Question 1

Which of the following best describes the role of cadherins in cell-cell adhesion?

Accepted Answer

They form homophilic interactions that are calcium-dependent, linking adjacent cells together.

Question 2

What is the primary function of catenins in adherens junctions?

Accepted Answer

To link cadherins to actin filaments, facilitating mechanotransduction.

Question 3

Which of the following statements about the 'Velcro principle' in cell adhesion is correct?

Accepted Answer

It refers to the low-affinity but high-avidity binding of multiple cadherin molecules between cells.

Question 4

A mutation that prevents calcium binding to cadherins would most likely result in which of the following?

Accepted Answer

Loss of cell-cell adhesion due to increased flexibility of cadherin molecules.

Question 5

Which protein links desmosomal cadherins to intermediate filaments in desmosomes?

Accepted Answer

Desmoplakin

Question 6

Which of the following best explains the function of tight junctions in epithelial tissues?

Accepted Answer

They create a selective barrier that regulates paracellular transport between cells.

Question 7

Gap junctions allow the passage of molecules up to what approximate size?

Accepted Answer

$$\approx 1000 to$$ $$5000$$ daltons

Question 8

Which of the following is a key component of the basal lamina that interacts with integrins?

Accepted Answer

Laminin

Question 9

A cell loses contact with the extracellular matrix (ECM). What is the most likely cellular response?

Accepted Answer

The cell undergoes apoptosis due to loss of anchorage dependence.

Question 10

Which signaling pathway is most directly involved in activating integrins from inside the cell?

Accepted Answer

Inside-out signaling involving talin and kindlin binding to integrin cytoplasmic domains.

Question 11

Which of the following best describes the role of matrix metalloproteases in cell migration?

Accepted Answer

They degrade components of the basal lamina, allowing cells to migrate through the ECM.

Question 12

Which of the following is a glycoprotein found in the ECM that helps organize the basal lamina?

Accepted Answer

Nidogen

Question 13

Which cytoskeletal element is linked to cadherins in adherens junctions?

Accepted Answer

Actin filaments

Question 14

Which of the following best describes the difference between adherens junctions and desmosomes?

Accepted Answer

Adherens junctions link to actin filaments, while desmosomes link to intermediate filaments.

Question 15

Which of the following ECM components is classified as a proteoglycan?

Accepted Answer

Aggrecan

Question 16

Which process is most directly affected by the activity of Rho GTPase in epithelial cells?

Accepted Answer

Formation of actin-myosin stress fibers and increased cortical tension

Question 17

Which of the following best explains the function of hemidesmosomes?

Accepted Answer

They anchor epithelial cells to the basal lamina via integrins and intermediate filaments.

Question 18

Which ECM protein is most important for providing tensile strength to tissues?

Accepted Answer

Collagen

Question 19

A researcher observes that cells lacking vinculin fail to respond to mechanical tension at adherens junctions. What is the most likely explanation?

Accepted Answer

Vinculin is required for linking actin filaments to the cadherin-catenin complex under tension.

Question 20

Which of the following best describes the process of mechanotransduction at adherens junctions?

Accepted Answer

Mechanical stress on cadherins is sensed and converted into biochemical signals via the cadherin-catenin-actin complex.

Cell Junctions and the Extracellular Matrix: Structure, Function, and Signaling

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