Question 1

Which of the following best describes the role of cholesterol in the fluid mosaic model of the plasma membrane?

Accepted Answer

Cholesterol stabilizes membrane fluidity by preventing extremes of rigidity and fluidity.

Question 2

A cell placed in a hypertonic solution will most likely undergo which process, and why?

Accepted Answer

It will shrink because water leaves the cell to balance solute concentrations.

Question 3

Which equation correctly represents the change in free energy ($$\Delta G) $$for a chemical reaction, and what does a negative $$\Delta G$$ indicate?

Accepted Answer

$$\Delta G = \Delta H - T\Delta S$$; a negative $$\Delta G$$ means the reaction is spontaneous and exergonic.

Question 4

During cellular respiration, which molecule acts as the final electron acceptor in the electron transport chain?

Accepted Answer

Oxygen ($$O_2)$$

Question 5

Which process directly produces the most ATP during aerobic cellular respiration?

Accepted Answer

Oxidative Phosphorylation

Question 6

A competitive inhibitor affects enzyme activity by:

Accepted Answer

Binding to the active site and preventing substrate binding.

Question 7

Which of the following is a correct sequence of events in signal transduction involving a G-protein coupled receptor (GPCR)?

Accepted Answer

Ligand binds GPCR → G-protein exchanges GDP for GTP → G-protein activates effector enzyme → Second messenger produced

Question 8

Which of the following best explains why photosynthesis is considered an endergonic process?

Accepted Answer

It requires an input of energy (light) to convert $$CO_2$$ and $$H_2O$$ into glucose.

Question 9

In the Calvin Cycle, which enzyme catalyzes the fixation of $$CO_2 to $$RuBP?

Accepted Answer

Rubisco

Question 10

A mutation causes a channel protein in a neuron to remain open. What is the most likely effect on the cell's membrane potential?

Accepted Answer

Ions will flow freely, disrupting the electrochemical gradient and altering the membrane potential.

Question 11

Which of the following statements about ATP synthase is correct?

Accepted Answer

ATP synthase synthesizes ATP using the energy from a proton gradient across the mitochondrial inner membrane.

Question 12

Which of the following is NOT a function of membrane proteins?

Accepted Answer

Providing structural support to the cell wall

Question 13

Which process is responsible for the uptake of large particles, such as bacteria, by immune cells?

Accepted Answer

Phagocytosis

Question 14

Which of the following best describes the difference between C3 and C4 photosynthesis?

Accepted Answer

C4 plants spatially separate $$CO_2$$ fixation and the Calvin Cycle to minimize photorespiration.

Question 15

Which of the following equations correctly represents the overall reaction for aerobic cellular respiration?

Accepted Answer

$$C_6H_{12}O_6$ + 6O_2 ightarrow 6CO_2 + 6H_2O + 	ext{energy}$$

Question 16

Which of the following is a real-world example of signal transduction involving second messengers?

Accepted Answer

Insulin binding to its receptor and activating a phosphorylation cascade involving cAMP.

Question 17

Which of the following statements about apoptosis is correct?

Accepted Answer

Apoptosis is a regulated process that removes damaged or unnecessary cells without causing inflammation.

Question 18

Which of the following best explains the function of a catalyst in a chemical reaction?

Accepted Answer

A catalyst lowers the activation energy, increasing the rate of the reaction without being consumed.

Question 19

Which of the following is a correct description of the role of NADH in cellular respiration?

Accepted Answer

NADH donates electrons to the electron transport chain, helping generate ATP.

Core Concepts in General Biology: Cell Structure, Energy, Metabolism, and Communication

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