Unit 2.4-Enzymes Flashcards
What types of reactions do enzymes help with?
- Catabolic reactions
- Anabolic reactions
Catabolic reactions definition:
Molecules are broken down into smaller ones and release energy
Anabolic reactions definition:
Energy is used to synthesize larger molecules from smaller ones
What are examples of extra cellular enzymes?
- Fungi
- Digestive enzymes
- Amalayse - turns starch into maltose
- Trypsin - made in the pancreas, turns proteins into smaller polypeptides. The optimum PH is 7.5 - 8.5
Cofactors definition:
A substance that has to be present to ensure that an enzyme catalyzed reaction takes place at the appropriate rate
What are the opposite to cofactors?
Inhibitors
What does the graph for temperature and rate of reaction look like?
Upside down U
How does temperature affect the rate of reaction of enzymes?
When temperature increases, rate of reaction increases because the enzymes and substrates have more kinetic energy so move around faster, so there are more successful collisions
What happens after the optimum temperature for enzyme reactions is met?
The enzyme is denatured and the active site changes shape because the particles are changing position and moving apart, causing the active site to change shape.
What does the graph for PH and rate of reaction look like?
Upside down U but skinny
What is a buffer?
It resists changes in PH by donating or accepting H+ or OH- ions
What type of ions do acids have?
H+
What type of ions do alkalines have?
OH-
What happens to rate of reaction with enzymes when there is not much change from the optimum PH?
Hydrogen or ionic bonds can be restored when PH is restored, so the rate of reaction can increase up to the maximum
What happens to rate of reaction with enzymes when there is a lot of change from the optimum PH?
The bonding changes and the tertiary structure and active site are completely changed so the enzyme is denatured.
What does the graph for substrate concentration and rate of reaction look like?
Increases then plateaus
How does substrate concentration affect the rate of reaction?
Increased substrate concentration causes increased rate of reaction up to a point. After that, the concentration of substrates is no longer the limiting factor, something else is.
What do competitive inhibitors do?
Block the active site by fitting into it
What do non-competitive inhibitors do?
Bind to the enzyme (not in the active site) and change its tertiary structure so a substrate can’t fit into the active site
What does the graph look like for non-competitive inhibitors and rate of reaction?
The line goes up then plateaus but is much lower than it would be without the inhibitors
What does the graph look like for competitive inhibitors and rate of reaction?
The original line goes up then plateaus. The inhibitors line cuts across the bend, so is slightly lower
