AP Biology Practice Test 39

Test Information

Question 13 questions

Time 16 minutes

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1. The reaction A + B → C is catalyzed by enzyme K. If the reaction is in equilibrium, which of the following would allow more product C to be produced?

2. Which of the following would most likely provide examples of mitotic cell divisions?

3. Most animal cells, regardless of species, are relatively small and about the same size. Relative to larger cells, why is this?

Questions 4-6 refer to the following information.

Questions refer to the following figure that illustrates the evolution of nine species from a single ancestral species. Roman numerals I through V identify different areas of the figure.

4. During which of the indicated periods is the rate of evolution most rapid?

5. Which of the following could be responsible for the evolutionary pattern indicated by area III?

6. If the diagram describes the pattern of evolution after a single species is introduced to a remote, newly formed island, the pattern in the diagram best suggests

Questions 7-8 refer to the following information.

A clear plastic chamber containing a cylindrical cage was used as an animal chamber. An opening at one end of the chamber was sealed with a stopper. Passing through the stopper was a graduated burrette. Gas production or consumption inside the chamber could be measured by movements of a solution rising or falling inside the burrette. Potassium hydroxide (KOH) was added to the chamber to absorb any CO2 produced.

Twenty hamsters were weighed and put into one of 20 chambers. Half of the chambers were maintained at 10°C, and half were maintained at 25°C. Oxygen consumption in ml was recorded for each hamster every 30 seconds and plotted as ml per gram of hamster weight. The data are shown in the graph that follows.

7. The data in the graph above are consistent with which of the following conclusions?

8. All of the following must remain unchanged during data collection EXCEPT:

9. Question below refers to the following ecological pyramid.

If the figure illustrates a pyramid of numbers, which of the following would best explain the relative sizes of the trophic levels?

10. Which of the changes below following the start codon in an mRNA would most likely have the greatest deleterious effect?

11. All of the following support the endosymbiotic theory that ancestors of mitochondria and chloroplasts were once independent, free-living prokaryotes EXCEPT:

Questions 12-13 refer to the following information.

Mitochondria isolated from cells can be induced to carry out respiration if an appropriate substrate is provided and a low temperature is maintained to prevent enzyme degradation. The following experiment uses isolated mitochondria in this manner to investigate respiration.

During the Krebs cycle, succinate is oxidized to fumarate as electrons are transferred to FAD for its reduction to FADH2 (see figure above). In this experiment, DPIP is provided as a substitute electron acceptor for FAD. DPIP, which is blue in its oxidized state, accepts electrons from succinate. After accepting the electrons, DPIP turns clear, its reduced state. A spectrophotometer is used to quantify the degree of color change by measuring the amount of light that is transmitted through a cuvette. A cuvette with a higher transmittance percentage indicates a solution with more reduced DPIP.

Three cuvettes are prepared at low temperatures with an appropriate buffer. The contents of a fourth cuvette is similarly prepared except that the mitochondrial suspension is first preheated to 100°C and then returned to a low temperature. Distilled water was added to bring the contents of all cuvettes to the same volume. A summary of the contents of the cuvettes follows:

Cuvette 1: 0.2 ml succinate added to isolated mitochondria

Cuvette 2: 0.1 ml succinate added to isolated mitochondria

Cuvette 3: 0 ml succinate added to isolated mitochondria

Cuvette 4: 0.1 ml succinate added to isolated mitochondria preheated to 100°C

Transmittance in each cuvette is measured every 10 minutes. The results of the experiment are summarized in the following graph.

12. The results of the experiment indicate that the respiratory rate increases as

13. Which of the following is true with respect to the availability of electrons from other steps of the Krebs cycle?