MCQ on Role of Plasma Membrane

here are some multiple-choice questions (MCQs) about “Plasma Membrane Structure and Function: Key Role in Cell Homeostasis,” along with detailed answers:

Question 1: Which of the following components make up the plasma membrane’s basic structure?

A) Nucleic acids and proteins
B) Carbohydrates and lipids
C) Proteins and lipids
D) Carbohydrates and nucleic acids

Answer 1: C) Proteins and lipids

Explanation: The plasma membrane consists of a lipid bilayer made up of phospholipids and embedded proteins. This lipid bilayer forms the basic structural framework of the membrane.

Question 2: What is the main function of the plasma membrane in a cell?

A) Energy production
B) Cell division
C) Transport of molecules in and out of the cell
D) Protein synthesis

Answer 2: C) Transport of molecules in and out of the cell

Explanation: The plasma membrane plays a crucial role in regulating the passage of molecules, ions, and nutrients into and out of the cell, maintaining the cell’s internal environment and facilitating various cellular processes.

Question 3: Which type of molecules are often found in the hydrophobic interior of the lipid bilayer?

A) Water-soluble molecules
B) Proteins
C) Carbohydrates
D) Lipids

Answer 3: D) Lipids

Explanation: The hydrophobic interior of the lipid bilayer is composed of fatty acid chains of phospholipids, making it impermeable to water-soluble molecules. Lipids are the main components of this hydrophobic region.

Question 4: What is the role of integral membrane proteins in the plasma membrane?

A) They provide structural support to the membrane.
B) They anchor the membrane to the cytoskeleton.
C) They regulate the passage of molecules across the membrane.
D) They are involved in energy production.

Answer 4: C) They regulate the passage of molecules across the membrane.

Explanation: Integral membrane proteins span the entire lipid bilayer and serve as channels, carriers, receptors, and enzymes that are essential for controlling the movement of substances across the plasma membrane.

Question 5: Which process allows the plasma membrane to engulf large particles by forming vesicles?

A) Active transport
B) Facilitated diffusion
C) Exocytosis
D) Endocytosis

Answer 5: D) Endocytosis

Explanation: Endocytosis is the process by which cells engulf large particles or substances from the extracellular environment by forming vesicles from the plasma membrane.

Question 6: Which of the following is a characteristic of the plasma membrane’s selective permeability?

A) It allows all molecules to freely pass through.
B) It only allows water molecules to pass through.
C) It allows certain molecules to pass through while restricting others.
D) It is impermeable to all substances.

Answer 6: C) It allows certain molecules to pass through while restricting others.

Explanation: The plasma membrane is selectively permeable, meaning it allows the passage of specific molecules and ions while blocking others, based on their size, charge, and lipid solubility.

Question 7: Which of the following processes requires energy to move molecules against their concentration gradient?

A) Simple diffusion
B) Facilitated diffusion
C) Osmosis
D) Active transport

Answer 7: D) Active transport

Explanation: Active transport is a process that moves molecules against their concentration gradient, requiring energy (usually from ATP) to pump substances across the plasma membrane.

Question 8: What is the significance of cell recognition proteins in the plasma membrane?

A) They provide mechanical support to the cell.
B) They are responsible for cell locomotion.
C) They help the immune system recognize foreign cells.
D) They aid in cell division.

Answer 8: C) They help the immune system recognize foreign cells.

Explanation: Cell recognition proteins, also known as glycoproteins, play a vital role in immune response by helping immune cells distinguish between self and non-self cells. They are involved in cell-cell recognition and cell signaling.

Question 9: What term is used to describe the movement of water molecules across a selectively permeable membrane?

A) Osmosis
B) Diffusion
C) Active transport
D) Endocytosis

Answer 9: A) Osmosis

Explanation: Osmosis is the process of water molecules moving from an area of lower solute concentration to an area of higher solute concentration through a selectively permeable membrane.

Question 10: Which organelle produces phospholipids and helps in membrane repair and growth?

A) Nucleus
B) Mitochondria
C) Endoplasmic reticulum
D) Golgi apparatus

Answer 10: C) Endoplasmic reticulum

Explanation: The endoplasmic reticulum (ER) is involved in the synthesis of lipids, including phospholipids, which are essential components of the plasma membrane. The ER plays a role in membrane repair and growth.