Question 1

Which of the following best describes the function of the rough endoplasmic reticulum (RER) in a eukaryotic cell?

Accepted Answer

It is involved in the synthesis and initial folding of proteins destined for secretion or membrane insertion.

Question 2

A patient is given a drug that blocks voltage-gated sodium channels in neurons. What is the most likely effect on neuronal function?

Accepted Answer

The neuron will be unable to initiate or propagate action potentials.

Question 3

Which of the following best explains why steroid hormones can pass through the plasma membrane, while peptide hormones cannot?

Accepted Answer

Steroid hormones are lipophilic and can diffuse through the lipid bilayer, while peptide hormones are hydrophilic and require membrane receptors.

Question 4

Which of the following is the correct complementary base pairing in DNA?

Accepted Answer

Adenine pairs with thymine, guanine pairs with cytosine

Question 5

A solution contains $\mathrm{Na^+}$ ions. If the atomic number of sodium is 11 and the mass number is 23, how many electrons does a $\mathrm{Na^+}$ ion have?

Accepted Answer

10

Question 6

Which of the following best describes secondary active transport?

Accepted Answer

It uses the energy from the movement of one molecule down its gradient to move another molecule against its gradient.

Question 7

During the process of transcription, which molecule is synthesized from a DNA template?

Accepted Answer

mRNA

Question 8

Which of the following best describes the difference between passive and active transport across a cell membrane?

Accepted Answer

Passive transport moves molecules down their concentration gradient without energy input, while active transport requires energy to move molecules against their gradient.

Question 9

A ligand-gated ion channel opens in response to the binding of a neurotransmitter. What is the immediate result?

Accepted Answer

Ions flow across the membrane, changing the membrane potential.

Question 10

Which of the following molecules is most likely to form ionic bonds?

Accepted Answer

A metal and a nonmetal with a large difference in electronegativity

Question 11

A cell is placed in a hypertonic solution. Predict the movement of water and the likely outcome for the cell.

Accepted Answer

Water will move out of the cell, causing it to shrink (crenate).

Question 12

Which of the following best describes a 'leak channel' in a cell membrane?

Accepted Answer

A channel that is always open, allowing ions to move down their concentration gradient.

Question 13

Which of the following is an example of a negative feedback mechanism in the human body?

Accepted Answer

Regulation of blood glucose by insulin lowering blood sugar after a meal.

Question 14

Given the following chemical reaction: $\mathrm{C_6H_{12}O_6} + 6\ \mathrm{O_2} \rightarrow 6\ \mathrm{CO_2} + 6\ \mathrm{H_2O}$, which law does this reaction illustrate?

Accepted Answer

Law of Conservation of Mass

Question 15

Which of the following best describes the role of cAMP in cell signaling?

Accepted Answer

It is a secondary messenger that activates protein kinases inside the cell.

Question 16

A mutation causes a channel protein to remain permanently open. What is the most likely effect on the cell's membrane potential?

Accepted Answer

The membrane potential will move toward the equilibrium potential of the ion passing through the channel.

Question 17

Which of the following best describes the difference between a fast ligand-gated channel and a slow ligand-gated channel?

Accepted Answer

Fast channels directly open in response to ligand binding, while slow channels involve second messengers and intracellular signaling cascades.

Question 18

Which of the following best explains why the rate of diffusion increases with increasing temperature?

Accepted Answer

Higher temperature increases the kinetic energy of molecules, causing them to move faster.

Question 19

Which of the following is true regarding the sodium-potassium pump ($\mathrm{Na^+/K^+}$-ATPase)?

Accepted Answer

It moves 3 $\mathrm{Na^+}$ ions out of the cell and 2 $\mathrm{K^+}$ ions into the cell per ATP hydrolyzed.

BIO1521 Anatomy & Physiology Exam Study Guide: Cellular and Molecular Foundations

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