Q: Which equation correctly represents the hydrolysis of ATP?

$\mathrm{ATP} + \mathrm{H}_2\mathrm{O} \rightarrow \mathrm{ADP} + \mathrm{P}_i + \text{energy}$

Question 1

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

Accepted Answer

Proteins are embedded in a fluid phospholipid bilayer, allowing for diverse functions.

Question 2

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

Accepted Answer

The cell will swell and may lyse due to water influx.

Question 3

Which type of transport requires energy input from the cell?

Accepted Answer

Active transport

Question 4

What is the primary function of aquaporins in the plasma membrane?

Accepted Answer

To facilitate the rapid diffusion of water across the membrane

Question 5

Which equation correctly represents the hydrolysis of ATP?

Accepted Answer

$\mathrm{ATP} + \mathrm{H}_2\mathrm{O} ightarrow \mathrm{ADP} + \mathrm{P}_i + 	ext{energy}$

Question 6

A freshwater Paramecium uses contractile vacuoles to maintain water balance. What is the reason for this adaptation?

Accepted Answer

It lives in a hypotonic environment and must expel excess water to prevent lysis.

Question 7

Which process describes the movement of large molecules out of a cell?

Accepted Answer

Exocytosis

Question 8

How does the second law of thermodynamics explain the diffusion of a solute across a membrane?

Accepted Answer

Diffusion increases entropy by spreading molecules more randomly.

Question 9

Which of the following best describes an exergonic reaction?

Accepted Answer

A reaction that releases energy, such as cellular respiration

Question 10

A cell is actively transporting $\mathrm{Ca}^{2+}$ ions out of its cytoplasm. Where is the concentration of $\mathrm{Ca}^{2+}$ higher?

Accepted Answer

Outside the cell

Question 11

Which membrane protein function is responsible for relaying messages from signaling molecules?

Accepted Answer

Receptor proteins

Question 12

Which of the following is true about facilitated diffusion?

Accepted Answer

It moves substances down their concentration gradient without energy input.

Question 13

What is the role of enzymes in cellular metabolism?

Accepted Answer

They lower the activation energy required for reactions.

Question 14

Which of the following is a correct comparison between competitive and noncompetitive enzyme inhibitors?

Accepted Answer

Competitive inhibitors bind to the active site, while noncompetitive inhibitors bind elsewhere on the enzyme.

Question 15

Which of the following best explains why polar or charged substances require transport proteins to cross the plasma membrane?

Accepted Answer

The hydrophobic core of the phospholipid bilayer prevents their passage.

Question 16

Which process is used by white blood cells to engulf bacteria?

Accepted Answer

Phagocytosis

Question 17

Which of the following is a function of glycoproteins in the plasma membrane?

Accepted Answer

Serving as identification tags recognized by other cells

Question 18

Which equation represents the coupling of exergonic and endergonic reactions via ATP?

Accepted Answer

$	ext{Exergonic reaction releases energy, which is used to drive endergonic reaction:} \quad \mathrm{ATP} ightarrow \mathrm{ADP} + \mathrm{P}_i + 	ext{energy} ightarrow 	ext{cellular work}$

Question 19

A plant cell is placed in an isotonic solution. What will happen to the cell?

Accepted Answer

It will become flaccid due to lack of net water movement.

The Working Cell: Membrane Structure, Transport, and Enzymes

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