Question 1

Which of the following best explains why cells are generally small in size?

Accepted Answer

Smaller cells have a higher surface area-to-volume ratio, which facilitates efficient exchange of materials with their environment.

Question 2

A scientist is using a microscope to observe the detailed internal structure of mitochondria. Which type of microscope should she use and why?

Accepted Answer

Transmission electron microscope (TEM), because it provides high-resolution images of internal cell structures.

Question 3

Which of the following structures is present in plant cells but not in animal cells?

Accepted Answer

Cell wall

Question 4

A mutation causes a cell to lack functional peroxisomes. Which of the following processes would be most directly affected?

Accepted Answer

Breakdown of fatty acids and detoxification of hydrogen peroxide

Question 5

Which of the following best describes the role of the sodium-potassium pump ($$\mathrm{Na^+-K^+-ATPase}) in $$animal cells?

Accepted Answer

It uses ATP to move $$3\ \mathrm{Na^+}$$ ions out of the cell and $$2\ \mathrm{K^+}$$ ions into the cell, maintaining the electrochemical gradient.

Question 6

A red blood cell is placed in a hypotonic solution. What will most likely happen to the cell, and why?

Accepted Answer

It will swell and possibly burst because water enters the cell by osmosis.

Question 7

Which of the following statements about the fluid mosaic model of the plasma membrane is correct?

Accepted Answer

Phospholipids and proteins can move laterally within the layer, contributing to membrane fluidity.

Question 8

Which of the following best describes the difference between competitive and allosteric inhibition of enzymes?

Accepted Answer

Competitive inhibitors bind to the active site, while allosteric inhibitors bind to a different site, changing the enzyme's shape.

Question 9

During glycolysis, what is the net gain of ATP and NADH molecules per molecule of glucose?

Accepted Answer

$$2$$ ATP and $$2$$ NADH

Question 10

Which of the following equations correctly represents the change in free energy ($$\Delta G) $$for a chemical reaction?

Accepted Answer

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

Question 11

A cell is observed to engulf large particles such as bacteria. Which process is being used?

Accepted Answer

Phagocytosis

Question 12

Which of the following best explains why ATP hydrolysis is often coupled to endergonic reactions in cells?

Accepted Answer

ATP hydrolysis releases free energy ($$\Delta G \u003c 0$$), which can drive non-spontaneous reactions.

Question 13

Which of the following is a function of the Golgi apparatus in eukaryotic cells?

Accepted Answer

Modifying, sorting, and packaging proteins for secretion or delivery to other organelles

Question 14

A patient is diagnosed with a genetic disorder that affects the structure of microtubules. Which of the following cellular processes is most likely to be impaired?

Accepted Answer

Movement of cilia and flagella

Question 15

Which of the following statements about oxidative phosphorylation is correct?

Accepted Answer

It uses the energy from a proton gradient across the inner mitochondrial membrane to synthesize ATP via ATP synthase.

Question 16

Which of the following best describes the role of NAD+ in cellular respiration?

Accepted Answer

It acts as an electron carrier, becoming reduced to NADH during glycolysis and the Krebs cycle.

Question 17

A plant cell is placed in a hypertonic solution. What will happen to the cell and why?

Accepted Answer

The cell will lose water, causing the plasma membrane to pull away from the cell wall (plasmolysis).

Question 18

Which of the following is an example of feedback inhibition in a metabolic pathway?

Accepted Answer

The end product of a pathway binds to an enzyme that acts early in the pathway, inhibiting its activity.

Question 19

Which of the following best describes the main 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 and ATP synthase.

Question 20

A cell is exposed to a toxin that irreversibly inhibits all ATP synthase enzymes. Which process will be most directly affected?

Accepted Answer

Production of ATP during chemiosmosis in mitochondria

Cell Structure, Membrane Function, and Metabolism: Study Notes for General Biology

Guida di studio - Domande di pratica

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