Unit 1 (1.4) Flashcards
Enzymes
What is metabolism
The sum of all the enzyme controlled chemical reactions taking place in a cell
What are the two types of reactions that make up a metabolism
Anabolic and Catabolic reactions
What is anabolism?
A set of metabolic pathways that synthesise complex molecules from smaller, simpler molecules
What is catabolism?
A set of of metabolic pathways that breakdown complex molecules into smaller, simpler molecules
What is an enzyme?
A biological catalyst used to speed up the rate of rate of intra and extracellular biochemical reactions
Not used up of permanently altered
What is an intracellular enzyme?
An enzyme that acts within cells. eg catalase
What is an extracellular enzyme?
An enzyme that is secreted by cells and functions outside of cells. eg amylase
What is the active site of an enzyme?
Region on enzyme that is complementary to the shape of a specific substrate, it binds and the reaction takes place.
Why is an active site describes as specific?
The 3D structure of each enzyme including active site is unique due to the presence of different side branches and chains
Only specific substrates complementary to the active site can bind
What is activation energy?
The minimum amount of energy required for a reaction to take place.
What is a catalyst?
Lowers the activation energy of the reaction
An increase in the rate of a chemical reaction using a catalyst
What is the induced fit hypothesis?
A model of enzyme action which states that:
Once a specific substrate binds to the active site, the enzyme undergoes subtle conformational changes. Putting a strain on the substrate, lowering the activation energy for the reaction.
What factors affect the rate of an enzyme controlled reaction?
Temperature
pH
Substrate concentration
What is a buffer
A molecule that maintains a constant pH in a solution when small amounts of acid or base are added
What is a competitive inhibitor
A molecule which binds to the active site of an enzyme, blocking it and preventing and preventing the substrate from binding.
Is competitive inhibition temporary or permanent?
Competitive inhibition in generally temporary . However in some cases eg. aspirin it may be permanent
How does increasing substrate concentration affect competitive inhibition?
Increases substrate concentration
More substrate than inhibitor
Rate of reaction increases
What is a non-competitive inhibitor
An inhibitor which binds to a different part of an enzyme the allosteric site
The tertiary structure of the enzyme including the active site changes shape
Active site is no longer complementary to the substrate
The substrate cannot bind and the enzyme is inhibited
Is non-competitive inhibition temporary or permanent?
Permanent
How does increasing substrate concentration affect non-competitive inhibition?
Increasing the substrate concentration will not overcome the effect of the non-competitive inhibitor
What are immobilised enzymes?
Enzymes that attached to to an inert, insoluble material over which the substrate passes and the reaction takes place
Example of application of immobilised enzymes?
Biosensors
Why are immobilised enzymes important in industrial processes?
Enables enzymes to be reused
Improves enzymes stability in variable/extreme temperatures and pH
Increases the efficiency of reactions
