Question 1

Which of the following best describes the role of the electron transport chain (ETC) in cellular respiration?

Accepted Answer

It creates a proton gradient across the inner mitochondrial membrane, which drives ATP synthesis via ATP synthase.

Question 2

During glycolysis, which of the following statements is TRUE regarding the two phases?

Accepted Answer

The energy investment phase uses ATP, while the energy payoff phase produces ATP and NADH.

Question 3

If a mutation inhibits the function of phosphofructokinase, a key regulatory enzyme in glycolysis, what is the most likely consequence?

Accepted Answer

Glycolysis will be halted, leading to decreased ATP and pyruvate production.

Question 4

Which of the following is a correct summary of the inputs and outputs of the citric acid cycle for one molecule of acetyl CoA?

Accepted Answer

Inputs: Acetyl CoA, NAD+, FAD, ADP, Pi; Outputs: CO2, NADH, FADH2, ATP

Question 5

Which equation correctly represents the overall process of cellular respiration?

Accepted Answer

$$\mathrm{C}_6\mathrm{H}_{12}\mathrm{O}_6 + 6\ \mathrm{O}_2 ightarrow 6\ \mathrm{CO}_2 + 6\ \mathrm{H}_2\mathrm{O} + 	ext{energy}$$

Question 6

In the absence of oxygen, muscle cells can continue to produce ATP by converting pyruvate into which molecule, and what is the main purpose of this conversion?

Accepted Answer

Lactate; to regenerate NAD+ for glycolysis to continue

Question 7

Which of the following best explains the difference between substrate-level phosphorylation and oxidative phosphorylation?

Accepted Answer

Substrate-level phosphorylation transfers a phosphate group directly from a substrate to ADP, while oxidative phosphorylation uses a proton gradient generated by the electron transport chain to drive ATP synthesis.

Question 8

A patient is exposed to a toxin that specifically inhibits ATP synthase. Which of the following would you expect to occur in their cells?

Accepted Answer

A proton gradient would still be established, but ATP production via oxidative phosphorylation would decrease.

Question 9

Which of the following statements about the light reactions of photosynthesis is correct?

Accepted Answer

They require water and light, producing ATP, NADPH, and O2.

Question 10

During the Calvin cycle, which molecule acts as the enzyme responsible for carbon fixation, and what is its significance?

Accepted Answer

Rubisco; it catalyzes the incorporation of CO2 into organic molecules.

Question 11

Given the overall formula for photosynthesis: $$6\ \mathrm{CO}_2 + 6\ \mathrm{H}_2\mathrm{O} + 	ext{light energy} ightarrow \mathrm{C}_6\mathrm{H}_{12}\mathrm{O}_6 + 6\ \mathrm{O}_2$$, which molecule is oxidized and which is reduced?

Accepted Answer

H2O is oxidized; CO2 is reduced.

Question 12

If a plant's photosystem II (PSII) is damaged, which of the following would most likely occur?

Accepted Answer

O2 production would decrease, and the electron transport chain would be disrupted.

Question 13

Which of the following best describes the function of pigments such as chlorophyll in photosynthesis?

Accepted Answer

They absorb light energy, which excites electrons for use in the light reactions.

Question 14

Which of the following statements about cell communication is correct?

Accepted Answer

Cadherins mediate direct cell-cell adhesion in animal tissues.

Question 15

Which of the following is TRUE regarding the difference between lipid-soluble and lipid-insoluble signaling molecules?

Accepted Answer

Lipid-insoluble signals require membrane-bound receptors, while lipid-soluble signals can diffuse through the membrane and bind intracellular receptors.

Question 16

A mutation causes a G-protein coupled receptor (GPCR) to remain active even in the absence of a signal. What is the most likely cellular consequence?

Accepted Answer

The downstream signaling pathway will be constitutively active, potentially leading to abnormal cell behavior.

Question 17

Which of the following best describes the Notch signaling pathway?

Accepted Answer

It is a form of direct cell-to-cell communication where the receptor is activated by contact with a ligand on an adjacent cell.

Question 18

Which of the following is a correct comparison between enzyme-linked receptors and G-protein coupled receptors (GPCRs)?

Accepted Answer

GPCRs activate G-proteins, while enzyme-linked receptors often have intrinsic kinase activity.

Question 19

If a cell is unable to deactivate a signaling pathway after the signal is removed, what is the most likely outcome?

Accepted Answer

The cell may continue to respond as if the signal is present, potentially leading to uncontrolled growth or other dysfunctions.

Cellular Respiration, Photosynthesis, and Cell Communication: Core Concepts and Pathways

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