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AP Biology

AP Bio Unit 2 Topics 2.2 2.4 Quiz 2

Shared by ashtont · Oct 4, 2026 · 0 plays

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32 questions across 4 sections. After every answer you’ll see why each choice is right or wrong, not just the one you picked.

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Sample questions

Open a question to see the answer choices and the correct answer.

A 1 x 1 x 8 cm block and a 2 x 2 x 2 cm cube have the same volume (8 cm^3). How do their SA:V ratios compare?
  1. A. Block 4.25 cm^-1, cube 3.0 cm^-1; the block exchanges better ✓
  2. B. Block 3.0 cm^-1, cube 4.25 cm^-1; the cube exchanges better
  3. C. Both 3.0 cm^-1, because equal volumes give equal SA:V ratios
  4. D. Block 2.0 cm^-1, cube 3.0 cm^-1; length lowers the SA:V ratio

Correct answer: A. Block SA = 2(8)+2(8)+2(1) = 34 cm^2, so 34/8 = 4.25; cube 24/8 = 3.0. Stretching a shape raises SA:V without changing volume.

In the sweet potato lab, a student records only the DEPTH of the bleached layer, finds about 0.4 cm in all three cubes, and concludes SA:V has no effect. What is the flaw?
  1. A. Depth stays constant; the fraction of volume reached is what varies ✓
  2. B. Bleach diffuses faster into large cubes, hiding the real difference
  3. C. Bleach destroys membranes, so no real diffusion was occurring at all
  4. D. Depth should vary with SA:V, so the measurements must be in error

Correct answer: A. Diffusion goes about the same distance per unit time in every cube. The small cube's 0.4 cm layer is ~99% of its volume; the 3 cm cube's is ~61%. Percent diffusion is the right dependent variable.

What is the SA:V ratio of a spherical cell with a radius of 3 um?
  1. A. 0.33 um^-1
  2. B. 1.0 um^-1 ✓
  3. C. 3.0 um^-1
  4. D. 9.0 um^-1

Correct answer: B. Sphere SA:V = 3/r = 3/3 = 1.0. (SA = 36pi ~ 113.1 um^2; V = 36pi ~ 113.1 um^3.)

Cell A is a cube with side 2 um. Cell B is a sphere with radius 2 um. Which statement about their SA:V ratios is correct?
  1. A. Sphere: 3.0 um^-1; cube: 1.5 um^-1, so the sphere exchanges better
  2. B. They are equal, since both have a size measurement of 2 um
  3. C. Cube: 3.0 um^-1; sphere: 1.5 um^-1, so the cube exchanges better ✓
  4. D. Sphere: 0.75 um^-1; cube: 0.33 um^-1, so the sphere exchanges better

Correct answer: C. Cube 6/s = 6/2 = 3.0; sphere 3/r = 3/2 = 1.5. The sphere is also much bigger (4 um across).

If metabolic rate PER GRAM is plotted against body mass for many mammal species, which pattern is expected?
  1. A. A rising curve: larger mammals use more energy per gram
  2. B. A flat line: every mammal uses the same energy per gram
  3. C. A falling curve: larger mammals use less energy per gram ✓
  4. D. A peak at medium size, where SA:V is at its very highest

Correct answer: C. Larger animals have a lower SA:V, lose heat more slowly per gram, and need less metabolic heat per gram.