Biological Molecules Flashcards
Name the elements present in a carbohydrate
Carbon, C
Oxygen, O
Hydrogen, H
Name the elements present in a lipid
Carbon, C
Hydrogen, H
Oxygen, O
Name the elements present in a protein
Carbon, C
Hydrogen, H
Oxygen, O
Nitrogen, N
What are the basic units of carbohydrates?
Simple sugars (monosaccharides) such as glucose and fructose.
Name 2 monosaccharides
Glucose
Fructose
Give 2 examples of lipids
Fats and oils
Define a lipid
A large molecule made from smaller units of fatty acids and glycerol
Define a protein
A large molecule made from smaller units of amino acids.
Describe the test for glucose
- Benedict’s reagent
- blue -> brick red
- heat after adding reagent
Describe the test for starch
- iodine test
- orange/ brown -> blue/black
Describe the test for lipids
- emulsion test
- add ethanol to solution and then add it a test tube of water
- turns into milky emulsion
Describe test for proteins
- Biuret reagent
- blue -> lilac / purple
Define an enzyme
A protein that functions as a biological catalyst- a substance that speeds up a chemical reaction without being changed by the reaction.
Describe how an enzyme works.
- Substrate collides with active site of enzyme and becomes attached, forming an enzyme substrate complex.
- Enzyme catalyses the breakdown of the substrate
- Products are released from the active site
Describe the effect of increasing temperature on the rate of enzyme activity.
- an increase in temp will initially increase rate of activity
- enzymes and substrates have more kinetic energy and therefore collide more often, forming more complexes
- if temp exceeds optimum, active site loses shape and enzyme becomes denatured
- no more complexes formed, so rate decreases.
Describe the effect of increasing pH on the rate of enzyme activity.
All enzymes have an optimum pH at which they work best. Either side of this pH, the active site loses its shape and the enzyme becomes denatured, meaning rate of activity will decrease.
