Ch 3 Enzymes Flashcards
(29 cards)
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.
reactant
A molecule that undergoes a transformation into a product. When enzymes are involved, the reactant is called a substrate.
substrate
The reactant of a reaction catalysed by an enzyme.
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 substrate are bound together.
conformational change
A change in the three-dimensional 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. Also known as a metabolic pathway.
denature
The disruption of a molecule’s structure by an external factor such as heat.
optimal
The point at which for a given condition (e.g. temperature), the maximum function of an enzyme occurs. Also known as optimum.
conformational change
A change in the three-dimensional shape of macromolecules such as proteins.
limiting factor
A factor that prevents the rate of reaction from increasing.
saturation point
The point at which a substance (e.g. an enzyme) cannot receive more of another substance (e.g. a substrate).
limiting reagent
A reactant that prevents the rate of reaction from increasing.
competitive inhibition
The hindrance of an enzyme by blocking the active site and preventing the substrate
from binding.
enzyme inhibitor
A molecule that binds to and prevents an enzyme from functioning.
allosteric site
A region on an enzyme that is not the active site.
non-competitive inhibition
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.
reversible inhibition
Enzyme inhibition that involves weaker bonds that can be overcome.
biochemical pathway
A series of enzyme-catalysed biochemical reactions in which the product of one reaction becomes the substrate of the next reaction. Also known as a metabolic pathway.
