B3 Flashcards
What is a tissue?
A group of cells with similar structure and function
What are organs?
A group of tissues performing specific functions
What does the liver do in the digestive system?
Produces bile
What does the stomach do in the digestive system?
Breaks down large insoluble molecules into smaller soluble molecules
What does the small intestine do in the digestive system?
breaks down large insoluble molecules into smaller soluble molecules and absorption into blood
What does the large intestine do in the digestive system?
absorbs water from undigested food
What do villi do?
They increase the surface area of the small intestine because of their shape, so more nutrients can be absorbed
Describe carbohydrates
- provide us with fuel to carry out reactions
- contains C, H, O and made from units of sugar
Describe lipids
- are fats and oils
- made up of 3 fatty acids and 1 glycerol
-efficient energy store in the body and source of energy, role in cell membrane and as hormones - different combination of fatty acids determines the nature of lipid
Describe proteins
- used for building up cells and tissues, and enzymes
- Made up of amino acids
What breaks down carbohydrates/starch?
Amylase
What does lipase break down?
lipids
What breaks proteins down?
Protease
How is digestion made efficient?
- stomach acid kills bacteria and optimum pH for protease
- bile made in liver neutralises stomach acid
What is emulsification?
- bile breaks down large drops of fat into smaller ones, increasing their surface area
What happens once an enzyme has reached its optimum temperature?
Its active site denatures, and the substrate no longer fits the altered shape
What effect does a change of pH have on an enzyme?
- If it’s not the optimum, the active site denatures
What can enzymes be used for?
- build big molecules from small ones
- break big molecules into small ones
- change a molecule into another molecule
What are the results of Benedict’s test?
blue- light green = little sugar present
blue- brick red = positive result, sugar is present
T or F: In Benedict’s test, the sample must be heated
True
What are the results of Biuret Reagent?
Blue-lilac = protein is present
What are the results of iodine test?
orange - blue/black = starch is present
What are the results of ethanol test?
milky white emulsion forms in presence of lipid
What is a buffer?
a solution at a certain pH
