Question 1

Which of the following best describes the role of integrins in cell-ECM interactions, as illustrated in the first image?

Accepted Answer

Integrins act as transmembrane receptors that connect the extracellular matrix (ECM) to the actin cytoskeleton via adaptor proteins.

Question 2

A patient presents with a genetic disorder that results in defective collagen assembly. Which tissue would most likely be affected due to its reliance on collagen for tensile strength?

Accepted Answer

Bone, because collagen provides tensile strength and structural integrity.

Question 3

Which of the following ECM components is primarily responsible for the resistance to compression in cartilage, as depicted in the second and seventh images?

Accepted Answer

Proteoglycans and glycosaminoglycans (GAGs)

Question 4

A mutation in the gene encoding connexin proteins would most directly affect which cellular structure and function?

Accepted Answer

Gap junctions; direct cell-cell communication via ion and small molecule exchange

Question 5

Which of the following best explains why tight junctions are essential in epithelial tissues, as shown in the fifth image?

Accepted Answer

They create a seal that prevents paracellular movement of substances, maintaining distinct apical and basal domains.

Question 6

A researcher observes that cells in culture stop dividing when they lose contact with the ECM. This phenomenon is best explained by which concept?

Accepted Answer

Anchorage-dependent growth, which requires integrin-mediated signaling

Question 7

Which of the following statements about matrix metalloproteinases (MMPs) is correct?

Accepted Answer

MMPs are enzymes that degrade ECM components, facilitating tissue remodeling and cell migration.

Question 8

A drug that inhibits the function of claudins and occludins would most likely disrupt which cellular structure?

Accepted Answer

Tight junctions

Question 9

Which of the following best describes the molecular composition and function of the basal lamina?

Accepted Answer

It contains type IV collagen, laminin, nidogen, and perlecan, and provides structural support and a permeability barrier.

Question 10

Which of the following scenarios best illustrates the importance of cadherin-mediated cell adhesion?

Accepted Answer

A mutation in E-cadherin leads to loss of cell-cell adhesion in epithelial tissues, contributing to cancer metastasis.

Question 11

Which of the following equations best represents the relationship between the concentration of glycosaminoglycans (GAGs) and the osmotic pressure they generate in cartilage?

Accepted Answer

$$\Pi = iCRT$$

Question 12

A patient with Ehlers-Danlos syndrome has hyperflexible joints and fragile skin. This is most likely due to a defect in which ECM component?

Accepted Answer

Collagen

Question 13

Which of the following best explains why hyaluronate is abundant in synovial fluid of joints?

Accepted Answer

It acts as a highly hydrated, gel-like substance that lubricates and absorbs shock.

Question 14

Which of the following is a direct consequence of inhibiting matrix metalloproteinase (MMP) activity in a tumor microenvironment?

Accepted Answer

Reduced ECM remodeling, which may limit cancer cell invasion

Question 15

Which of the following best describes the difference between hemidesmosomes and desmosomes?

Accepted Answer

Hemidesmosomes anchor cells to the basal lamina via integrins, while desmosomes connect adjacent cells via cadherins.

Question 16

A scientist is studying a protein that binds to both collagen and integrins, facilitating cell migration during wound healing. This protein is most likely:

Accepted Answer

Fibronectin

Question 17

Which of the following best explains why loss of anchorage dependence is a hallmark of cancer cells?

Accepted Answer

Cancer cells can divide without integrin-mediated attachment to the ECM, allowing them to metastasize.

Question 18

Which of the following is a key feature of the epithelial-mesenchymal transition (EMT) during cancer metastasis?

Accepted Answer

Decreased cell-cell adhesion due to loss of cadherin expression

Question 19

Which of the following best describes the function of adhesive glycoproteins in the ECM?

Accepted Answer

They act as multi-adhesive organizers, linking cells to the ECM and other ECM components.

Question 20

A mutation in the gene encoding dystrophin leads to Duchenne muscular dystrophy. Which of the following best explains the molecular consequence of this mutation?

Accepted Answer

Loss of dystrophin disrupts the linkage between the cytoskeleton and the ECM, weakening muscle cell stability.

Cell Adhesions, Cell Junctions, and Extracellular Structures: Study Notes

Guida di studio - Domande di pratica

Study guide - Flashcard