Yr 11 - SCB - Digestion (biology)

Question 1

Define physical digestion

Answer 1

is the process of breaking food down into smaller pieces

Question 2

Define chemical digestion

Answer 2

breaking down large insoluble molecules into small soluble molecules

Question 3

Why is physical digestion necessary

Answer 3

lets food pass through the digestive system easier and provide a larger surface area for enzymes

Question 4

Why is chemical digestion necessary

Answer 4

Molecules must be small and soluble so that they may be absorbed into the blood at the villi in the small intestine

Question 5

Adaptations of herbivore

Answer 5

• teeth to grind/chew Cellulose walls
• Cellulose digesting bacteria in gut that produce enzyme
• gut is long to increase digestion time

Question 6

Adaptations of carnivore

Answer 6

• teeth adapted to rip/tear meat, meat is not chewed for long
• stomach is site for protein digestion so can be large
• enzymes are not produced in the gut so it is not large as it does not do much digestion

Question 7

how do herbivores digest plant cell walls

Answer 7

plant cell walls are made of cellulose which is hard to digest. Mammals do not produce an enzyme that can digest cellulose. instead they have bacteria in the gut that can produce the enzyme - cellulase.

Question 8

What is Peristalsis?

Answer 8

Peristalsis is a series of wave-like muscle contractions that moves food to different processing stations in the digestive tract.

Question 9

What is bile and what does it do?

Answer 9

made by the liver and is stored in the gall bladder. It neutralises the acid from the stomach and provides the alkaline conditions needed for the enzymes in the small intestine. Bile also emulsifies fats which is the process of breaking fat globules into smaller droplets for greater surface area.