Question 1

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

Accepted Answer

A dynamic structure where proteins float in or on a flexible bilayer of phospholipids.

Question 2

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

Accepted Answer

The cell will swell and possibly burst because water will move into the cell.

Question 3

Which of the following substances can diffuse directly through the plasma membrane without the aid of a transport protein?

Accepted Answer

Oxygen ($$O_2)$$

Question 4

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

Accepted Answer

It moves $$3$$ $$Na^+$$ ions out of the cell and $$2$$ $$K^+$$ ions into the cell using ATP.

Question 5

A cell is exposed to a toxin that inhibits G protein-coupled receptor (GPCR) signaling. Which process would be most directly affected?

Accepted Answer

Hormone-induced activation of adenylate cyclase

Question 6

Which of the following is a correct sequence of events in receptor-mediated endocytosis?

Accepted Answer

Ligand binds receptor → vesicle forms → vesicle fuses with lysosome → contents released

Question 7

Which enzyme is responsible for unwinding the DNA double helix during DNA replication?

Accepted Answer

Helicase

Question 8

During transcription, which of the following best describes the base pairing rules between DNA and mRNA?

Accepted Answer

$$A$$ pairs with $$U$$, $$T$$ pairs with $$A$$, $$C$$ pairs with $$G$$, $$G$$ pairs with $$C$$

Question 9

Which of the following best explains the concept of genetic code redundancy?

Accepted Answer

Some amino acids are coded by more than one codon.

Question 10

A mutation changes a DNA base from $$A to$$ $$G in a $$gene, but the resulting protein is unchanged. What is the most likely explanation?

Accepted Answer

The genetic code is redundant, so the new codon still codes for the same amino acid.

Question 11

Which of the following is NOT a function of lysosomes?

Accepted Answer

Synthesizing proteins

Question 12

Which type of cell junction allows ions and small molecules to pass directly from one cell to another, as seen in cardiac muscle?

Accepted Answer

Gap junction

Question 13

Which of the following best describes the role of the signal recognition particle (SRP) in protein synthesis?

Accepted Answer

It directs ribosomes to the rough endoplasmic reticulum for protein targeting.

Question 14

Which germ layer gives rise to the epithelial lining of the digestive tract?

Accepted Answer

Endoderm

Question 15

Which of the following is a characteristic of connective tissue, but NOT epithelial tissue?

Accepted Answer

Cells are widely spaced and embedded in abundant extracellular matrix.

Question 16

A patient with a genetic defect in collagen synthesis would most likely have problems with which tissue type?

Accepted Answer

Connective tissue

Question 17

Which of the following best describes the process of secondary active transport?

Accepted Answer

Movement of one molecule against its gradient, coupled to the movement of another molecule down its gradient.

Question 18

Which type of epithelial tissue is best adapted for rapid diffusion and is found lining the air sacs of the lungs?

Accepted Answer

Simple squamous epithelium

Question 19

During inflammation, which stage is characterized by the movement of white blood cells out of the bloodstream to the site of injury?

Accepted Answer

Diapedesis

Question 20

Which of the following best describes the organization of DNA in the nucleus during interphase?

Accepted Answer

DNA is loosely coiled as chromatin, allowing access for transcription.

Comprehensive Study Notes: Cell Structure, Genetics, and Tissue Organization in Anatomy & Physiology

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