active transport

Question 1

What is active transport?

Answer 1

Active transport is the process where cells move substances against their concentration gradient (from lower to higher concentration) using energy.

Question 2

How does active transport differ from diffusion?

Answer 2

Unlike diffusion, which moves substances from high to low concentration (passive), active transport moves substances against their concentration gradient and requires energy.

Question 3

What proteins are responsible for active transport?

Answer 3

Pump proteins in the membrane are responsible for active transport. They move substances across the membrane, even when the concentration is higher inside than outside (or vice versa).

Question 4

How do pump proteins differ from channel proteins?

Answer 4

1. They require energy (active transport).
2. They move particles in one direction only.
3. They move particles against the concentration gradient.

Question 5

How do pump proteins work?

Answer 5

Pump proteins change between two conformations:

1. In one conformation, the particle enters the pump from one side of the membrane.
2. The protein changes shape to allow the particle to exit on the opposite side of the membrane.
3. The pump protein returns to its original shape, ready for the next cycle.

Question 6

What energy source do pump proteins typically use?

Answer 6

Most pump proteins use ATP to provide the energy needed to change their conformation and move particles across the membrane.

Question 7

Why are pump proteins important for the cell?

Answer 7

Pump proteins allow the cell to precisely control the content of its cytoplasm by selectively moving specific substances in or out, regardless of concentration gradients.

Question 8

Can a single pump protein move multiple types of substances?

Answer 8

No, each pump protein is usually specific to one type of particle, allowing for highly precise control over the cell’s internal environment.

Question 9

What is the primary difference between active transport and facilitated diffusion?

Answer 9

The primary difference is that active transport moves substances against their concentration gradient and requires energy, while facilitated diffusion moves substances down their concentration gradient without energy.