Question 1

Which of the following is a major structural difference between prokaryotic and eukaryotic cells?

Accepted Answer

Prokaryotic cells lack a membrane-bound nucleus, while eukaryotic cells possess one.

Question 2

Which organelle is primarily responsible for modifying, sorting, and packaging proteins for secretion in eukaryotic cells?

Accepted Answer

Golgi apparatus

Question 3

During receptor-mediated endocytosis, which of the following best describes the process?

Accepted Answer

Specific molecules are recognized by cell surface receptors and internalized in vesicles.

Question 4

Which of the following cell-cell connections allows direct transfer of ions and small molecules between adjacent animal cells?

Accepted Answer

Gap junctions

Question 5

A scientist measures the activity of an enzyme in bamboo shark muscle at different temperatures. At 37°C, the enzyme activity is high, but at 50°C, activity drops sharply. Which explanation best fits these results?

Accepted Answer

The enzyme denatures at higher temperatures, losing its functional shape.

Question 6

Which equation correctly represents the relationship between Gibbs free energy ($$\Delta G$$), enthalpy ($$\Delta H$$), entropy ($$\Delta S$$), and temperature ($$T$$)?

Accepted Answer

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

Question 7

If a reaction has $$\Delta G \u003c 0$$, which of the following statements is true?

Accepted Answer

The reaction is exergonic and can occur spontaneously.

Question 8

Which process is used by cells to drive endergonic reactions by coupling them to exergonic reactions?

Accepted Answer

Phosphorylation

Question 9

Which of the following best describes competitive inhibition of an enzyme?

Accepted Answer

A molecule binds to the active site, preventing substrate binding.

Question 10

Which step of cellular respiration occurs in the cytosol of eukaryotic cells?

Accepted Answer

Glycolysis

Question 11

Which of the following is a correct summary of the overall inputs and outputs of aerobic cellular respiration?

Accepted Answer

Inputs: glucose and oxygen; Outputs: carbon dioxide, water, and ATP

Question 12

Why do cells carry out fermentation when oxygen is unavailable?

Accepted Answer

To regenerate NAD$$^+ so $$glycolysis can continue producing ATP.

Question 13

Which pigment is responsible for capturing light energy in plants, and what is its primary function?

Accepted Answer

Chlorophyll; it absorbs light energy to drive photosynthesis.

Question 14

Where in the plant cell do the light-dependent reactions of photosynthesis occur?

Accepted Answer

Thylakoid membranes of the chloroplast

Question 15

Which enzyme is essential for carbon fixation in the Calvin cycle, and what is a consequence of its inefficiency?

Accepted Answer

Rubisco; photorespiration reduces the efficiency of photosynthesis.

Question 16

Which of the following best describes the difference between catabolic and anabolic pathways?

Accepted Answer

Catabolic pathways break down molecules and release energy; anabolic pathways build molecules and require energy.

Question 17

Which of the following is a function of the extracellular matrix (ECM) in animal cells?

Accepted Answer

Provides structural support and mediates cell signaling.

Question 18

A mutation causes a cell to lose the ability to form tight junctions. Which outcome is most likely?

Accepted Answer

The cell will lose its ability to prevent leakage of molecules between adjacent cells.

Question 19

Which of the following best explains why substrate saturation limits the rate of enzyme-catalyzed reactions?

Accepted Answer

All enzyme active sites are occupied, so increasing substrate concentration does not increase reaction rate.

General Biology: Cell Structure, Cell Communication, Metabolism, Respiration, and Photosynthesis Study Guide

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