Question 1

Which of the following best describes the main difference between prokaryotic and eukaryotic cells?

Accepted Answer

Eukaryotic cells have their DNA enclosed within a nucleus, whereas prokaryotic cells have their DNA in a nucleoid region.

Question 2

A scientist observes a cell under an electron microscope and notes the presence of a large central vacuole, chloroplasts, and a cell wall. Which type of cell is being observed?

Accepted Answer

Plant cell

Question 3

Which of the following statements about free and bound ribosomes is correct?

Accepted Answer

Bound ribosomes are attached to the endoplasmic reticulum and synthesize proteins for membranes or secretion.

Question 4

The 9+2 arrangement of microtubules is characteristic of which cellular structures?

Accepted Answer

Cilia and flagella

Question 5

Which component of the extracellular matrix (ECM) is primarily responsible for providing tensile strength to animal tissues?

Accepted Answer

Collagen fibers

Question 6

Which type of cell junction prevents the leakage of extracellular fluid across a layer of epithelial cells?

Accepted Answer

Tight junctions

Question 7

According to the Fluid Mosaic Model, which statement best describes the structure of the plasma membrane?

Accepted Answer

A dynamic bilayer of phospholipids with proteins and other molecules embedded and able to move laterally.

Question 8

How does the presence of unsaturated fatty acids in phospholipids affect the fluidity of the cell membrane?

Accepted Answer

It increases membrane fluidity by preventing tight packing of phospholipids.

Question 9

Which of the following substances can cross the plasma membrane without the aid of transport proteins?

Accepted Answer

Small nonpolar molecules such as $$\mathrm{O_2$}$$ and $$\mathrm{CO_2$}$$

Question 10

An animal cell is placed in a hypotonic solution. What is the most likely outcome?

Accepted Answer

The cell will gain water and may burst (lyse).

Question 11

Which of the following best describes the function of the sodium-potassium pump?

Accepted Answer

It uses ATP to move $$\mathrm{Na^+}$$ out of the cell and $$\mathrm{K^+}$$ into the cell against their concentration gradients.

Question 12

Which of the following is an example of an exergonic (catabolic) reaction in human metabolism?

Accepted Answer

Breakdown of glucose during cellular respiration

Question 13

Which law of thermodynamics explains why no energy transformation is 100% efficient and some energy is always lost as heat?

Accepted Answer

Second law of thermodynamics

Question 14

What is the primary function of ATP in cellular metabolism?

Accepted Answer

To provide energy for cellular work by transferring a phosphate group

Question 15

A process is considered spontaneous if which of the following is true?

Accepted Answer

It decreases the free energy ($$\Delta G \u003c 0) of $$the system.

Question 16

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

Accepted Answer

A muscle contracting to move a limb

Question 17

An enzyme-catalyzed reaction is observed to slow down dramatically when the pH is changed from 7 to 3. What is the most likely explanation?

Accepted Answer

The enzyme is denatured at low pH, altering its active site.

Question 18

Which of the following best describes competitive inhibition of an enzyme?

Accepted Answer

An inhibitor binds to the active site, preventing substrate binding.

Question 19

What is activation energy, and how do enzymes affect it?

Accepted Answer

Activation energy is the energy needed to start a reaction; enzymes lower the activation energy.

Question 20

A metabolic pathway is regulated by feedback inhibition. Which of the following best describes this process?

Accepted Answer

The final product of the pathway binds to an allosteric site on an early enzyme, decreasing its activity.

General Biology Exam 2 Study Guide: Step-by-Step Guidance

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