Enzymes Flashcards
Enzyme
An organic molecule, typically a protein, that catalyses (speeds up) specific reactions.
Catalyst
A substance capable of increasing the rate of a reaction without being used up.
Catalyse
To increase the rate of a reaction
Substrate
The reactant of a reaction catalysed by an enzyme.
Reactant
A molecule that undergoes a transformation into a product. When enzymes are involved, the reactant is called a substrate.
Product
The transformed molecule created in a reaction.
Active site
The part of an enzyme where the substrate binds
Enzyme-substrate complex
The structure formed when an enzyme and a substrate are bound together.
Conformational change
A change in the 3D shape of macromolecules such as proteins.
Activation energy
The energy required to initiate a reaction.
Collision theory
Explanation of chemical reactions that states that in order to react molecules must hit one another.
Biochemical pathway
A series of enzyme-catalysed biochemical reactions in which the product of one reaction becomes the substrate of the next reaction. AKA metabolic pathway
Optimal
The point at which for a given condition (e.g. temperature), the maximum function of an enzyme occurs. AKA optimum
Denature
The disruption of a molecule’s structure by an external factor such as heat.
Saturation point
The point at which a substance (e.g. an enzyme) cannot receive more of another substance (e.g. a substrate).
Limiting factor
A factor that prevents the rate of reaction from increasing.
Limiting reagent
A reactant that prevents the rate of reaction from increasing.
Enzyme inhibitor
A molecule that binds to and prevents an enzyme from functioning.
Competitive inhibition
The hindrance of an enzyme by blocking the active site and preventing the substrate from binding.
Non-competitive inhibitor
The hindrance of an enzyme by binding to an allosteric site and changing the shape of the active site to prevent the substrate from binding.
Allosteric site
A region on an enzyme that is not the active site.
Reversible inhibition
Enzyme inhibition that involves weaker bonds that can be overcome.
Irreversible inhibition
Enzyme inhibition that involves stronger bonds that cannot be broken.
Cofactor
Any organic or inorganic molecule, such as a coenzyme or metal ion, that assists enzyme function.
Coenzyme
A non-protein organic cofactor that assists enzyme function. They release energy and are recycled during a reaction.
ATP - adenosine triphosphate
A high energy molecule that, when broken down, provides energy for cellular processes.
ADP - adenosine diphosphate
The unloaded form of ATP.
