B2 Food, Digestion & Enzymes Flashcards
What do proteases do?
Proteases break down proteins to amino acids.
What type of food group do amylase enzymes break down (and where do they do it) ?
Amylase enzymes break down starch to sugars.
They are made in the salivary glands, pancreas and small intestine.
What type of food group do protease enzymes break down?
Where are they made?
Protease enzymes break down proteins to amino acids.
They are made in the stomach, pancreas and small intestine.
What is the pH of bile?
Bile has an alkaline pH of about 8 to neutralise hydrochloric acid from the stomach.
How is the small intestine adapted for fast absorption of food?
The small intestine is adapted for fast absorption of food in 4 ways
- large surface area (villi)
- good blood supply
- wet
- thin wall
Why don’t enzymes work above 40OC?
Enzymes stop working above 40OC because they are proteins and protein denatures (changes shape) above this temperature. This changes the shape of the active site so they cannot speed up reactions any more.
What is amylase, what does it do and where does it do it?
Amylase is a carbohydrase enzyme which breaks down starch in the mouth and small intestine.
What happens in the digestive sytem?
The digestive system is an organ system in which food is digested and absorbed.
Why does the optimum (best) pH of digestive enzymes vary?
The optimum pH of digestive enzymes depends on the part of the digestive system where each enzyme works. Enzymes which work in the stomach have to work at a very low pH because the stomach is very acidic. The enzymes in the small intestine have to work at an alkaline pH.
What is the name of the 2 processes which move digested food from the small intestine into the blood?
- Active transport (which uses up energy) e.g Glucose
- Diffusion (slower but needs no energy)
What do our bodies use carbohydrates for?
Our bodies use carbohydrates for fuel for respiration.
Starch is a slow release fuel and and sugars such as glucose give us fuel quickly.
What is the optimum pH for the activity of amylase?
The optimum pH for the activity of amylase is pH7
What do lipases do?
Lipases break down lipids (fats) to glycerol and fatty acids.
Give another example of a food rich in fat.
There are many foods rich in food. Ice cream is obviously one but also;
butter, oil, lard, ghee, margarine, avacado, oily fish, nuts, peanut butter, sausages, chocolate, cream, greek yoghurt, flaky pastry and any fried food.
Which part of an enzyme molecule is involved in chemical reactions?
The active site is the part of an enzyme molecule involved in chemical reactions