Question 1

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

Accepted Answer

A double layer of phospholipids with embedded proteins that move and shift, with carbohydrates on the surface.

Question 2

A patient receives an intravenous solution that is hypertonic relative to their red blood cells. What is the most likely effect on the cells?

Accepted Answer

The cells will shrink as water leaves the cell, a process called crenation.

Question 3

Which of the following is a function of the glycocalyx on the cell surface?

Accepted Answer

Serving as a biological marker for cell-to-cell recognition.

Question 4

Which type of membrane protein is primarily responsible for catalyzing sequential steps in a metabolic pathway?

Accepted Answer

Enzymatic proteins

Question 5

A mutation causes the sodium-potassium pump to stop functioning. What immediate effect would this have on a neuron’s resting membrane potential?

Accepted Answer

The resting membrane potential would become more positive as sodium accumulates inside the cell.

Question 6

Which of the following best explains why oxygen can diffuse directly through the plasma membrane, but glucose cannot?

Accepted Answer

Oxygen is nonpolar and lipid-soluble, while glucose is polar and requires a carrier protein.

Question 7

Which organelle is responsible for synthesizing steroid-based hormones and detoxifying drugs in the liver?

Accepted Answer

Smooth endoplasmic reticulum

Question 8

A genetic disorder prevents the formation of lysosomal enzymes needed to break down glycolipids in nerve cells. Which disease does this describe, and what is a key symptom?

Accepted Answer

Tay-Sachs disease; progressive loss of developmental milestones and a 'cherry red spot' on the retina.

Question 9

Which of the following best describes the process of receptor-mediated endocytosis?

Accepted Answer

Selective uptake of specific molecules bound to receptors on the cell surface.

Question 10

Which cytoskeletal element is primarily responsible for resisting pulling forces and is composed of tetramer fibrils twisted together?

Accepted Answer

Intermediate filaments

Question 11

A cell is placed in a solution and begins to swell until it bursts. Which of the following best describes the tonicity of the solution and the process occurring?

Accepted Answer

The solution is hypotonic; water is entering the cell by osmosis.

Question 12

Which of the following is a direct result of the action of G protein–coupled receptors?

Accepted Answer

Activation of intracellular second messengers such as cyclic AMP.

Question 13

Which of the following best explains why mitochondria are considered the 'power plants' of the cell?

Accepted Answer

They produce most of the cell’s ATP via aerobic respiration.

Question 14

During which phase of the cell cycle does DNA replication occur, and what is the significance of this process?

Accepted Answer

S phase; it ensures each daughter cell receives an identical set of genetic information.

Question 15

Which of the following is true regarding the process of translation in protein synthesis?

Accepted Answer

It occurs in the cytoplasm and involves decoding mRNA to assemble a polypeptide chain.

Question 16

Which of the following best describes the role of telomerase in cell division and aging?

Accepted Answer

It lengthens telomeres, allowing cells such as cancer cells to divide indefinitely.

Question 17

Which of the following is a real-life example of secondary active transport in the human body?

Accepted Answer

Glucose absorption in the small intestine, where sodium moving down its gradient drives glucose uptake against its gradient.

Question 18

Which of the following best describes the function of microvilli on intestinal epithelial cells?

Accepted Answer

To increase surface area for absorption of nutrients.

Question 19

Which of the following is a key difference between simple diffusion and facilitated diffusion across the plasma membrane?

Accepted Answer

Facilitated diffusion requires membrane proteins to transport polar or large molecules.

Question 20

A cell is exposed to a toxin that prevents the formation of spindle fibers. Which stage of mitosis would be directly affected, and what would be the consequence?

Accepted Answer

Metaphase; chromosomes would not align at the metaphase plate.

Cells: The Living Units – Structure, Function, and Membrane Dynamics

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