Cell Membrane Function and Components Quiz

What is the main function of the cell membrane?

• To produce energy for the cell

• To form a boundary between the cell and its environment

• To store genetic information

Answer explanation

The main function of the cell membrane is to form a boundary between the cell and its environment, regulating what enters and exits the cell, thus maintaining homeostasis.

Tags

NGSS.MS-LS1-2

Which of the following is a component of a phospholipid?

• Amino acid

• Nucleotide

• Glycerol

Answer explanation

Glycerol is a key component of phospholipids, serving as the backbone to which fatty acids are attached. Amino acids and nucleotides are not part of phospholipid structure.

What role do cholesterol molecules play in the cell membrane?

• They strengthen the cell membrane

• They transport oxygen

• They produce proteins

Answer explanation

Cholesterol molecules play a crucial role in strengthening the cell membrane by providing stability and fluidity, which helps maintain the integrity of the membrane structure.

How do polar heads of phospholipids interact with water?

• They repel water

• They form hydrogen bonds with water

• They dissolve in water

• They break down water molecules

Answer explanation

The polar heads of phospholipids are hydrophilic, meaning they interact favorably with water by forming hydrogen bonds. This interaction helps to stabilize the structure of cell membranes.

What is the function of carbohydrates attached to membrane proteins?

• To provide energy

• To act as identification tags

• To transport nutrients

• To synthesize lipids

Answer explanation

Carbohydrates attached to membrane proteins serve as identification tags, helping cells recognize each other and communicate. This is crucial for processes like immune response and tissue formation.

What does the fluid-mosaic model describe?

• The arrangement of molecules in the cell membrane

• The structure of DNA

• The process of photosynthesis

• The function of ribosomes

Answer explanation

The fluid-mosaic model describes the arrangement of various molecules, including lipids and proteins, in the cell membrane, illustrating its dynamic and flexible nature.

What property allows the cell membrane to let some materials cross but not others?

• Selective permeability

• Osmosis

• Active transport

• Diffusion

Answer explanation

The cell membrane's property of selective permeability allows it to control which substances can enter or exit the cell, ensuring that essential materials pass through while blocking harmful ones.

What is the role of a receptor in cell communication?

• To detect a signal molecule and perform an action in response

• To produce energy for the cell

• To transport oxygen in the blood

• To break down waste materials

Answer explanation

Receptors are proteins that detect specific signal molecules, such as hormones or neurotransmitters, and initiate a cellular response. This is crucial for cell communication, making the first answer choice correct.

What type of molecules can cross the cell membrane and bind to an intracellular receptor?

• Nonpolar and relatively small molecules

• Large polar molecules

• Proteins and carbohydrates

• Water and salts

Answer explanation

Nonpolar and relatively small molecules can easily cross the cell membrane due to their hydrophobic nature, allowing them to bind to intracellular receptors. In contrast, large polar molecules and ions cannot pass through the lipid bilayer.

What happens when a receptor binds to a ligand?

• The receptor changes shape

• The cell membrane dissolves

• The cell undergoes mitosis

• The DNA replicates

Answer explanation

When a receptor binds to a ligand, it typically undergoes a conformational change, which can initiate a signaling cascade within the cell. This is crucial for cellular communication and response.