Digestion Flashcards
(38 cards)
What is the function (job) of carbohydrates in the body?
Act as a source of energy
Which foods are major sources of carbohydrates?
Potatoes, rice, pasta, cereals
What is the function (job) of proteins in the body?
Used for growth and repair
Which foods are major sources of proteins?
Meat, eggs, cheese, beans, nuts and seeds
What is the main function (job) of lipids?
- Used as a source of energy
- Make up the cell membranes
Which foods are major sources of lipids?
Butter, meat, plant oils, oily fish, nuts and seeds
Name three polymers of glucose.
- Starch
- Cellulose
- Glycogen
What happens to glucose molecules once absorbed by the body?
- Used for respiration
- Reassembled into glycogen and stored in the liver
What are proteins made up of?
Amino acids
What happens to excess amino acids?
They are broken down in the liver
What are lipids made up of?
Fatty acids and glycerol
Describe a positive food test result for sugars.
Benedict’s solution turns from blue to orange-brown when heated
Describe a positive food test result for starch.
Iodine turns from yellow to blue-black
Describe a positive food test result for proteins.
Biuret solution turns from blue to purple.
Describe a positive emulsion test result for lipids.
Ethanol turns cloudy.
What is the function (job) of the small intestine?
Absorption of simple sugars, amino acids, fatty acids and glycerol
What is the function (job) of the large intestine?
Absorption of water
What are villi?
Folds in the wall of the small intestine that provide a large surface area for absorption
What are microvillli?
Smaller folds on the surface of villi, which are folds found on the surface of the instestinal lining
How is the small intestine adapted for absorption?
- Very large surface area due to villi and microvilli
- Large blood supply
What are enzymes?
Biological catalysts that speed up chemical reactions
What is an active site?
The part of an enzyme that a specific substrate can fit into
What is a substrate?
A substance that fits into an enzyme
Describe the 3 steps to enzyme action.
- Substrate attaches to the active site of the enzyme.
- The enzyme catalyses and breaks down the substrate.
- The products are released from the active site.
