5. Enzymes Flashcards
Catalyst?
A substance which increases the rate of a chemical reaction without being used up or changed itself
Enzymes?
BIOLOGICAL Catalyst that speeds up the rate of metabolic reactions.
(biological because they are made in living cells, catalysts because they speed up the rate of chemical reactions without being changed)
Are proteins
Structure of Enzymes
Enzymes are proteins that contain a highly specific active site that fits a specific substrate
Enzyme Specificity
Enzymes are specific to one particular substrate(s) as the active site of the enzyme, where the substrate attaches, is a complementary shape to the substrate
This is because the enzyme is a protein and has a specific 3-D shape
This is known as the lock and key hypothesis
When the substrate moves into the enzyme’s active site they become known as the enzyme-substrate complex
After the reaction has occurred, the products leave the enzyme’s active site as they no longer fit it and it is free to take up another substrate
https://www.savemyexams.co.uk/notes/igcse-biology-cie-new/5-enzymes/5-1-how-enzymes-work/
4 factors affecting rate of enzyme controlled reaction?
SET pH
Subtance Concentration,
Enzyme Concentration,
Temperature
pH
Effect of Temperature
Temperature increases - Rate of reaction increases.
After Optimum Temperature - Rate of Reaction decreases
Why does rate of reaction increases when temperature increases?
- More kinetic energy for particles when heated.
2. Increase in possibility of collision
Temperature above optimum?
Active site gets distorted as the enzyme denatures and , no longer can fit substrate.
Effect of pH?
Rate of reaction is fastest at Optimum pH. After that reduces.
Amylase
is an enzyme that digests starch (a polysaccharide of glucose) into maltose (a disaccharide of glucose).
