Primary and secondary active transport, and passive transport?

1. What is the difference between primary and secondary active transport?

Primary active transport involves the direct use of energy, usually in the form of ATP, to move molecules against their concentration gradient. This means that the molecules are being transported from an area of low concentration to an area of high concentration. Secondary active transport, on the other hand, uses the energy stored in the electrochemical gradient of one molecule to transport another molecule against its concentration gradient.

2. How does passive transport differ from active transport?

Passive transport does not require the direct use of energy, and instead relies on the natural movement of molecules from an area of high concentration to an area of low concentration. This can occur through processes such as diffusion, osmosis, and facilitated diffusion. Active transport, on the other hand, requires the use of energy to move molecules against their concentration gradient.

3. What is an example of primary active transport?

An example of primary active transport is the sodium-potassium pump, found in the cell membrane of many cells. This pump uses the energy from ATP to move sodium ions out of the cell and potassium ions into the cell, maintaining a concentration gradient that is essential for many cellular processes.

4. Can you explain the process of secondary active transport?

In secondary active transport, a molecule is moved against its concentration gradient by using the energy stored in the electrochemical gradient of another molecule. For example, glucose can be transported into cells against its concentration gradient by coupling its movement with the movement of sodium ions, which are moving down their concentration gradient.

5. How does osmosis differ from diffusion?

Osmosis is a specific type of passive transport that involves the movement of water molecules across a selectively permeable membrane, from an area of higher water concentration to an area of lower water concentration. Diffusion, on the other hand, refers to the overall movement of molecules, including ions and other substances, from an area of high concentration to an area of low concentration.