Enzymes Definitions Flashcards
(24 cards)
activation energy
The amount of energy needed for a reaction to happen.
active site
A specific region on an enzyme where the substrate binds and the reaction
takes place.
amylase
An enzyme that catalyses the extracellular breakdown of starch.
catalase
An enzyme that catalyses the intracellular breakdown of hydrogen peroxide into
oxygen and water.
coenzyme
A type of cofactor that is bound loosely to an enzyme with weak interactions.
cofactor
A non-protein molecule that is needed for the effective functioning of an enzyme.
competitive inhibitor
A molecule which binds to the active site of an enzyme and prevents the substrate from binding.
cyanide (CN-)
A metabolic poison which acts as an irreversible inhibitor of cytochrome
oxidase and hence preventing respiration.
end-product inhibition
A method of enzyme inhibition where the product of an enzyme controlled reaction can bind to the enzyme and prevent it from working.
end-product inhibition
A method of enzyme inhibition where the product of an enzyme controlled reaction can bind to the enzyme and prevent it from working.
enzyme
A biological catalyst used to speed up the rate of biochemical reactions without
being used up or permanently altered.
enzyme-product complex
The temporary complex formed after the enzyme has catalysed the reaction but before the products have left the active site of the enzyme.
enzyme-substrate complex
The temporary complex formed when the substrate binds to the active site of the enzyme.
extracellular reaction
A reaction that occurs outside of cells.
inactive precurser
An inactive form of an enzyme that cannot carry out its function until it is
activated.
induced fit hypothesis
A model of enzyme action that describes how once a specific substrate binds to the active site, the enzyme undergoes subtle conformational changes to fit the substrate better.
intracellular reaction
A reaction that occurs within cells.
lock and key hypothesis
A model of enzyme action that describes how the enzyme will only fit a substrate that has the correct complementary shape to the active site.
metabolism
The sum of all the chemical reactions taking place in a cell.
non-competitive inhibitor
An inhibitor which binds to a different part of an enzyme known as the allosteric site and prevents the enzyme from functioning.
prosthetic group
A type of cofactor that is bound tightly to an enzyme with strong interactions.
prosthetic group
A type of cofactor that is bound tightly to an enzyme with strong interactions.
substrate specificity
The ability of an enzyme to catalyse only a specific reaction or set of reactions which have substrates complementary to the active site of the enzyme.
trypsin
An enzyme that catalyses the extracellular breakdown of proteins.
