Enzymes Flashcards
Catalyst
Speeds up the rate of a reaction. Can be reused because they do not change as a result of the reaction.
Enzyme
A protein catalyst.
Allows chemical reactions at body temperature.
Why are enzymes necessary?
They increase rate of chemical reactions without increasing temperature (no damage to protein and cells)
Activation energy
Energy required to initiate a chemical reaction.
Enzymes do not change what?
The amount of energy available
Substrate
A molecule that attaches to the active site of an enzyme
Active site
Area of enzyme that combines with a substrate molecule.
Each enzyme is specific for a certain substrate.
Cofactors
Inorganic molecules that change the shape of an active site.
E.g) iron, zinc, calcium, minerals
Coenzymes
Organic molecules that change shape of the active site.
E.g) vitamins
Feedback inhibition
Occurs when high levels of a substance will result in a decrease in its production.
Naming an enzyme
Substrate name + ase
Lock and key hypothesis
- Active site of an enzyme fits the substrate molecules
- Forms an enzyme substrate complex
Factors affecting enzyme activity
- Temperature: optimal temp is where the greatest amount of collisions occurs. Up temp, up reaction rate. At high temp enzymes will denature (change shape).
- pH: optimal pH between 6-8, a pH above or below will cause denature
Factors affecting enzyme activity
- Substrate concentration: as substrate conc. increases enzyme activity increases. True until all active sites are occupied.
- Competitive inhibitors: have a similar shape to substrate and bind to active sight. Prevents enzyme from functioning properly.
Digestive enzymes
Amylase: saliva + pancreatic juice.
Acted on starch. Optimum pH: 7-8
Produces maltase + other disaccharides.
Protease: stomach
Acted on protein. Optimum pH: 1-2
Produces smaller protein chains and amino acids.
Lipase: pancreas ->released into small intestine. Produces glycerol + fatty acids. Optimum pH: 8
