Question 1

Which of the following best describes the primary structural role of collagen in the extracellular matrix (ECM) of animal cells?

Accepted Answer

To provide rigidity and tensile strength to tissues

Question 2

A patient presents with skin that is less elastic and more prone to scarring as they age. Which ECM component is most likely affected?

Accepted Answer

Elastin

Question 3

Which of the following is a correct description of a proteoglycan?

Accepted Answer

A core protein with glycosaminoglycans (GAGs) attached

Question 4

Which of the following best explains why cancer cells can grow in soft agar, while normal cells cannot?

Accepted Answer

Cancer cells exhibit anchorage-independent growth due to constitutive activation of growth pathways

Question 5

Which of the following is the main function of integrins in animal cells?

Accepted Answer

To connect the cytoskeleton to the ECM and mediate signal transduction

Question 6

A mutation in the gene encoding claudin would most likely disrupt which cellular structure and function?

Accepted Answer

Tight junctions; permeability barrier and cell polarity

Question 7

Which of the following best describes the role of fibronectin in the ECM?

Accepted Answer

To serve as a bridge connecting cells to the rest of the ECM

Question 8

Which of the following statements about gap junctions is correct?

Accepted Answer

They are composed of connexins that form connexons

Question 9

A researcher injects a fluorescent dye with a molecular weight of 1200 Da into one cell. The dye passes to neighboring cells, but a dye of 2000 Da does not. Which structure is responsible for this selective passage?

Accepted Answer

Gap junctions

Question 10

Which of the following best explains why elevated intracellular $$\mathrm{Ca$$^{2+}$$}$$ closes gap junctions?

Accepted Answer

To prevent the spread of cell death signals to neighboring cells

Question 11

Which of the following is a correct pairing of a pathogen and the cell adhesion protein it exploits to enter host cells?

Accepted Answer

Yersinia – Integrin

Question 12

Which of the following best describes the difference between lamin and laminin?

Accepted Answer

Lamin is an intermediate filament under the nuclear membrane; laminin is a glycoprotein in the ECM

Question 13

Which of the following cell junctions is primarily responsible for maintaining the polarity of epithelial cells?

Accepted Answer

Tight junctions

Question 14

Which of the following best describes a homophilic interaction in cell-cell adhesion?

Accepted Answer

Interaction between identical adhesion proteins on neighboring cells

Question 15

Which of the following ECM components is most responsible for holding water and hydrating tissues?

Accepted Answer

Proteoglycans

Question 16

Which of the following best explains why tight junctions are critical in the blood-brain barrier (BBB)?

Accepted Answer

They prevent lateral diffusion of membrane proteins and block paracellular transport

Question 17

Which of the following is a real-life application of integrin function in medicine?

Accepted Answer

Blocking integrin activity can reduce cancer metastasis by preventing cell migration

Question 18

Which of the following best describes the function of gap junctions in cardiac muscle tissue?

Accepted Answer

They allow rapid passage of ions for synchronized contraction

Question 19

Plasmodesmata in plant cells are most similar in function to which structure in animal cells?

Accepted Answer

Gap junctions

Question 20

Which of the following best explains the role of integrin clustering in normal cell growth?

Accepted Answer

Integrin clustering activates growth pathways, allowing anchorage-dependent growth

Extracellular Matrix and Cell Junctions in Animal Cells

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