Enzymes and Digestion Flashcards
Definition of an enzyme
An enzyme is a protein that speeds up the rate of a chemical reaction without being used up (biological catalyst)
How do enzymes function
They have a part called the active site which is complementary in shape for the raw material to fit into. In the active site the raw material is broken down to make a product. The raw material is called the substrate.
What conditions are required
They work best at 37 degrees and usually work best at PH7 which is the optimum.
What is the lock and key theory
Each enzyme active site only fits one type of substrate. The enzyme active site is complementary for the substrate to fit into.
What factors affect enzymes
PH and temperature.
How does Ph and temperature affect enzyme activity
At other PH and temps the enzymes become denatured. So the rate of reaction decreases dramatically
What does it mean when an enzyme becomes denatured
Means the substrate will no longer fit into the active site so no reaction can occur.
What is an inhibitor
A molecule that fits loosely or partially into the active site but are not broken down
How do inhibitors affect enzyme rate of reaction
Rate of reaction decreases as inhibitors block the substrate from binding to the active site
What is the method for the effect of temperature on enzyme activity
- Put 5ml of amylase into a boiling tube and place in a water bath at 0 degrees for 5 minutes
- Put 2 drops of iodine into each section of a spotting tile
- Put 10ml of starch into a small beaker
- Add the starch to the amylase then immediately take a drop from the solution and add to the spotting tile
5.Test every 30 seconds until the iodine no longer turns blue/black or until 8 minutes is up. Record time taken for the iodine to turn blue/black - Repeat this exp at 25,40,60 and 80 degrees
Explain the changes to enzyme reactivity with low temperatures
At low temperatures there is less kinetic energy meaning less collisions between the substrate and enzyme, therefore less enzyme substrate complexes formed and a slower rate of reaction
Method for the effect of pH on enzyme activity
- Put 2 drops of iodine into each section of a spotting tile
- Put 5ml of starch into a small beaker and add 2ml of buffer of pH4,pH7 or pH10
- Add 5ml of amylase
- Immediately take a drop from the solution and add to the spotting tile
5.Test every 30seconds until the iodine no longer turns blue/black or until 8 minutes is up - Record time taken for iodine to no longer turn blue/black
- Repeat this experiment using the other PH buffers
What is the dependent variable for the effect of pH on enzyme activity
How much time it takes starch to be digested/ minutes
What does optimum mean
The maximum rate of enzyme activity
Name a commercial use of enzymes and how they are used
Biological washing powder, contains enzymes for breaking down difficult to remove stains. These enzymes are thermostable and break down large, complex, insoluble stains into small soluble molecules that dissolve into water.
