Enzymes Flashcards
What is the lock and key hypothesis?
This is when the substrate and active site are completely complimentary to each other.
What is the induced fit hypothesis?
This is when the active site is not initially complimentary but it then moulds around the substrate to make an enzyme substrate complex.
Define anabolism
Anabolism is the chemical reaction where bonds are formed
Define catabolism
Catabolism is the chemical reaction where bonds are broken
Define the activation energy
The amount of energy required to allow for a chemical reaction. The energy is acquired from the surroundings.
What is the difference between the active site in the lock and key vs induced fit theory?
The active site in the lock and key theory is rigid and complimentary vs the induced fit theory active site is flexible and initially not complimentary.
Can enzymes be reused after a reaction?
Yes enzymes can be reused after a reaction if they are not denatured.
What are enzymes?
Enzymes are globular proteins that catalyse a metabolic reaction
What two processes make up metabolic reactions.
Anabolism and catabolism
What gives the enzyme is catalytic ability?
Its tertiary structure
Where does the substrate act on the enzyme?
The active site
Give 4 examples of factors which affect enzyme reactions…
- Temperature
- pH
- Substrate concentration
- Enzyme concentration
How does low temperature affect enzyme activity?
Low temp - less kinetic energy in the molecules, resulting in fewer collisions between the substrate and enzyme active site. Therefore the enzyme is inactive
What happens to the rate of reaction as the temp increases?
Increase in kinetic energy, means an increase in the rate of reaction until it reaches its optimum temperature.
What happens to the rate of reaction as the temp increases?
Increase in kinetic energy, means an increase in the rate of reaction until it reaches its optimum temperature.
Describe what happens to the rate of reaction once the temp is greater than the optimum
rate of reaction decreases, the enzyme has been denatured, the hydrogen and ionic bonds within the tertiary structure are broken which causes the active site to lose its complimentary shape.
How is the rate of an enzyme catalysed reaction measured?
The amount of substrate changed / product formed over a period of time.
At what pH does maximum enzyme activity occur?
optimum pH (this will vary from enzyme to enzyme)
How does pH affect the activity of the enzyme?
Changes to pH will alter the active site of the enzyme
What is pH?
pH is the measurement of hydrogen ion concentration
How does hydrogen concentration affect enzymes?
Hydrogen concentration changes the charge on R groups which alters the amino acids and the ionic bonds are affected
Fill in the blanks:
At non-optimal pH the ____ attaches less readily to the _____
Substrate
enzyme active site