Digestion Flashcards
What are enzymes?
biological catalysts - they speed up chemical reactions without being changed or used up
- large proteins
Why don’t enzymes work once they have been denatured?
because the substrate cannot fit into the active site
Why does starch, proteins and fat need to be broken down into smaller molecules?
because they are big molecules, which are too big to pass through the walls of the digestive system
smaller molecules are easily absorbed into the bloodstream
Describe how enzymes reach food molecules
digestive enzymes are produced by specialized cells in glands and the lining of the gut
1) enzymes pass out of the cell, into the digestive system
2) they come into contact with food molecules
3) they catalyze the break down of large insoluble food molecules into smaller soluble molecules
Where is AMYLASE produced and what does it do?
- produced in the salivary glands and pancreas
What is the difference between carbohydrase and amylase
Carbohydrases break down carbohydrates to simple sugars. Amylase is a carbohydrase that breaks down starch.
Where is carbohydrase produced
salivary glands, pancreas and small intestine
Where is PROTEASE produces and what does is do?
stomach, pancreas and small intestine
breaks down proteins to peptides or amino acids
Where is LIPASE produces and what does is do?
produced in pancreas and small intesitine
fats into fatty acids and glycerol
What are the products of dgestion used for?
to build new carbohydrates, lipids and proteins. Some glucose is used in respiration.
Where is bile made and where is it stored
describe its features and what is does
how does it increase the rate of reaction
Bile is made in the liver and stored in the gall bladder. It is alkaline to neutralize hydrochloric acid from the stomach.
It also emulsifies fat to form small droplets which increases the surface area for enzymes to act on.
The alkaline conditions and large surface area increase the rate of fat breakdown by lipase.
Why is active transport used in the gut?
because there is a lower conc of nutrients in the gut, but a higer conc of nutrients in the blood
what is the ph of bile ?
8
