Question

select all that apply
which of the following are transport mechanisms used by bacteria to take in nutrients? more than one answer may be correct.

• passive diffusion
• facilitated diffusion
• osmosis
• secondary active transport

Explanation:

All listed mechanisms are used by bacteria for nutrient uptake:

1. Passive diffusion allows small, nonpolar nutrients to cross the cell membrane down their concentration gradient without energy or carriers.
2. Facilitated diffusion uses membrane carrier proteins to transport larger/polar nutrients down their concentration gradient, no energy required.
3. Osmosis is the diffusion of water (a critical nutrient/solvent) across the membrane, driven by solute concentration differences.
4. Secondary active transport uses the electrochemical gradient of one substance (e.g., protons) to drive the transport of nutrients against their concentration gradient, indirectly using energy.

Answer:

A. Passive diffusion, B. Facilitated diffusion, C. Osmosis, D. Secondary active transport