Question 1

Which of the following best describes the fluid mosaic model of cell membranes?

Accepted Answer

A flexible bilayer of phospholipids with proteins and other molecules drifting laterally within it.

Question 2

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

Accepted Answer

Synthesizing phospholipids from fatty acids.

Question 3

How does the amphipathic nature of phospholipids contribute to the structure of cell membranes?

Accepted Answer

It causes phospholipids to form a bilayer with hydrophobic tails facing inward and hydrophilic heads facing outward.

Question 4

Which equation best represents the process of passive transport by diffusion?

Accepted Answer

$$ J = -D \frac{dC}{dx} $$

Question 5

Osmosis is best defined as:

Accepted Answer

The movement of water molecules across a selectively permeable membrane from low solute concentration to high solute concentration.

Question 6

A red blood cell placed in a hypertonic solution will:

Accepted Answer

Shrink as water leaves the cell.

Question 7

Which of the following best explains how transport proteins facilitate diffusion?

Accepted Answer

They provide a hydrophilic channel for specific molecules to passively move down their concentration gradient.

Question 8

Which process involves the engulfment of large particles by the cell membrane?

Accepted Answer

Phagocytosis

Question 9

Which of the following is an example of potential energy in a biological system?

Accepted Answer

The chemical bonds in a molecule of glucose.

Question 10

Which statement best summarizes the first law of thermodynamics as it applies to biological systems?

Accepted Answer

Energy cannot be created or destroyed, only transformed from one form to another.

Question 11

Which reaction is endergonic?

Accepted Answer

Photosynthesis

Question 12

How does ATP function as an energy shuttle in cells?

Accepted Answer

By storing energy in its phosphate bonds and releasing it when hydrolyzed to ADP.

Question 13

Which of the following best explains how enzymes speed up chemical reactions?

Accepted Answer

By lowering the activation energy required for the reaction.

Question 14

A competitive inhibitor affects an enzyme by:

Accepted Answer

Binding to the active site and blocking substrate binding.

Question 15

Which of the following is a possible effect of a pesticide acting as a noncompetitive inhibitor?

Accepted Answer

It binds to a site other than the active site, altering enzyme function.

Question 16

Which equation represents the overall chemical reaction for cellular respiration?

Accepted Answer

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

Question 17

During which stage of cellular respiration is the majority of ATP produced?

Accepted Answer

Electron transport chain and oxidative phosphorylation

Question 18

Which of the following best describes the role of NADH in cellular respiration?

Accepted Answer

It donates electrons to the electron transport chain.

Question 19

Which of the following statements about brown fat is correct?

Accepted Answer

Brown fat generates heat by uncoupling electron transport from ATP synthesis.

Question 20

Which process yields more ATP per glucose molecule: aerobic respiration or fermentation? Why?

Accepted Answer

Aerobic respiration, because it uses oxygen as the final electron acceptor in the electron transport chain.

Key Concepts in Cell Membranes, Energy, Enzymes, and Cellular Respiration

Study Guide - Practice Questions