Cell Membrane: Structure and Transport

What is the primary function of the cell membrane?

• To produce energy for the cell

• To control the movement of substances in and out of the cell

• To store genetic information

• To synthesize proteins

Which of the following components is a major part of the cell membrane structure?

• Nucleic acids

• Phospholipids

• Ribosomes

• Mitochondria

Explain how the structure of the phospholipid bilayer contributes to its function in the cell membrane.

• The bilayer allows for the free passage of all molecules.

• The hydrophobic tails prevent water-soluble substances from passing through easily.

• The bilayer is rigid and does not allow any movement.

• The hydrophilic heads repel water, preventing any interaction.

Which process involves the movement of molecules from an area of higher concentration to an area of lower concentration?

• Active transport

• Falling down

• Diffusion

• Endocytosis

Describe the role of proteins in the cell membrane.

• Proteins provide energy for the cell.

• Proteins act as channels or carriers to help transport substances across the membrane.

• Proteins store genetic information.

• Proteins are not involved in the cell membrane.

What is osmosis?

• The movement of solutes from a low concentration to a high concentration

• The movement of water molecules through a selectively permeable membrane from a region of low solute concentration to a region of high solute concentration

• The movement of water molecules through a selectively permeable membrane from a region of high solute concentration to a region of low solute concentration

• The movement of solutes through a membrane without the use of energy

How does active transport differ from passive transport?

• Active transport requires energy, while passive transport does not.

• Active transport moves substances down their concentration gradient, while passive transport moves them against it.

• Active transport only occurs in plant cells, while passive transport occurs in animal cells.

• Active transport involves the movement of water, while passive transport involves the movement of solutes.

Identify the type of transport that requires energy to move substances across the cell membrane.

• Facilitated diffusion

• Osmosis

• Active transport

• Simple diffusion