Biological molecules Flashcards
What are the three main biological molecules?
- Carbohydrates
- Proteins
- Lipids
What are carbohydrates?
Molecules made up of simple sugars
What elements do carbohydrates contain?
Carbon, hydrogen and oxygen.
What are starch and glycogen?
Large complex carbohydrates made up of smaller units (glucose and maltose molecules) joined together in a long chain.
What are proteins?
A long chain of amino acids
What elements do proteins contain?
Carbon, hydrogen, oxygen and nitrogen.
What are lipids?
Molecules made up of fatty acids and glycerol
What elements do lipids contain?
Carbon, hydrogen and oxygen.
How do you test for glucose?
Benedict’s reagent
What colour is benedicts reagent?
Blue
What happens if glucose is present?
A coloured precipitate is formed. The colour of the precipitate changes from: blue-green-yellow-orange-brick red
The higher the concentration of glucose…
… The further the colour change goes!
How do you test for starch?
Iodine test
If starch is present?
Sample changes colour to a dark blue-black one
If theres no starch?
Sample stays browny-orange
What are enzymes?
Biological catalysts in metabolic reactions
What is a catalyst?
A substance which increases the speed of a reaction without being changed or used in the reaction.
What are enzymes made of?
Proteins - long chain of amino acids folded into unique shapes to help the enzymes do their job
What is a substrate?
A molecule that is changed in a reaction
What is the active site?
The part where the substrate joins onto the enzyme.
What has to be correct to fit the active site?
The shape of the substrate otherwise the enzyme wont work
What is the model called when the substrate fits the active site perfectly?
The “lock and key” model
The higher the temperature…
The quicker the rate of the reaction (up to a certain point) as the enzymes and substrate particles have more energy, so more about more - higher collision rate
The lower the temperature…
The slower the reaction, so lower collision rate
