Question 1

Which type of cell junction is primarily responsible for preventing the passage of substances between adjacent epithelial cells, such as those lining the intestines?

Accepted Answer

Tight junctions

Question 2

A patient with a genetic defect in desmosomal proteins is most likely to experience which of the following symptoms?

Accepted Answer

Weakness and blistering of the skin under mechanical stress

Question 3

Which component of the extracellular matrix (ECM) is most directly responsible for providing tensile strength to tissues such as tendons?

Accepted Answer

Collagen

Question 4

During wound healing, cells must temporarily attach and detach from each other as they migrate to close the wound. Which type of cell–cell adhesion is most involved in this process?

Accepted Answer

Transient cell–cell adhesions

Question 5

Gap junctions are essential for the synchronized contraction of heart muscle cells. Which of the following best explains their function?

Accepted Answer

They create channels allowing ions and small molecules to pass directly between cells.

Question 6

A mutation in integrin proteins would most likely disrupt which of the following cellular processes?

Accepted Answer

Anchoring of cells to the extracellular matrix and cell signaling

Question 7

Which ECM component is most important for resisting compressive forces and retaining water in cartilage tissue?

Accepted Answer

Proteoglycans

Question 8

A researcher is studying a tissue that must stretch and return to its original shape, such as lung tissue. Which ECM protein should she focus on?

Accepted Answer

Elastin

Question 9

Which of the following best describes the role of fibronectin in the extracellular matrix?

Accepted Answer

It connects cells to collagen fibers, aiding in cell movement.

Question 10

A scientist observes that certain cells in culture are unable to migrate properly during development. Which ECM component is most likely deficient?

Accepted Answer

Hyaluronate

Question 11

Which of the following best explains why the blood-brain barrier is highly selective in what it allows to pass between the bloodstream and brain tissue?

Accepted Answer

Abundance of tight junctions sealing adjacent cells

Question 12

Which of the following is a key difference between adherens junctions and desmosomes?

Accepted Answer

Adherens junctions connect actin filaments, while desmosomes connect intermediate filaments.

Question 13

A tissue sample is found to have a deficiency in laminin. Which of the following consequences is most likely?

Accepted Answer

Cells are unable to anchor to the basal lamina.

Question 14

Which of the following best describes the function of integrins in animal cells?

Accepted Answer

They connect the extracellular matrix to the cytoskeleton and participate in signaling.

Question 15

A patient with a mutation in a gene encoding a proteoglycan is most likely to have which of the following symptoms?

Accepted Answer

Reduced ability to resist compressive forces in cartilage

Question 16

Which of the following scenarios best illustrates the importance of adhesive glycoproteins in the ECM?

Accepted Answer

A wound healing process where cells migrate across a collagen-rich matrix

Question 17

If a mutation caused a loss of function in gap junction proteins in cardiac muscle, which of the following would most likely occur?

Accepted Answer

Heart muscle cells would be unable to contract in a coordinated manner.

Question 18

Which of the following best explains why the ECM is considered dynamic rather than just a static support structure?

Accepted Answer

It influences cell behavior, signaling, and guides cell movement.

Question 19

A scientist is studying a disease in which cells cannot properly attach to collagen fibers in the ECM. Which protein is most likely defective?

Accepted Answer

Fibronectin

Question 20

Which of the following best describes the relationship between integrins and the cytoskeleton?

Accepted Answer

Integrins connect the ECM outside the cell to the cytoskeleton inside the cell.

Cell–Cell Junctions and the Extracellular Matrix in Animal Cells

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