Unit 3: Cellular Energetics
Biology · Unit 3 · Paper 3

Cellular Energetics unit test

A test on this unit alone, marked as a percentage and a letter grade — for the test your class is actually sitting, rather than for May. Answer everything, then submit once: seeing the answer to question 3 before attempting question 4 makes the final percentage meaningless.

Paper 1Paper 2Paper 3
Each paper is built from this unit’s 40 terms and is the same for everyone, so a teacher can assign “Unit 3, Paper 3” and every student sits the identical test. Multiple choice is marked objectively; the written sections you mark yourself against the model answer and rubric.
Suggested time 36 min 33 points0/17 attempted
1

Calvin cycle

2

Light-dependent reactions

3

Activation energy

4

Lab: Cellular Respiration

5

Chemiosmosis

6

Enzyme specificity

7

Absorption spectrum vs action spectrum

8

Electron transport chain

9

Allosteric regulation

10

Why oxygen matters

11

Proton gradient

12

Photolysis of water

Short answer 1. Define or explain: Feedback inhibition

3 pts

Short answer 2. Define or explain: Rubisco and photorespiration

3 pts

Short answer 3. Define or explain: Photosystems II and I

3 pts

Short answer 4. Define or explain: Glycolysis

3 pts

Free response

9 pts

Elevated CO2 increases the rate of photosynthesis and growth in plants. Scientists examining the mechanism found that plants exposed to elevated CO2 make more chloroplasts per cell. To test whether elevated CO2 has a similar effect on mitochondria, they counted mitochondria per unit of cell area in six species grown at normal and at elevated CO2. TABLE 1. AVERAGE NUMBER OF MITOCHONDRIA PER 100 μm² OF CELL AREA (± 2SE of the mean) Species Normal CO2 Elevated CO2 1 1.0 ± 0.10 1.6 ± 0.10 2 0.4 ± 0.05 0.9 ± 0.08 3 0.5 ± 0.07 0.9 ± 0.10 4 0.3 ± 0.03 0.6 ± 0.06 5 0.7 ± 0.06 1.5 ± 0.22 6 1.3 ± 0.15 2.4 ± 0.22

(a) Describe the role of the inner mitochondrial membrane in cellular respiration.

(b)(i) The released exam supplies a grid. State what type of graph represents these data appropriately, and why that type fits data of this kind.

(b)(ii) State what belongs on each axis, including units, and what the error bars on each mean would represent.

(b)(iii) State how you would plot the two CO2 conditions for each species so that the comparison the question asks for is visible.

(b)(iv) Determine which species show(s) a difference in the number of mitochondria between normal and elevated levels of CO2.

(c) Based on the data in Table 1, describe the relationship between the level of CO2 and the average number of mitochondria per unit area of a cell.

(d)(i) A plant of a normally green-leaved species has leaves with white stripes, caused by a mutation in mitochondrial DNA that interferes with chloroplast development. Scientists cross plants using pollen from the white-striped plant and ovules from a green-leaved plant. Predict the leaf phenotype(s) of the offspring.

(d)(ii) Provide reasoning to justify your prediction in (d)(i).

(d)(iii) Explain why plants with the same genotype are able to differ in the structure and/or number of certain organelles in response to changes in atmospheric CO2.