influences the phenotypic expression

D