Question

Cells move materials in and out in two ways. Define the terms: A) Passive transport: Movement of molecules across the cell membrane without energy input. B) Active transport: Movement of molecules across the cell membrane using energy, typically against a concentration gradient.

Answer 1

Passive transport is the movement of molecules across a cell membrane without the need for energy, typically moving from areas of high concentration to low. Active transport requires energy and moves substances against a concentration gradient, from areas of low concentration to high.

Step-by-step explanation:

Passive transport refers to the movement of molecules across the cell membrane without the use of cellular energy or ATP. This generally occurs across a concentration gradient, meaning from areas of higher concentration to areas of lower concentration. An example of passive transport is osmosis, which is the movement of water across the cell membrane.

On the other hand, active transport is a biochemical process that requires the use of energy, typically ATP, to move substances against a concentration gradient, i.e., from an area of lower concentration to an area of higher concentration. An example of active transport is the sodium-potassium pump, a system that pumps sodium ions out and potassium ions into the cell, thus maintaining a balance of these ions.

Learn more about Cell Transport