Q: The overall equation for aerobic cellular respiration is:

$$C_6H_{12}O_6$ + 6 \mathrm{O}_2 \rightarrow 6 \mathrm{CO}_2 + 6 \mathrm{H}_2\mathrm{O} + \text{energy}$$

Question 1

Which of the following best describes the relationship between photosynthesis and cellular respiration in terms of energy and redox reactions?

Accepted Answer

Photosynthesis reduces carbon dioxide to glucose using light energy, while respiration oxidizes glucose to carbon dioxide, releasing energy.

Question 2

The overall equation for aerobic cellular respiration is:

Accepted Answer

$$C_6H_{12}O_6$ + 6 \mathrm{O}_2 ightarrow 6 \mathrm{CO}_2 + 6 \mathrm{H}_2\mathrm{O} + 	ext{energy}$$

Question 3

During the light-dependent reactions of photosynthesis, which of the following occurs as electrons move through the electron transport chain (ETC)?

Accepted Answer

Electrons move from water to NADP+, generating a proton gradient used to synthesize ATP.

Question 4

Which of the following best explains why the thylakoid lumen develops a low pH during the light reactions of photosynthesis?

Accepted Answer

Protons (H$$^+) $$are pumped from the stroma into the thylakoid lumen as electrons move through the ETC.

Question 5

Which of the following statements about the Calvin cycle is correct?

Accepted Answer

ATP is used in both the reduction and regeneration phases, while NADPH is used only in the reduction phase.

Question 6

Which of the following best describes the role of water in photosynthesis?

Accepted Answer

Water donates electrons to photosystem II, resulting in the release of O$$_2 as a $$byproduct.

Question 7

Which of the following is a key difference between substrate-level phosphorylation and oxidative phosphorylation?

Accepted Answer

Substrate-level phosphorylation directly transfers a phosphate group from a substrate to ADP, while oxidative phosphorylation uses a proton gradient to drive ATP synthesis via ATP synthase.

Question 8

A plant is exposed to light that is primarily green in wavelength. Which of the following is most likely to occur?

Accepted Answer

Photosynthesis will be less efficient because chlorophyll reflects green light rather than absorbing it.

Question 9

Which of the following best explains why showing an arrow directly from the electron transport chain (ETC) to ATP production in diagrams of photosynthesis is misleading?

Accepted Answer

The ETC creates a proton gradient, and ATP is produced as protons flow back through ATP synthase, not directly by the ETC.

Question 10

Which of the following statements about Rubisco is correct?

Accepted Answer

Rubisco can catalyze reactions with both CO$$_2$$ and O$$_2$$, which can reduce the efficiency of photosynthesis.

Question 11

Which of the following best describes the main advantage of the C4 pathway in plants?

Accepted Answer

It spatially separates carbon fixation from the Calvin cycle, reducing photorespiration by concentrating CO$$_2$$ around Rubisco.

Question 12

During glycolysis, which molecule contains the most energy from the original glucose molecule at the end of the pathway?

Accepted Answer

Pyruvate

Question 13

Which of the following statements about the electron transport chain (ETC) in mitochondria is correct?

Accepted Answer

O$$_2$$ acts as the final electron acceptor, forming water.

Question 14

Which of the following best explains how fermentation allows glycolysis to continue in the absence of oxygen?

Accepted Answer

Fermentation regenerates NAD$$^+$$ from NADH, allowing glycolysis to continue producing ATP.

Question 15

Which of the following is a correct comparison between cyclic and noncyclic electron flow in the light reactions of photosynthesis?

Accepted Answer

Cyclic electron flow produces ATP but not NADPH or O$$_2$$, while noncyclic flow produces ATP, NADPH, and O$$_2.$$

Question 16

A mutation causes a plant to lack functional ATP synthase in its thylakoid membranes. Which of the following would most likely be observed?

Accepted Answer

The plant would be unable to produce ATP in the chloroplast, severely limiting the Calvin cycle.

Question 17

Which of the following best explains why fats and phospholipids enter the cellular respiration pathway through the same intermediates?

Accepted Answer

Both are hydrolyzed to fatty acids and glycerol, which enter at different points in the pathway based on their chemical structure.

Question 18

Which of the following is a key reason why feedback inhibition of phosphofructokinase (PFK) is an effective regulatory mechanism in glycolysis?

Accepted Answer

PFK catalyzes an early, irreversible step, so its inhibition prevents unnecessary breakdown of glucose when ATP is abundant.

Question 19

Which of the following best describes the energy conversions that occur during the light reactions of photosynthesis?

Accepted Answer

Light energy is converted to chemical energy stored in ATP and NADPH.

Question 20

In which cellular compartment does the citric acid cycle occur in eukaryotes, and what is the main function of this cycle?

Accepted Answer

Mitochondrial matrix; to oxidize acetyl-CoA and generate NADH, FADH$$_2$$, and ATP

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