Question

1. which of the following statements describe situations of passive transport across a cell membrane? (choose all that apply)

water is moved across a membrane to dilute a molecule that is highly concentrated on the other side.
a cell removes specific molecules through a membrane based on size.
a molecule disperses to create a uniform concentration throughout a solution
a cell uses energy to move molecules across a membrane from an area of lower concentration to an area of higher concentration.

Explanation:

Passive transport is the movement of substances across a cell membrane without using cellular energy, following concentration gradients (from high to low concentration) or via passive mechanisms like osmosis, diffusion, or filtration.

1. Water moving to dilute a concentrated solute is osmosis, a type of passive transport.
2. Removing molecules based on size is filtration, a passive transport mechanism relying on pressure gradients.
3. Molecules dispersing to uniform concentration is simple diffusion, a core passive transport process.
4. Using energy to move molecules against a concentration gradient is active transport, not passive.

Answer:

• Water is moved across a membrane to dilute a molecule that is highly concentrated on the other side.
• A cell removes specific molecules through a membrane based on size.
• A molecule disperses to create a uniform concentration throughout a solution