Cell Structure and Function

What is the outer rigid covering of plant cells?

• Plasma membrane
• Cytoplasm
• Nucleus
• Cell wall

What type of transport moves molecules against their concentration gradient?

• Passive transport
• Simple diffusion
• Osmosis
• Active transport

Why do polar molecules need carrier proteins to cross the membrane?

• They are too large to pass through
• They carry a negative charge
• They are harmful to the cell
• They cannot pass through the nonpolar lipid bilayer

What is the movement of water across a membrane called?

• Diffusion
• Facilitated diffusion
• Active transport
• Osmosis

What process allows neutral solutes to cross the membrane along their concentration gradient?

• Osmosis
• Active transport
• Endocytosis
• Simple diffusion