Chapter 6.4 (Exam 1) Active Transport

Question 1

Describe active transport.

Answer 1

Moves substances against a concentration and/or electrical gradient:

Requires energy (often ATP)

Directional

Question 2

What are the three types of proteins that active transport could use?

Answer 2

Uniporters

Symporters

Antiporters

Question 3

What are uniporters?

Answer 3

Active transport protein that move one substance in one direction

Question 4

What are symporters?

Answer 4

Active transport proteins that move two substances in one direction

Question 5

What are antiporters?

Answer 5

Active transport proteins that move two substances in two opposite directions

Question 6

What are known as coupled transporters? Why?

Answer 6

Symporters and antiporters because they transport two substances

Question 7

What does primary active transport require?

Answer 7

Requires direct hydrolysis of ATP

Question 8

Describe secondary active transport.

Answer 8

Energy comes from an ion concentration gradient (electrochemical gradient) that is established by primary active transport

Question 9

What is one major example of primary active transport?

Answer 9

The sodium–potassium (Na+–K+) pump is an integral membrane glycoprotein (an antiporter):

Brings two K+ ions into the cell and exports three Na+ ions

Question 10

Describe secondary active transport based on the sodium-potassium pump.

Answer 10

Once the Na+–K+ pump establishes a concentration gradient of Na+, passive diffusion of some Na+ back into the cell provides energy for the transport of glucose into the cell against its concentration gradient