Active Transport

Question 1

active transport definition

Answer 1

Active transport uses energy to move molecules and ions across membranes usually against the concentration gradient

Question 2

how are carrier proteins involved in active transport?

Answer 2

• a molecule attaches to the carrier protein which causes the protein to change shape
• this moves the molecule across the membrane to the other side

Question 3

how does active transport acquire energy?

Answer 3

• it uses ATP produced through respiration

- ATP undergoes a hydrolysis reaction producing ATP and P this releases energy so solutes can be transported

Question 4

how are co-transporters involved in active transport?

Answer 4

• they bind two molecules at a time
• the concentration gradient of one of the molecules allows the other molecule to move against its concentration gradient

Question 5

what is co-transport in the mammalian ileum?

Answer 5

• glucose is absorbed into the blood stream in the small intestine
• in the ileum the concentration of glucose is too low for glucose to diffuse out of the blood so co transport is used to absorb glucose fro the lumen of ileum

Question 6

Co-transport in the mammalian ileum (stage 1)

Answer 6

-sodium ions are actively transported out of the ileum epithelia cells into the blood by the sodium potassium pump this creates a concentration gradient as there’s a higher concentration gradient of sodium ions outside of the cell

Question 7

Co-transport in the mammalian ileum (stage 2)

Answer 7

-sodium ions move down their concentration gradient from the lumen of ileum into the epithelial cell via the sodium glucose co-transporter protein

Question 8

Co-transport in the mammalian ileum (stage 3)

Answer 8

• the cotta spotter carries glucose into the cell with the sodium
• this causes the concentration of glucose inside the cell to increase

Question 9

Co-transport in the mammalian ileum (stage 4)

Answer 9

• glucose diffuses out of the cell and into the blood

- glucose moves down its concentration gradient through a protein channel by facilitated diffusion

Question 10

what’s the difference between active transport and facilitated diffusion?

Answer 10

• active transport requires energy

- active transport moves against the concentration gradient