Factors Affecting Enzymes Flashcards
What does an enzyme need in order for it to work?
- Contact with a substrate/substrates.
- Have an active site which fits a substrate.
What is the effect of temperature?
A rise in energy increases the kinetic energy of molecules, so molecules move around more rapidly and collide more often with other molecules.
What Is the effect of temperature on enzyme action?
More effective collisions result in more enzyme-substrate complexes being formed so the rate of reaction increases.
What is denaturation?
Denaturation is a permanent change, and once it occurs, the enzyme can not function again.
What happens when an enzyme is denatured?
An enzyme is so disrupted, e.g. hydrogen bonds start to break, it stops working.
How does a change in pH effect the enzyme?
Alters charges on the amino acids that make up the enzymes active site. Substrate can no longer become attached to enzyme, and so enzyme-substrate complexes can no longer form.
How does a change in pH cause the active site to change shape?
The bonds maintaining enzyme’s tertiary structure may break, causing the active site to change shape.
Why is it significant that enzymes don’t change after acting on a substrate?
Enzymes can repeat the procedure on substrates a number of times. They are not used up and therefore work effectively at low concentration.
What does the initial proportionate increase on the enzyme concentration graph show?
There is more substrate than enzyme’s active sites can cope with, so as enzyme concentration increases, so will the rate of reaction as more substrates can be acted on at one time.
What does the levelling off on the enzyme concentration graph show?
The rate of reaction has stabilised at a constant level as all the substrate molecules can occupy an active site at any one time. The addition of further enzyme molecules has no effect as there is already enough active sites to accommodate all substrates.
What does the initial proportionate increase on the substrate concentration graph show?
The rate of reaction is not at the maximum possible for the number of enzymes there are, so as substrate concentration is increased, rate of reaction will speed up as they are occupying all enzymes active sites.
What does the levelling off on the substrate concentration graph show?
There are enough substrates to fill all the enzymes active sites, so the rate of reaction is at its maximum. The addition of substrate molecules will have no effect as all enzyme active sites are occupied.
