AP Biology Practice Test 12

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Question 12 questions

Time 15 minutes

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1. Here is a graph showing the rate of photosynthesis of a green plant plotted against light intensity.

Which of the following statements accurately accounts for the shape of the graph?

2. The lac operon is found only in prokaryotes and consists of structural genes and a promoter and operator. Which of the following statements explains why we study the lac operon?

3. Here is the simplified equation for photosynthesis:

6CO2 + 12 H2O → C6H12O6 + 6H2O + 6O2

Which of the following choices correctly traces the atom identified with an arrow?

4. The plasma membrane is selectively permeable and regulates what enters and leaves a cell. It consists of a phospholipid bilayer embedded with proteins. Which of the following statements about the membrane is correct?

5. Active transport involves the movement of a substance across a membrane against its concentration or electrochemical gradient. Active transport is mediated by specific transport proteins and requires the expenditure of energy. Which of the following statements describes an example of active transport?

6. Here is a sketch of an animal cell.

Which of the following statements is correct?

7. Chronically high levels of glucocorticoids can result in obesity, muscle weakness, and depression. This looks like several diseases but actually is only one, Cushing syndrome. Excessive activity of either the pituitary or the adrenal gland can cause the disease. To determine which gland has abnormal activity in a particular patient, doctors use the drug dexamethasone, a synthetic glucocorticoid that blocks ACTH (adrenocorticotropic hormone) release.

Based on the graph, which gland is affected in the patient with Cushing syndrome and what is the reasoning behind your answer?

8. Here is the final reaction in the citric acid cycle. It shows the regeneration of oxaloacetate.

After studying the reaction, determine which of the following statements is correct.

9. Which of the following statements about the DNA in one of your liver cells is correct?

10. Two genes (B and E) determine coat color in Labrador retrievers. Alleles B and b code for how much melanin is present. The dominant allele B codes for black fur, the recessive allele b codes for brown hair. A second gene consisting of two alleles, E and e, codes for the deposition of pigment in the hair. In this case, the alleles for pigment deposition (E or e) are said to be epistatic to the gene that codes for black or brown pigment. If the dominant allele (E) is not present, regardless of the genotype at the black/brown locus, the animal's fur will be yellow.

Which of the following statements is correct about the genetics of coat color in Labradors?

11. Within a cell, the amount of protein synthesized using a given mRNA molecule depends in part on which of the following?

12. Oxygen is carried in the blood by the respiratory pigment hemoglobin, which can combine loosely with four oxygen molecules, forming the molecule oxyhemoglobin. To function properly, hemoglobin must bind to oxygen in the lungs and drop it off at body cells. The more easily the hemoglobin binds to oxygen in the lungs, the more difficult the oxygen is to unload at the body cells. Here is a graph showing two different saturation-dissociation curves for one type of hemoglobin at two different pH levels.

Based on your knowledge of biology and the information in this graph, which statement about the hemoglobin curves is correct?