AP Biology Practice Test 35

Test Information

Question 14 questions

Time 16 minutes

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1. Amino acids are joined together by peptide bonds to form proteins. Which of the following groups of amino acid molecules is arranged so that the circled atoms will properly form a peptide bond?

Questions 2-3 refer to the following information.

Questions refer to the following figure of the glycophorin A protein, a protein passing through the plasma membrane, extending from the cytosol to the extracellular fluid. The protein consists of two identical polypeptides, each forming a helix within the membrane. Circles represent amino acids and squares represent carbohydrate side groups.

2. The parts of the protein represented by the shaded circles (numbers 73–95) are most likely dominated by amino acids with

3. The protein shown in the figure illustrates characteristics of which levels of protein structure?

Questions 4-9 refer to the following information.

A student experiment investigates the effects that the presence and absence of light have on the metabolic activities of the aquatic plant Elodea. Bromothymol blue (BTB), a pH indicator that changes from yellow to blue as the pH of the solution changes, is used to identify changes in pH that result from the metabolic activities of Elodea. Seven test tubes are prepared, as follows:

Reaction I: BTB + CO2

Reaction II: BTB + no light

Reaction III: BTB + CO2 + light

Reaction IV: BTB + CO2 + Elodea + light

Reaction V: BTB + Elodea + light

Reaction VI: BTB + Elodea + no light

Reaction VII: BTB + CO2 + Elodea + no light

The following reactions and figure may be useful for interpreting the results of the experiment:

4. The addition of carbon dioxide (CO2) to BTB has which of the following effects?

5. In Reaction IV, the BTB solution with Elodea changes from yellow to blue when exposed to light. Which of the following is the most likely cause of this change?

6. Which reaction supports a conclusion that the change in the color observed in Reaction IV is caused by the influence of light on Elodea and not by some acidic or basic substance in the Elodea plant?

7. What metabolic process is responsible for the change observed in Reaction VI?

8. Which of the following reactions is a control for Reaction VI?

9. Which of the following can be used to demonstrate that a metabolic activity rather than a substance stored in the Elodea plant is responsible for the change observed in Reaction VI?

10. The following map shows the distribution of the B allele across Europe and Africa.

Which of the following best explains the distribution of the B allele across Europe and Africa?

11. The following table describes the distribution of O, A, B, and AB blood types among four populations of Native Americans.



Phenotypic Percentages
NavahosNorthern Mexico78220.00.0

Historically, the Blackfeet of Montana were a small, isolated population. Which of the following best explains their distinctive phenotypic percentages as compared to the other three Native American populations?

Questions 12-14 refer to the following information.

Oxygen is transported throughout the body by hemoglobin molecules within red blood cells. The blood types A, B, and O identify red blood cells distinguished by specific sugars attached to membrane-bound proteins. There are three alleles (A, B, and O), two of which (A and B) code for enzymes that attach a specific sugar to the membrane-bound protein. The combination of any two of the three alleles results in six genotypes, producing four phenotypes, A, B, AB, and O.

The following figure of a phylogenetic tree shows the nucleotide substitutions, deletions, and insertions for one possible explanation for the evolution of the ABO allele group.

12. According to the phylogenetic tree, which of the alleles is the most likely ancestral?

13. If the exon of the A allele contains 1065 nucleotides, how many nucleotides code for the B allele?

14. Unlike the A and B alleles, the enzyme produced by the O allele does not attach any sugars to the membrane-bound protein. Considering the phylogenetic tree above, which of the following provides the best explanation for why this might be?