1.7 Exchange In the Gut

Question 1

Name 2 ways to maximise the rate of diffusion

Answer 1

• maximise the surface area

* minimise the distance the molecules need to move

Question 2

What happens in the small intestine?

Answer 2

The solutes are absorbed into the bloodstream

Question 3

What are villi?

Answer 3

Finger like projections which greatly increase the surface area for absorption to take place in the small intestine, they are the exchange surface for food molecules

Question 4

Where are the villi found?

Answer 4

They line the inner surface of the small intestine

Question 5

Name 3 adaptations of the villi that maximise their absorption of food molecules

Answer 5

• large surface area due to microvilli, so more diffusion can happen at once
• rich blood supply due to lots of capillaries produces a steep concentration gradient for efficient diffusion
• one cell thick cell wall so there is only a short distance the molecules have to travel in diffusion

Question 6

Why are enzymes in the gut important?

Answer 6

They break down the insoluble food into soluble food molecules that can be diffused