Question

select all that apply
how do active and passive transport differ?

□ only active transport relies on an expenditure of energy by the cell itself, usually from atp.
□ cells use active transport only for organic molecules. inorganic molecules and ions are only moved by
□ only active transport can move a substance against its concentration gradient.
□ only active transport relies on carrier proteins.

Explanation:

1. Analyze the first option: Active transport requires energy (usually ATP) to move substances, while passive transport does not. So this statement is correct.
2. Analyze the second option: Active transport can move both organic and inorganic molecules/ions (e.g., ion pumps for inorganic ions), and passive transport also moves inorganic molecules (like diffusion of ions in some cases). So this statement is incorrect.
3. Analyze the third option: Passive transport moves substances down their concentration gradient, while active transport can move substances against (from low to high concentration) the concentration gradient. So this statement is correct.
4. Analyze the fourth option: Passive transport like facilitated diffusion also uses carrier proteins. So this statement is incorrect.

Answer:

• Only active transport relies on an expenditure of energy by the cell itself, usually from ATP.
• Only active transport can move a substance against its concentration gradient.