Question 1

Which statement best describes the 'fluid mosaic model' of the plasma membrane?

Accepted Answer

The plasma membrane is a dynamic structure with proteins and other macromolecules embedded in or attached to a phospholipid bilayer, allowing lateral movement.

Question 2

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

Accepted Answer

It will swell and may burst as water enters the cell.

Question 3

Which of the following best defines facilitated diffusion?

Accepted Answer

Movement of molecules through a membrane via transport proteins, from high to low concentration, without energy input.

Question 4

Which of the following is an example of active transport?

Accepted Answer

Movement of glucose into a cell against its concentration gradient using ATP.

Question 5

What is the main function of ATP in cellular metabolism?

Accepted Answer

To provide energy for cellular work by transferring a phosphate group.

Question 6

Which of the following best describes the difference between exergonic and endergonic reactions?

Accepted Answer

Exergonic reactions release energy ($$\Delta G  0).$$

Question 7

A plant cell is placed in a hypertonic solution. What is the expected outcome?

Accepted Answer

The cell will lose water and undergo plasmolysis.

Question 8

Which of the following statements about membrane proteins is correct?

Accepted Answer

Membrane proteins can function as transporters, receptors, or enzymes.

Question 9

Which of the following is true regarding the second law of thermodynamics?

Accepted Answer

Every energy transfer increases the entropy (disorder) of the universe.

Question 10

Which process requires energy input from ATP?

Accepted Answer

Active transport of sodium ions out of a cell.

Question 11

Which of the following best describes the role of enzymes in chemical reactions?

Accepted Answer

Enzymes decrease the activation energy, speeding up reactions.

Question 12

Which of the following is a competitive inhibitor of an enzyme?

Accepted Answer

A molecule that binds to the active site, blocking substrate binding.

Question 13

Which of the following is an example of negative feedback inhibition?

Accepted Answer

A product of a metabolic pathway inhibits an enzyme earlier in the pathway.

Question 14

Which of the following best describes osmosis?

Accepted Answer

Movement of water across a selectively permeable membrane from low solute concentration to high solute concentration.

Question 15

Which of the following is true about the selectively permeable nature of the plasma membrane?

Accepted Answer

The membrane allows some molecules to pass while restricting others based on size, charge, and polarity.

Question 16

Which of the following is a function of a transport protein in the plasma membrane?

Accepted Answer

Facilitating the movement of specific molecules across the membrane.

Question 17

Which of the following best describes the difference between endocytosis and exocytosis?

Accepted Answer

Endocytosis involves the cell engulfing material, while exocytosis releases material outside the cell.

Question 18

Which of the following best describes activation energy ($$E_a) in a $$chemical reaction?

Accepted Answer

The minimum energy required to start a chemical reaction.

Question 19

A scientist is studying the effect of temperature on enzyme activity. Which of the following is most likely to occur if the temperature is increased beyond the enzyme's optimal range?

Accepted Answer

The enzyme will denature and lose its activity.

Chapter 5: Membrane Structure, Function, and Cellular Energy – Study Guide

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