AP Biology Practice Exam: Full-Length Multiple Choice

Topic 1.1 · Concept check

Water can absorb a lot of heat before its temperature rises much. Which explanation is best?

Topic 1.2 · Experiment

Bacteria are grown in a medium where the only sulfur available is radioactive sulfur-35. After several generations, which type of molecule in the bacteria will contain the most radioactive label?

Topic 1.3 · Concept check

When two amino acids are joined to form a dipeptide, which of the following also happens?

Topic 1.4 · Apply it

Starch and cellulose are both polymers of glucose, yet humans can digest starch but not cellulose. Which explanation is best supported?

Topic 1.5 · Data analysis

Which claim best explains the difference between fats A and B?

Topic 1.6 · Concept check

Which difference between DNA and RNA is correct?

Topic 2.1 · Apply it

Cells in the pancreas secrete large amounts of digestive enzymes, which are proteins. Which organelles would you expect these cells to have in unusually large amounts?

Topic 2.1 · Concept check

Which statement about ribosomes is correct?

Topic 2.3 · Concept check

Which substance can most easily cross a phospholipid bilayer without help from a membrane protein?

Topic 2.5 · Concept check

The sodium–potassium pump moves 3 Na⁺ out of a cell and 2 K⁺ into the cell for each ATP used. Which statement describes this transport?

Topic 2.6 · Data analysis

Which explanation best accounts for the uptake rate levelling off at high glucose concentrations?

Topic 2.7 · Data analysis

A plant cell has a water potential of −0.6 MPa. It is placed in a solution with a water potential of −0.2 MPa.

Which way will water move?

Topic 2.9 · Apply it

Lysosomes keep powerful digestive enzymes at an acidic pH, separated from the rest of the cytoplasm. What advantage does this give the cell?

Topic 3.1 · Concept check

How does an enzyme speed up a chemical reaction?

Topic 3.1 · Experiment

A molecule slows an enzyme-catalysed reaction by binding to the enzyme's active site. A student adds much more substrate and the reaction rate returns almost to normal. What kind of inhibitor is this most likely to be?

Topic 3.2 · Apply it

Pepsin works best at about pH 2 in the stomach. When stomach contents move into the small intestine, where the pH is about 7–8, pepsin activity drops. Why?

Topic 3.3 · Concept check

Cells use ATP to drive reactions that would not happen on their own. How does ATP usually do this?

Topic 3.4 · Experiment

Leaf disks are vacuum-infiltrated so they sink in a baking-soda solution, then placed under lamps of different brightness. Disks under the brightest lamp float soonest. Which explanation is best?

Topic 3.4 · Concept check

Which statement correctly describes the Calvin cycle?

Topic 3.5 · Experiment

Cyanide blocks the final protein complex of the electron transport chain, so electrons can no longer be passed to oxygen. Which outcome is most likely in a cell exposed to cyanide?

Topic 3.5 · Concept check

What is the final electron acceptor in aerobic cellular respiration?

Topic 4.1 · Concept check

Insulin is released by cells in the pancreas, travels through the bloodstream, and affects muscle and liver cells. What type of signaling is this?

Topic 4.2 · Apply it

Testosterone is a steroid hormone that binds to a receptor inside its target cells. Why can it reach this receptor while a protein hormone such as insulin cannot?

Topic 4.3 · Apply it

A very small amount of epinephrine can cause liver cells to release a large amount of glucose within seconds. Which feature of signal transduction best explains this?

Topic 4.3 · Apply it

Ras is a G protein that relays signals from growth factor receptors. A mutation makes Ras unable to hydrolyse GTP, so it stays in its active form. What is the most likely effect on the cell?

Topic 4.4 · Apply it

TSH from the pituitary stimulates the thyroid to release thyroid hormone. High levels of thyroid hormone reduce TSH release. If a person takes thyroid hormone pills, what will most likely happen to their TSH level?

Topic 4.5 · Concept check

During which phase of the cell cycle is DNA replicated?

Topic 4.5 · Data analysis

Which phases are the cells in group Z most likely in?

Topic 4.6 · Concept check

Which statement best describes how cyclins and cyclin-dependent kinases (CDKs) control the cell cycle?

Topic 5.1 · Concept check

Which statement correctly describes the result of meiosis in a diploid organism?

Topic 5.1 · Apply it

A person with Down syndrome has three copies of chromosome 21. Which error during gamete formation can cause this?

Topic 5.2 · Concept check

During which stage does crossing over occur, and what does it produce?

Topic 5.3 · Data analysis

A student calculates chi-square to test whether the results fit a 3:1 ratio. The critical value for 1 degree of freedom at p = 0.05 is 3.84. Which conclusion is correct?

Topic 5.4 · Data analysis

In a test cross, only 8% of offspring show recombinant combinations of two traits, instead of the 50% expected for independent assortment. What is the best explanation?

Topic 5.5 · Apply it

Cuttings from one hydrangea plant are planted in soils with different pH. The flowers are blue in acidic soil and pink in alkaline soil. What does this show?

Topic 6.1 · Data analysis

In a sample of double-stranded DNA, 30% of the bases are adenine. What percentage are guanine?

Topic 6.2 · Experiment

Bacteria are grown for many generations with heavy nitrogen (¹⁵N), then moved to normal nitrogen (¹⁴N) and allowed to replicate their DNA exactly once. If replication is semiconservative, what will DNA extracted from them look like when separated by density?

Topic 6.3 · Data analysis

A eukaryotic gene is 8,000 nucleotides long, but the mature mRNA made from it is about 3,000 nucleotides long. What best explains the difference?

Topic 6.3 · Apply it

A template DNA strand reads 3′-TAC-5′. Which mRNA sequence is transcribed from it?

Topic 6.4 · Apply it

Which tRNA anticodon pairs with the mRNA codon 5′-AUG-3′?

Topic 6.5 · Apply it

E. coli is grown with lactose and no glucose. What happens at the lac operon?

Topic 6.6 · Concept check

A person's nerve cells and muscle cells look and work very differently. What best explains this?

Topic 6.7 · Apply it

Which mutation near the start of a protein-coding sequence is most likely to change the protein the most?

Topic 7.1 · Concept check

Which statement about evolution by natural selection is accurate?

Topic 7.2 · Apply it

In a region where tree bark was darkened by soot, dark-coloured moths became much more common than light-coloured moths over several decades. Which explanation is best?

Topic 7.3 · Concept check

Broccoli, cabbage and kale were all bred from a single species of wild mustard. What process produced these varieties?

Topic 7.4 · Apply it

A storm randomly kills 90% of a small island population of lizards. Afterwards, an allele that was rare has become common, even though it gives no survival advantage. What best explains this?

Topic 7.5 · Concept check

Which condition is required for a population to stay in Hardy–Weinberg equilibrium?

Topic 7.6 · Apply it

A human arm, a bat wing and a whale flipper have the same arrangement of bones, though they are used differently. What do these structures most strongly suggest?

Topic 7.7 · Concept check

Which observation provides strong evidence that all living organisms share a common ancestor?

Topic 7.9 · Data analysis

Which conclusion about how species A, B and C are related is best supported by the data?

Topic 7.10 · Apply it

Two populations of frogs live in the same pond. One breeds in early spring and the other in late spring, so they never interbreed. What kind of reproductive barrier is this?

Topic 7.11 · Apply it

A crop is grown worldwide from genetically identical clones. A new fungal disease appears. Why is this crop at greater risk than a wild population of the same species?

Topic 8.1 · Concept check

Some plants flower only when the night is longer than a critical length. What is this response called?

Topic 8.2 · Data analysis

Producers in an ecosystem capture 10,000 kcal of energy. About how much energy is available to tertiary consumers, the fourth trophic level?

Topic 8.2 · Apply it

A mouse and a lizard have the same body mass. Why does the mouse need much more food per day?

Topic 8.4 · Apply it

A population's growth slows as it approaches the environment's carrying capacity. Which factor most likely causes this?

Topic 8.5 · Apply it

Sea otters eat sea urchins, and sea urchins eat kelp. If sea otters are removed from a coastal ecosystem, what is the most likely result?

Topic 8.5 · Experiment

Which conclusion is best supported by these results?

Topic 8.7 · Data analysis

Which process best explains the pattern in the table?