Question 1

Which of the following best describes why the phospholipid bilayer of cell membranes is fluid rather than solid at physiological temperatures?

Accepted Answer

The presence of cholesterol and unsaturated fatty acids prevents tight packing of phospholipids.

Question 2

A red blood cell is placed in a hypertonic solution. What will most likely happen to the cell, and why?

Accepted Answer

It will shrink because water will move out of the cell to the area of higher solute concentration.

Question 3

Which of the following equations correctly represents the relationship between pH and hydrogen ion concentration $$[H^+]$$?

Accepted Answer

$$pH = -\log_{10} [H^+]$$

Question 4

During cellular respiration, which molecule acts as the final electron acceptor in the electron transport chain, and why is this important?

Accepted Answer

Oxygen, because it has a high electronegativity and allows for efficient ATP production.

Question 5

Which of the following best explains why enzymes become less efficient at temperatures above their optimal range?

Accepted Answer

High temperatures can denature the enzyme, altering the shape of its active site.

Question 6

Which of the following statements about the Laws of Thermodynamics as they apply to living organisms is correct?

Accepted Answer

The first law states that energy cannot be created or destroyed, only transformed.

Question 7

In the context of photosynthesis, which molecule is oxidized and which is reduced in the overall reaction: $$6CO_2 + 6H_2O + 	ext{Light Energy} ightarrow C_6H_{12}O_6$ + 6O_2$$?

Accepted Answer

Water is oxidized and carbon dioxide is reduced.

Question 8

Which of the following best describes substrate-level phosphorylation?

Accepted Answer

The direct transfer of a phosphate group from a substrate to ADP to form ATP.

Question 9

A scientist adds more substrate to an enzyme-catalyzed reaction, but the reaction rate does not increase. What is the most likely explanation?

Accepted Answer

All enzyme active sites are saturated with substrate.

Question 10

Which of the following best explains why ATP is able to store and transfer energy within the cell?

Accepted Answer

ATP contains high-energy phosphate bonds that release energy when hydrolyzed.

Question 11

Which of the following is a correct statement about the function of cholesterol in animal cell membranes?

Accepted Answer

At human body temperature, cholesterol reduces membrane fluidity by restricting phospholipid movement.

Question 12

During aerobic respiration, which step produces the most ATP per glucose molecule?

Accepted Answer

Oxidative phosphorylation

Question 13

Which of the following best describes the difference between competitive and noncompetitive enzyme inhibitors?

Accepted Answer

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

Question 14

Which of the following is a real-world example of an exergonic reaction in living organisms?

Accepted Answer

The breakdown of glucose during cellular respiration.

Question 15

Which of the following best explains why oxygen is required for aerobic respiration?

Accepted Answer

Oxygen acts as the final electron acceptor in the electron transport chain, allowing for the production of water and ATP.

Question 16

Which of the following best describes the main function of light-harvesting complexes in photosynthesis?

Accepted Answer

They capture and transfer light energy to the reaction center chlorophyll.

Question 17

If a plant's leaves appear green, what does this indicate about the wavelengths of light being absorbed and reflected?

Accepted Answer

Green wavelengths are being reflected, while red and blue wavelengths are being absorbed.

Question 18

Which of the following best describes the process of chemiosmosis in cellular respiration?

Accepted Answer

The movement of protons down their concentration gradient through ATP synthase to produce ATP.

Question 19

Which of the following is a product of lactic acid fermentation in human muscle cells?

Accepted Answer

ATP and lactic acid

Question 20

Which of the following best explains why low temperature organisms have membranes with a high ratio of unsaturated fatty acids?

Accepted Answer

Unsaturated fatty acids prevent the membrane from solidifying at low temperatures.

General Biology Exam 2 Review: Cell Structure, Metabolism, Respiration, and Photosynthesis

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