Q: A cell uses the sodium-potassium pump to maintain ion gradients. For each cycle, how many sodium ions are pumped out and how many potassium ions are pumped in?

$$3$$ \text{ Na}^+$$ out, 2$ \text{ K}^+ in$$

Question 1

Which of the following best explains why phospholipids form bilayers in cellular membranes?

Accepted Answer

Phospholipids have both hydrophilic and hydrophobic regions, causing them to arrange with hydrophilic heads facing water and hydrophobic tails facing inward.

Question 2

A red blood cell is placed in a solution and swells until it bursts. Which type of solution is the cell in?

Accepted Answer

Hypotonic solution

Question 3

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

Accepted Answer

Membrane proteins and lipids can move laterally within the bilayer, contributing to membrane fluidity.

Question 4

Which process requires energy input from the cell and moves molecules against their concentration gradient?

Accepted Answer

Active transport

Question 5

A cell uses the sodium-potassium pump to maintain ion gradients. For each cycle, how many sodium ions are pumped out and how many potassium ions are pumped in?

Accepted Answer

$$3$$ 	ext{ Na}^+$$ out, 2$ 	ext{ K}^+ in$$

Question 6

Which of the following is a function of membrane proteins?

Accepted Answer

Transporting specific molecules across the membrane

Question 7

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

Accepted Answer

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

Question 8

Which of the following best describes an exergonic reaction?

Accepted Answer

A reaction that releases free energy and has a negative $$\Delta G$$

Question 9

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

Accepted Answer

Oxygen ($$	ext{O}_2)$$

Question 10

Which of the following statements about enzymes is correct?

Accepted Answer

Enzymes lower the activation energy, speeding up the reaction.

Question 11

A competitive inhibitor affects enzyme activity by:

Accepted Answer

Binding to the active site and blocking substrate binding.

Question 12

Which of the following is true about facilitated diffusion?

Accepted Answer

It uses transport proteins to move molecules down their concentration gradient.

Question 13

Which process is responsible for the movement of water across a selectively permeable membrane?

Accepted Answer

Osmosis

Question 14

Which of the following would increase membrane fluidity at lower temperatures?

Accepted Answer

Increasing the proportion of unsaturated fatty acids in phospholipids

Question 15

Which of the following is a real-life example of bulk transport in cells?

Accepted Answer

Secretion of insulin by pancreatic cells via exocytosis

Question 16

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

Accepted Answer

NAD+ functions as an electron carrier, accepting electrons during redox reactions.

Question 17

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

Accepted Answer

Transporting ions across the membrane

Question 18

Which of the following would most likely occur if a cell's ATP production suddenly stopped?

Accepted Answer

Active transport across the membrane would decrease.

Question 19

Which of the following best describes the difference between substrate-level phosphorylation and oxidative phosphorylation?

Accepted Answer

Substrate-level phosphorylation directly transfers a phosphate group to ADP from a substrate, while oxidative phosphorylation uses the electron transport chain and chemiosmosis to generate ATP.

Cell Membranes, Metabolism, and Cellular Processes: Study Notes for General Biology

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