Question 1

Which component of the animal extracellular matrix (ECM) primarily resists tensile (pulling) forces, similar to steel rods in reinforced concrete?

Accepted Answer

Collagen fibers

Question 2

A researcher observes that a plant’s petals fall off easily after a certain enzyme is applied. Which cell structure is most likely degraded, and what is its main molecular component?

Accepted Answer

Middle lamella; pectin

Question 3

Which type of cell junction in animal cells forms a watertight seal and is most commonly found in epithelial tissue?

Accepted Answer

Tight junctions

Question 4

In the analogy of reinforced concrete, which ECM component in animals is most similar to the 'concrete' that resists compression?

Accepted Answer

Proteoglycan ground substance

Question 5

Which protein family anchors the cytoskeleton to the ECM and helps transmit signals from the outside to the inside of animal cells?

Accepted Answer

Integrins

Question 6

A mutation prevents the formation of desmosomes in epithelial tissue. What is the most likely consequence?

Accepted Answer

Cells cannot resist pulling and shearing forces

Question 7

Which structure allows direct cytoplasmic communication between adjacent plant cells, enabling the transfer of small molecules and ions?

Accepted Answer

Plasmodesmata

Question 8

A hormone is found to be lipid-soluble. Where would you expect its receptor to be located, and what is the likely cellular response?

Accepted Answer

In the cytosol; alteration of gene expression

Question 9

Which process is responsible for turning off a phosphorylation cascade in cell signaling, and what is the enzyme involved?

Accepted Answer

Dephosphorylation; phosphatase

Question 10

A cell receives a signal from a distant cell via a hormone that cannot cross the plasma membrane. What is the correct sequence of events for signal transduction?

Accepted Answer

Hormone binds to cell surface receptor → signal transduction cascade → second messenger production

Question 11

Which of the following best describes the role of expansins in plant cell growth?

Accepted Answer

They disrupt cross-linking between microfibrils, allowing cell wall expansion

Question 12

Which equation best represents the osmotic pressure ($$\Pi) $$that contributes to turgor pressure in plant cells?

Accepted Answer

$$\Pi = iMRT$$

Question 13

Which of the following is NOT a function of the plasma membrane?

Accepted Answer

Synthesizing collagen fibers

Question 14

Which cell junction in animal cells allows the passage of small molecules and ions directly between adjacent cells?

Accepted Answer

Gap junctions

Question 15

A patient’s cells are unable to respond to a specific hormone, even though the hormone is present in the bloodstream. What is the most likely explanation?

Accepted Answer

The cells lack the appropriate signal receptor

Question 16

Which of the following best explains why only certain cells respond to a particular signaling molecule?

Accepted Answer

Only those cells have the correct signal receptor

Question 17

Which of the following is a direct result of integrin malfunction in animal cells?

Accepted Answer

Failure to anchor the cytoskeleton to the ECM

Question 18

Which structure in plant cells is most responsible for counteracting turgor pressure and maintaining cell shape?

Accepted Answer

Primary cell wall

Question 19

Which of the following is true about signal amplification in cell signaling?

Accepted Answer

A single hormone molecule can trigger the production of many second messengers

Question 20

Which of the following best describes the function of the secondary cell wall in mature plant cells?

Accepted Answer

It is found between the plasma membrane and primary cell wall and contains specialized substances like lignin or waxes depending on cell type

Cell-Cell Interactions: Structure, Function, and Communication in Multicellular Organisms

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