Enzyme Test Flashcards
What are enzymes
Special proteins that control chemical reactions in living systems
Biological catalysts
Allow reactions to occur with less activation energy
How do enzymes work?
Use a lock and key mechanism
Enzymes are substrate specific
Are not consumed and can be reused
What are two types of reactions
Catabolic
Anabolic
What is a catabolic
Breakdown
Large molecules broken into smaller molecules
Usually exothermic
What does exothermic mean
Release energy
What does Anabolic do
Building
Small molecules are combined
Usually endothermic
What does endothermic mean
Brings in energy
What is metabolism
Sum of energy related reactions in a living system
In humans metabolism overall produces heat
What is Thyroxin
A hormone from the thyroid gland that is used to regulate overall metabolism
What is iodine
Required to make Thyroxin
What are 4 factors that affect enzyme activity
1) temperature
2) pH
3) Concentration
4) Inhibitors
At what temperature does enzymes do their thing
0-38 enzyme activity increases with temperature as the molecules are moving faster with more energy
38-40 maximum temp for enzyme activity
44+ protein enzymes begins to denature
pH
Each enzyme has a specific pH where it works best (optimum)
Most enzymes work over a narrow range of pH
Small changes in pH can denature enzyme
What are buffers
Used to maintain a constant pH
Concentration
More enzyme=more reactions (unlimited substrate)=straight line upwards
Substrate
Adding substrate increases enzyme activity
At Saturation Point all enzymes are working at maximum rate (graph levels off)
What is Saturation Point
All enzyme molecules are working at maximum speed so adding more substrate makes no difference
Inhibitors
Only found in organic chemistry
On and off switches
Molecules that prevent substrate joining with the enzyme at the active site
What are the 3 types of inhibitors
1) competitive
2) noncompetitive
3) reversible
Competitive
Join to active site and block the substrate
Noncompetitive
Inhibitor attaches to a different part of the enzyme (not the active site)
Reversible
Does not attach permanently to enzyme
Enzyme function is slowed down not stopped
Often used in living systems
Product of a reaction often act as inhibitors
Negative feedback
What does Negative Feedback when talking about Reversible Inhibitors
Keeps level of product constant
What are metabolic pathways
Most enzymes do not work alone
Enzymes work together in sequence the product of one reaction becomes the substrate of the next
