BIOLOGY | Unit 3 AOS 2: Biochemical pathways Flashcards
Biology
Anabolic reactions
- Building up molecules
- Needs energy
- Endothermic
Catabolic reactions
- Breaking down molecules
- Releases energy
- Exothermic
Why are enzymes beneficial to cells?
1) They speed up biochemical reactions.
2) They lower activation energy.
Active site
Where the substrate binds to the enzyme. It orientates the substrate into the correct position for the reaction to take place.
Where does the substrate bind?
The active site of the enzyme.
Substrate
The molecule that an enzyme binds to.
Product
The final molecule made by the enzyme.
3 factors that effect enzyme function?
1) temperature
2) pH
3) concentration
Optimal temperature
The temperature at which the enzyme works best.
Denaturation
Occurs when enzymes are moved out of their optimum range. It is irreversible and causes the bonds holding the enzymes together to break, causing a change in protein structure/shape.
What happens when the proteins are heated past their optimal temperature?
They undergo denaturation.
What happens when proteins are at a temperature too low?
Enzymes slow down and stop functioning (this is reversible and not denaturation)
What is the effect of pH?
Changes in pH can alter a protein’s shape, especially its active site, affecting its function. Each enzyme has an optimal pH range, and if it moves outside this range, the enzyme can denature and lose its ability to work.
What are enzymes?
Organic catalysts that often influence entire biochemical pathways.
Competitive inhibitor
Able to bind to the enzyme at the active site but doesn’t trigger a reaction. This blocks the substrate from being able to bind to the active site.
Non-competitor inhibitor
Will bind to the enzyme at the allosteric site (site other than active site) which causes the shape of the enzyme to change so the substrate can no longer fit.
Reversible inhibitors
Form weak bonds with enzymes which can break. They slow but don’t stop the rate of reaction.
Irreversible inhibitors
Form strong bonds with enzymes, resulting in that enzyme being unable to catalyse reactions indefinitely. These are mostly competitive inhibitors.
Are non-competitive inhibitors affected by substrate concentration?
No.
How are competitive inhibitors overcome?
By increasing the substrate concentration.
What is photosynthesis?
The process of synthesising glucose from carbon dioxide and water in the presence of sunlight.
Why is photosynthesis a biochemical pathway?
- A series of reactions
- Catalysed by enzymes and typically involves coenzymes
- The reactions can take place in different cellular locations
- Outputs if one reaction can be inputs for another reaction
Coenzymes
Non-protein molecules that assist enzyme function. They are cycles in reactions by being built up in one reaction and broken down in another.
What does ADP + Pi create?
ATP
