Plasma Membrane: Structure, Function, and Role in Cell Signaling

Question 1

The plasma membrane plays a crucial role in many cellular processes. Which of these functions is NOT a primary responsibility of the plasma membrane?

Accepted Answer

Producing energy through cellular respiration

Answer

Regulating the movement of substances into and out of the cell

Answer

Providing a protective barrier for the cell's internal environment

Answer

Facilitating communication between cells through signaling pathways

Question 2

Which of the following is **not** a type of membrane protein?

Accepted Answer

Lipid-associated

Answer

Integral

Answer

Peripheral

Answer

Glycoprotein

Question 3

The plasma membrane contributes to cellular homeostasis primarily by regulating:

Accepted Answer

Ion transport

Answer

Macromolecule synthesis

Answer

Cell division

Answer

Protein degradation

Question 4

The lipid bilayer of the plasma membrane primarily consists of:

Accepted Answer

Phospholipids and cholesterol

Answer

Proteins and carbohydrates

Answer

Nucleic acids and lipids

Answer

Carbohydrates and proteins

Question 5

Which of the following is **not** a function of membrane carbohydrates?

Accepted Answer

Ion transport

Answer

Cell recognition

Answer

Immune response

Answer

Protein folding

Question 6

The fluid mosaic model describes the plasma membrane as:

Accepted Answer

Both b and c

Answer

A rigid and static structure

Answer

A fluid and dynamic structure

Answer

A mosaic of different components

Question 7

Which of the following is **not** a consequence of the selective permeability of the plasma membrane?

Accepted Answer

Free movement of all substances

Answer

Maintenance of cellular homeostasis

Answer

Differential distribution of ions and molecules

Answer

Regulation of cell volume

Question 8

Which of these is NOT a significant constituent of the plasma membrane?

Accepted Answer

Nucleic acid

Answer

Phospholipids

Answer

Cholesterol

Answer

Glycoproteins

Question 9

Identify the disease that is associated with a defect in plasma membrane ion transport.

Accepted Answer

Cystic fibrosis

Answer

Sickle cell anemia

Answer

Hemophilia

Answer

Down syndrome

Question 10

According to the fluid mosaic model, how is the plasma membrane structured?

Accepted Answer

A mosaic of proteins set in a lipid bilayer

Answer

A static, inflexible lipid layer

Answer

A dynamic, semi-fluid bilayer

Answer

A single layer of phospholipids

Question 11

How does the concentration gradient influence membrane transport?

Accepted Answer

Supports movement from high to low concentration

Answer

Supports movement from low to high concentration

Answer

No effect on membrane transport

Answer

Varies depending on the molecule being transported

Question 12

Which of the following is a major component of the plasma membrane?

Accepted Answer

Phospholipids and cholesterol

Answer

Carbohydrates and proteins

Answer

Proteins only

Answer

Carbohydrates and lipids

Question 13

What is the primary function of the phospholipid bilayer in the plasma membrane?

Accepted Answer

Maintain cell shape and protect the cell's interior

Answer

Facilitate the passage of all types of molecules

Answer

Transmit nerve impulses

Answer

Recognize and bind to specific molecules

Question 14

Which of the following processes allows polar molecules, such as glucose, to cross the plasma membrane?

Accepted Answer

Facilitated diffusion

Answer

Simple diffusion

Answer

Active transport

Answer

Exocytosis

Question 15

Which of the following is NOT a type of cell adhesion molecule?

Accepted Answer

Phospholipids

Answer

Integrins

Answer

Cadherins

Answer

Glycoproteins

Question 16

Which of the following disorders is caused by a defect in plasma membrane proteins?

Accepted Answer

Cystic fibrosis

Answer

Sickle cell anemia

Answer

Tay-Sachs disease

Answer

Huntington's disease

Question 17

What impact does a higher lipid-to-protein ratio have on the fluidity and permeability of a plasma membrane?

Accepted Answer

Increases both fluidity and permeability

Answer

Decreases fluidity and increases permeability

Answer

Decreases both fluidity and permeability

Answer

Has no effect on fluidity or permeability

Question 18

Which of the following is NOT a component of the phospholipid bilayer of the plasma membrane?

Accepted Answer

Proteins

Answer

Phospholipids

Answer

Cholesterol

Answer

Glycoproteins

Question 19

What type of membrane transport mechanism is facilitated by specific membrane proteins and does not require the input of energy?

Accepted Answer

Facilitated diffusion

Answer

Simple diffusion

Answer

Active transport

Answer

Osmosis

Question 20

Reworded: Which type of cell junction primarily anchors cells together, providing mechanical strength?

Accepted Answer

Revised: Desmosomes

Answer

Revised to make more specific: Tight junctions

Answer

Revised to make more specific: Gap junctions

Answer

Revised to make more specific: Plasmodesmata

Question 21

Reworded: What is the main function of the glycocalyx that covers the outer surface of the plasma membrane?

Accepted Answer

Revised: To facilitate cell-cell recognition and adhesion

Answer

Revised: To protect the cell surface from mechanical damage

Answer

Revised: To regulate membrane permeability

Answer

Rephrased: To anchor the cell to the extracellular matrix

Question 22

Reworded: What is the primary role of the sodium-potassium pump in the plasma membrane?

Accepted Answer

Revised to emphasize primary function: To establish and maintain the resting membrane potential

Answer

Revised: To transport glucose into the cell

Answer

Revised: To remove waste products from the cell

Answer

Revised: To synthesize proteins

Question 23

Reworded: Which of the following is NOT a recognized type of cell signaling?

Accepted Answer

Revised to avoid confusion: Synaptic signaling

Answer

Rephrased: Endocrine signaling

Answer

Rephrased: Paracrine signaling

Answer

Revised: Autocrine signaling

Question 24

Reworded: Which of the following components is not typically found in the plasma membrane?

Accepted Answer

Rephrased: Nucleic acids

Answer

Rephrased: Phospholipids

Answer

Rephrased: Cholesterol

Answer

Rephrased: Glycoproteins

Question 25

Reworded: What is the primary function of the phospholipid bilayer in the plasma membrane?

Accepted Answer

Revised to emphasize primary function: To serve as a selectively permeable barrier

Answer

Revised: To maintain cellular homeostasis

Answer

Revised: To facilitate cell signaling

Answer

Revised: To anchor membrane proteins

Question 26

Reworded: Which factors can influence the permeability of the plasma membrane?

Accepted Answer

Combined for inclusiveness: All of the above

Answer

Revised: Lipid composition

Answer

Revised: Temperature

Answer

Revised: pH

Question 27

Reworded: Which type of transport protein requires ATP to move molecules across the plasma membrane?

Accepted Answer

Revised to emphasize ATP requirement: Pumps

Answer

Revised: Channel proteins

Answer

Revised: Carrier proteins

Answer

Revised: Facilitated diffusion

Question 28

Which of the following correctly describes the energy requirements of passive and active transport across the plasma membrane?

Accepted Answer

Active transport requires energy, while passive transport does not.

Answer

Passive transport requires energy, while active transport does not.

Answer

Both require energy, but active transport moves molecules against their concentration gradient.

Answer

Both require energy, but passive transport moves molecules down their concentration gradient.

Question 29

How does the plasma membrane play a role in cell-cell recognition?

Accepted Answer

By displaying specific surface molecules that interact with other cells.

Answer

By regulating the movement of ions and molecules between cells.

Answer

By providing a physical barrier between cells.

Answer

By initiating cell signaling events.

Question 30

Which of the following is not a component of the plasma membrane?

Accepted Answer

Starch

Answer

Cholesterol

Answer

Phospholipids

Question 31

The lipid bilayer of the plasma membrane is impermeable to which type of molecule?

Accepted Answer

Hydrophilic molecules

Answer

Small ions

Answer

Hydrophobic molecules

Question 32

Which of the following is a characteristic of a healthy plasma membrane?

Accepted Answer

High fluidity and low asymmetry

Answer

Low fluidity and high asymmetry

Answer

High rigidity and low asymmetry

Question 33

What is the primary structural component of the plasma membrane?

Accepted Answer

Phospholipid bilayer

Answer

Lipopolysaccharide bilayer

Answer

Lipoprotein monolayer

Answer

Glycoprotein monolayer

Question 34

The plasma membrane maintains cellular volume primarily by:

Accepted Answer

Regulating the osmotic flow of water across the membrane

Answer

Controlling the flow of oxygen across the membrane

Answer

Actively pumping ions against their concentration gradients

Answer

Adjusting the membrane surface area through endocytosis and exocytosis

Question 35

A major consequence of significant plasma membrane damage can be:

Accepted Answer

Cell lysis due to loss of osmotic balance

Answer

Cell differentiation into specialized cell types

Answer

Cell division and uncontrolled proliferation

Question 36

Which molecule is NOT typically found in the composition of the plasma membrane?

Accepted Answer

Starch

Answer

Glycoproteins

Answer

Phospholipids

Answer

Cholesterol

Question 37

The primary function of the plasma membrane is to:

Accepted Answer

Maintain cellular homeostasis and facilitate communication with the extracellular environment

Answer

Store genetic material in the form of DNA

Answer

Synthesize proteins for cellular processes

Question 38

Membrane asymmetry refers to:

Accepted Answer

The non-uniform distribution of lipids and proteins within the two leaflets of the plasma membrane

Answer

The selective permeability of the plasma membrane to certain molecules

Question 39

Which technique provides the highest resolution images of the plasma membrane structure?

Accepted Answer

Electron microscopy

Answer

X-ray diffraction

Answer

Magnetic resonance imaging

Answer

Light microscopy

Question 40

**Enhanced:** What is the primary function of the glycocalyx associated with the plasma membrane?

Accepted Answer

**Enhanced:** Protection against mechanical damage and facilitation of cell-cell adhesion.

Answer

Regulation of the passage of substances across the membrane.

Answer

Generation of electrical signals for intercellular communication.

Question 41

**Enhanced:** Which of the following factors **primarily** influences the fluidity of the plasma membrane?

Accepted Answer

**Enhanced:** Lipid composition and temperature.

Answer

Carbohydrate content.

Answer

Concentration of oxygen.

Answer

pH and ionic strength.

Question 42

**Enhanced:** How does the plasma membrane contribute to the maintenance of cellular homeostasis?

Accepted Answer

**Enhanced:** Regulation of the movement of ions and molecules across the membrane.

Answer

Synthesis of proteins necessary for cell function.

Answer

Storage of genetic material for cellular reproduction.

Question 43

**Enhanced:** Which of the following **is not** a component of the plasma membrane?

Accepted Answer

**Enhanced:** Hemoglobin.

Answer

Proteins.

Answer

Phospholipids.

Answer

Cholesterol.

Question 44

**Enhanced:** What is the **primary** function of the plasma membrane?

Accepted Answer

**Enhanced:** Regulating the entry and exit of substances.

Answer

Storing genetic material.

Answer

Providing structural support.

Answer

Synthesizing proteins.

Question 45

**Enhanced:** Which of the following transport mechanisms **does not** involve the direct movement of substances across the plasma membrane?

Accepted Answer

**Enhanced:** Facilitated diffusion.

Answer

Simple diffusion.

Answer

Endocytosis.

Answer

Osmosis.

Question 46

**Enhanced:** What is the role of transmembrane proteins in cell signaling?

Accepted Answer

**Enhanced:** To transmit signals between the extracellular and intracellular environments.

Answer

Regulating protein synthesis.

Answer

Producing energy.

Question 47

**Enhanced:** Which of the following factors affects the permeability of the plasma membrane?

Accepted Answer

**Enhanced:** Temperature.

Answer

Age of the cell.

Answer

Cell size.

Answer

Hormone levels.

Question 48

**Enhanced:** What is the main difference between the inner and outer layers of the plasma membrane?

Accepted Answer

**Enhanced:** Lipid composition.

Answer

Protein content.

Answer

Thickness.

Answer

Carbohydrate composition.

Question 49

**Enhanced:** Which of the following is a consequence of membrane fluidity?

Accepted Answer

**Enhanced:** Ability of the membrane to change shape and move.

Answer

Decreased membrane permeability.

Answer

Reduced cell signaling.

Answer

Increased membrane rigidity.

Question 50

Which of the following techniques is used to study the structure of the plasma membrane?

Accepted Answer

Electron microscopy

Answer

Gel electrophoresis

Answer

PCR

Answer

Western blotting

Question 51

How does the plasma membrane contribute to maintaining cellular homeostasis?

Accepted Answer

Regulates movement of substances and maintains ionic balance

Answer

Provides energy for cellular processes

Answer

Controls cell division