Question 1

Which of the following best describes the fluid mosaic model of the plasma membrane?

Accepted Answer

A dynamic, flexible structure where proteins float in or on a fluid lipid bilayer, allowing lateral movement.

Question 2

A red blood cell is placed in a solution and begins to swell and eventually bursts. Which type of solution was the cell placed in, and what is the underlying mechanism?

Accepted Answer

Hypotonic; water moves into the cell because the extracellular fluid has a lower solute concentration.

Question 3

Which of the following is NOT a function of the glycocalyx?

Accepted Answer

Acting as a selective channel for ion transport.

Question 4

Which of the following best describes the difference between primary and secondary active transport?

Accepted Answer

Primary active transport directly uses ATP, while secondary active transport uses the energy stored in ion gradients created by primary active transport.

Question 5

Which of the following equations correctly represents osmotic pressure ($$\Pi) $$according to van't Hoff's law?

Accepted Answer

$$\Pi = iMRT$$

Question 6

A patient is given an intravenous solution with an osmolarity significantly higher than their blood plasma. What is the most likely effect on their red blood cells?

Accepted Answer

Cells will shrink (crenate) as water leaves the cell.

Question 7

Which of the following best describes the function of tight junctions in epithelial tissue?

Accepted Answer

They prevent the passage of substances between adjacent cells, maintaining distinct compartments.

Question 8

Which of the following is a correct sequence of events for DNA replication?

Accepted Answer

Unwinding of DNA, pairing of new nucleotides, joining of Okazaki fragments, formation of two identical DNA molecules.

Question 9

Which of the following best explains why the sodium/potassium pump is essential for maintaining the resting membrane potential?

Accepted Answer

It actively transports 3 sodium ions out and 2 potassium ions into the cell, creating an electrochemical gradient.

Question 10

Which of the following is a key difference between antiporters and symporters?

Accepted Answer

Antiporters move two substances in opposite directions across the membrane, while symporters move them in the same direction.

Question 11

Which of the following best describes the process of exocytosis?

Accepted Answer

The cell releases substances to the extracellular space by fusing vesicles with the plasma membrane.

Question 12

Which of the following is NOT a membranous organelle?

Accepted Answer

Ribosome

Question 13

During which phase of the cell cycle does DNA replication occur?

Accepted Answer

S phase

Question 14

Which of the following best describes semiconservative replication?

Accepted Answer

Each new DNA molecule consists of one original strand and one newly synthesized strand.

Question 15

Which of the following statements about gap junctions is correct?

Accepted Answer

They allow direct communication between adjacent cells by permitting the passage of ions and small molecules.

Question 16

Which of the following best describes the role of cyclins and cyclin-dependent kinases (Cdks) in the cell cycle?

Accepted Answer

Cyclins and Cdks form complexes that regulate progression through the cell cycle by phosphorylating target proteins.

Question 17

Which of the following is the correct sequence of events in mRNA translation?

Accepted Answer

Initiation, elongation, termination

Question 18

Which of the following best describes apoptosis?

Accepted Answer

A process where cells self-destruct in a controlled manner, playing a role in development and disease prevention.

Question 19

Which of the following best describes the function of plasma membrane receptors?

Accepted Answer

They detect chemical signals from the extracellular environment and initiate cellular responses.

Question 20

Which of the following is a function of cell adhesion molecules (CAMs)?

Accepted Answer

Facilitating cell movement and binding cells together during tissue formation.

Chapter 3 Cell Biology Study Guide – Step-by-Step Guidance

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