Question 1

Which component of the extracellular matrix (ECM) in animal cells is primarily responsible for providing structural support and resisting tension?

Accepted Answer

Collagen

Question 2

In plant cells, what is the main function of the primary cell wall?

Accepted Answer

Defines cell shape and counteracts turgor pressure

Question 3

Which structure connects adjacent plant cells and allows the flow of cytoplasm, forming the symplast?

Accepted Answer

Plasmodesmata

Question 4

What is the role of integrins in animal cells?

Accepted Answer

They anchor the cytoskeleton to the extracellular matrix

Question 5

Which of the following best describes the function of tight junctions in animal cells?

Accepted Answer

They form a watertight seal between adjacent cells

Question 6

Cadherins are most directly involved in which type of cell–cell attachment?

Accepted Answer

Desmosomes

Question 7

Which equation best represents the conversion of GTP to GDP in G-protein signaling?

Accepted Answer

$$\mathrm{GTP} \rightarrow \mathrm{GDP} + \mathrm{P_i}$$

Question 8

Which signaling pathway is most likely to amplify and diversify a signal through the production of second messengers?

Accepted Answer

G-protein-coupled receptor pathway

Question 9

A mutation prevents the phosphorylation of receptor tyrosine kinases (RTKs). Which cellular process would be most directly affected?

Accepted Answer

Initiation of a phosphorylation cascade

Question 10

Which of the following is NOT a method of signal transduction?

Accepted Answer

Lipid-soluble signaling molecules binding intracellular receptors and directly participating in intracellular activities

Question 11

Which of the following best describes the process of quorum sensing in bacteria?

Accepted Answer

Bacteria release species-specific signaling molecules when population density reaches a threshold

Question 12

What is the ultimate cellular response to a signaling molecule binding its receptor?

Accepted Answer

Change in gene expression or activity of existing proteins

Question 13

Which mechanism allows cells to remain sensitive to small changes in signaling by rapidly turning off intracellular signals?

Accepted Answer

Phosphatases removing phosphate groups from proteins

Question 14

Which equation represents the osmotic movement of water into a plant cell, resulting in turgor pressure?

Accepted Answer

$$\Psi_{total} = \Psi_{pressure} + \Psi_{solute}$$

Question 15

Which of the following best explains why only cells with appropriate signal receptors respond to a particular signaling molecule?

Accepted Answer

Receptors are specific to the signaling molecule's shape and chemistry

Question 16

Which of the following is a real-world example of crosstalk between signaling pathways?

Accepted Answer

A hormone pathway inhibiting a second pathway, reducing the cell’s response to the second signal

Question 17

Which protein is responsible for the rubber-like consistency of cartilage in animal tissues?

Accepted Answer

Proteoglycans

Question 18

What is the main difference between the cell wall of bacteria and archaea?

Accepted Answer

Bacteria have peptidoglycan, archaea have a dense coat of proteins (S-layer)

Question 19

Which of the following best describes the function of expansins in young, growing plant cells?

Accepted Answer

They disrupt cross-linking between cellulose microfibrils, allowing cell growth

Question 20

Which of the following is a plausible consequence of blocking signal receptors with beta-blocker drugs?

Accepted Answer

Cells become less sensitive to hormone signals

Cell–Cell Interactions: Structure, Communication, and Signaling

Study Guide - Practice Questions