Enzymes Flashcards

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1
Q

structure of enzymes

A

attach to substrates by the active site, active sites are specific, the 3D shape of enzymes allows them to also be specific

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2
Q

are enzymes reactants

A

no as they are not destroyed or used up during a chemical reaction

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3
Q

function of enzymes

A

catalysts in chemical reactions, the work by lowering the activation energy required by a cell therefore increasing reaction rate

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4
Q

two ways enzymes can attach to substrates

A

induced fit model theory, lock and key model theory

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5
Q

induced fit model theory

A

enzymes alter their shape to fit the substrate, the active site continues to change until the substrate is completeley bound to it, only then will the final shaoe and charge be determined

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6
Q

lock and key model theory

A

the shape of the substrate exactly matches/is complementary to the active site of the enzymes, no change is necessary from the active site or substrate in order to bind together

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7
Q

when is an enzyme considered denatured

A

when the active site is altered to the point it can no longer attach to the substrate, therefore a denatured enzyme cannot catalyse a reaction, it cannot be restored to its original shape, denaturation is permanenet

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8
Q

what causes an enzyme to denature

A

changes in temps and pH’s of the enzymes environment

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9
Q

for enzymes, what affects rate of reaction

A

temp, pH, concentration of enzymes, concentration of substrates, inhibitors, cofactors and coenzymes

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10
Q

how does concentration of enzymes and substrates affect rate of reaction

A

more enzymes and more substrates= more collisions so moree reactions, the increase will only continue if there is an enzyme/substrate supply that is endless, if not point of saturation is reached

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11
Q

types of inhibitors

A

competitive, non-competitive, irreversable, reversible

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12
Q

irreversible inhibitors

A

bind to enzyme with strong covalent bonds that chhange the protein chemically which cant be reversed

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13
Q

inhibitors

A

substances that bind to the enzyme and stop it from working to its full capacity

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14
Q

reversible inhibitors

A

bind non-covalently to enzymes, non covalent bonds are easily broken therefore seperating the inhibitor and enzyme which can then continue catalysing as normal

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15
Q

competitive inhibitors

A

have a similar shape yo tthe substrate so bind to the active site, making it difficult for the substrate to bind to the active site, they don’t change the active site and can be removed by increasing substrate concentration

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16
Q

non-competitive inhibitors

A

bind to part of the 3D shape which is not the active site, instead it is the allosteric site, this changes the 3D shape of the protein including the active site, decreasint the enzymes catalysing ability, increase substrate concentration has no affect

17
Q

why does end product inhibition occur

A

in many biochemical pathways, the end product becomes the substrate of the next reaction, when enough of the substrate is produced, the cell no longer needs to produce that substrate

18
Q

what is end product inhibition

A

when a biochemical pathway is shut down, this occurs when the substrate attaches to the first enzyme of the pathway ar is allosteric site, causing it to be ineffective, shutting down the pathway

19
Q

how does atp act as a coenzyme

A

atp attaches to the active site of the enzyme, giving energy required for the reaction to take place, it loses one phosphate atom in tthe process, then leaaves the enzyme where the enzyme can be replaced with another atp

20
Q

how does NADH and NADPH act as a cofactor

A

attaches to the active site, provides energy for reaction, loses hydrogen atom in the process which changes it shape, leaves the enzyme to become loaded again