Question 1

Which of the following best describes the arrangement of phospholipids in the plasma membrane according to the fluid mosaic model?

Accepted Answer

Phospholipids are arranged in a bilayer with their polar heads facing the aqueous environments inside and outside the cell, and their non-polar tails facing each other.

Question 2

A patient has a genetic disorder that results in the absence of cholesterol in their plasma membranes. Which of the following is the most likely consequence?

Accepted Answer

The plasma membrane will become too fluid and less stable, making it more permeable to small molecules.

Question 3

Which of the following best explains why oxygen ($$O_2) $$and carbon dioxide ($$CO_2) $$can easily cross the plasma membrane?

Accepted Answer

They are small, non-polar molecules that diffuse through the lipid bilayer.

Question 4

Which of the following is a function of peripheral proteins in the plasma membrane?

Accepted Answer

Acting as enzymes or receptors on the membrane surface.

Question 5

A researcher observes that certain cells can recognize and bind to specific hormones due to specialized proteins on their plasma membrane. Which type of protein is primarily responsible for this function?

Accepted Answer

Peripheral proteins acting as receptors

Question 6

Which of the following best describes the role of carbohydrates in the plasma membrane?

Accepted Answer

They act as biological markers for cell recognition, such as blood group antigens.

Question 7

Which membrane junction would you expect to find in tissues that require a barrier to prevent leakage, such as the lining of the intestines?

Accepted Answer

Tight junctions

Question 8

During which phase of mitosis do chromosomes align at the metaphase plate, and what is the significance of this alignment?

Accepted Answer

Metaphase; it ensures that each daughter cell will receive an identical set of chromosomes.

Question 9

A mutation prevents the formation of spindle fibers during mitosis. Which stage of mitosis would be directly affected, and what would be the result?

Accepted Answer

Metaphase; chromosomes would not align at the metaphase plate.

Question 10

Which of the following best describes the function of desmosomes in tissues such as the skin?

Accepted Answer

They anchor adjacent cells together, providing mechanical strength.

Question 11

A scientist is studying a tissue where cells must rapidly communicate chemical signals, such as in cardiac muscle. Which membrane junction is most important for this function?

Accepted Answer

Gap junctions

Question 12

Which of the following statements about the cell cycle is correct?

Accepted Answer

Mitosis and cytokinesis together constitute the mitotic (M) phase.

Question 13

A cell is observed to have condensed chromosomes, a disappearing nucleolus, and separating centrioles. Which phase of mitosis is this cell in?

Accepted Answer

Prophase

Question 14

Which of the following best explains the importance of cytokinesis in the cell cycle?

Accepted Answer

It divides the cytoplasm and organelles, resulting in two separate daughter cells.

Question 15

A cell is unable to attach its cytoskeleton to the plasma membrane. Which component is most likely defective?

Accepted Answer

Peripheral proteins on the inner membrane surface

Question 16

Which of the following is true regarding glycoproteins and glycolipids in the plasma membrane?

Accepted Answer

They are only found on the outer surface and function as cell identity markers.

Question 17

A red blood cell is placed in a solution and begins to swell and burst. Which property of the plasma membrane is being overwhelmed in this scenario?

Accepted Answer

Its selective permeability to water and solutes

Question 18

Which of the following best describes the difference between integral and peripheral proteins in the plasma membrane?

Accepted Answer

Integral proteins span the membrane and function as channels or carriers, while peripheral proteins are attached to the membrane surface and have roles such as enzymes or receptors.

Question 19

During anaphase of mitosis, which of the following events occurs?

Accepted Answer

Centromeres split and sister chromatids are pulled toward opposite poles.

Question 20

A cell is observed to have a cleavage furrow forming. Which process is occurring, and what is the underlying mechanism?

Accepted Answer

Cytokinesis; a contractile ring of actin filaments is pinching the cytoplasm into two parts.

Chapter 3: Plasma Membrane Structure and Cell Division

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