Question 1

Which of the following best explains why mitochondria and chloroplasts are considered evidence for the endosymbiont theory?

Accepted Answer

They have their own circular DNA and ribosomes, and divide independently of the cell.

Question 2

A researcher observes that a cell's surface-area-to-volume ratio decreases as the cell grows. What is the most likely consequence of this change?

Accepted Answer

The cell will struggle to exchange enough materials to meet its metabolic needs.

Question 3

Which of the following scenarios would most directly disrupt the production of ATP in mitochondria?

Accepted Answer

A drug that makes the inner mitochondrial membrane permeable to H⁺ ions.

Question 4

A plant cell is placed in a solution and its plasma membrane pulls away from the cell wall (plasmolysis). Which statement best explains this observation?

Accepted Answer

The solution is hypertonic to the cell, causing water to leave.

Question 5

Which of the following best describes the role of the sodium-potassium pump in animal cells?

Accepted Answer

It moves 3 Na⁺ out and 2 K⁺ in, using ATP hydrolysis.

Question 6

Which equation correctly represents the change in free energy for a chemical reaction?

Accepted Answer

$$\Delta G = \Delta H - T\Delta S$$

Question 7

A competitive inhibitor is added to an enzyme-catalyzed reaction. Which of the following would most likely restore the reaction rate?

Accepted Answer

Adding more substrate.

Question 8

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

Accepted Answer

The ETC pumps H⁺ ions to create a gradient used by ATP synthase.

Question 9

If a poison blocks the transfer of electrons from cytochrome a₃ to O₂ in mitochondria, what is the immediate effect?

Accepted Answer

Electron flow stops and the H⁺ gradient dissipates.

Question 10

Which molecule is reduced during aerobic cellular respiration?

Accepted Answer

O₂

Question 11

Which process in photosynthesis is responsible for the release of O₂?

Accepted Answer

Splitting of water in photosystem II

Question 12

Why is the action spectrum of photosynthesis broader than the absorption spectrum of chlorophyll a?

Accepted Answer

Accessory pigments absorb additional wavelengths and transfer energy to chlorophyll a.

Question 13

A plant cell is exposed to a drug that makes the thylakoid membrane leaky to H⁺ ions. Which output of the light reactions will decrease most directly?

Accepted Answer

ATP synthesis

Question 14

Which adaptation allows C₄ plants like corn to avoid photorespiration in hot, dry climates?

Accepted Answer

They use PEP carboxylase to fix CO₂ in mesophyll cells and concentrate it in bundle-sheath cells.

Question 15

Which of the following best explains how cells can build highly ordered structures without violating the second law of thermodynamics?

Accepted Answer

Cells release heat and simple molecules, increasing the entropy of their surroundings.

Question 16

Which of the following is a correct comparison between cellular respiration and photosynthesis?

Accepted Answer

Both processes use an electron transport chain, a proton gradient, and ATP synthase.

Question 17

A patient with a genetic defect lacks functional LDL receptors. Which cellular process is most directly affected?

Accepted Answer

Receptor-mediated endocytosis

Question 18

Which formula correctly calculates the solute potential ($$\Psi_S) $$for a solution in plant cells?

Accepted Answer

$$\Psi_S = -iCRT$$

Question 19

Which of the following would most likely occur if the plasma membrane of a neuron became highly permeable to Na⁺ ions?

Accepted Answer

The membrane potential would decrease as Na⁺ enters, disrupting the electrochemical gradient.

Question 20

Which of the following best describes the main function of fermentation in muscle cells during intense exercise?

Accepted Answer

To regenerate NAD⁺ so glycolysis can continue producing ATP.

Campbell Biology Chapters 6–10: Cell Structure, Membrane Function, Metabolism, Respiration, and Photosynthesis

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