3 - Enzymes

Question 1

how do enzymes speed up a reaction

Answer 1

by lowering activation energy required to initiate a given reaction

Question 2

enzymes

Answer 2

an organic molecule (carbon based molecules)
typically a protein, that catalyses
(speeds up) specific reactions

Question 3

how do enzymes function

Answer 3

They bind to a molecule called a substrate (the reactant), facilitating a chemical reaction that converts the substrate into a product or products. The product then leaves the enzyme, which remains unchanged and can catalyse further reactions.

Question 4

enzyme-substrate complex

Answer 4

the structure formed when an enzyme and substrate are bound together

Question 5

active site

Answer 5

the part of an
enzyme where the substrate binds

Question 6

biochemical pathway

Answer 6

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

Question 7

denature

Answer 7

 the disruption of
a molecule’s structure by an external factor such as heat
- bonds that create its tertiary and quaternary structures are broken down. Denaturation causes a conformational change in the active site

Question 8

optimum

Answer 8

the point at which for a
given condition (e.g. temperature),
the maximum function of an enzyme occurs

Question 9

how does substrate concentration effect rate of reaction

Answer 9

lower substrate concentration
lower reaction rate and vice versa till saturation point

Question 10

limiting factor

Answer 10

a factor that
prevents the rate of reaction from
increasing

Question 11

enzyme inhibitors are

Answer 11

molecules that bind to an enzyme and prevent it from performing
its function.
When an inhibitor is bound to an enzyme, the enzyme can either no longer
catalyse its specific reaction, or its functioning is greatly reduced.

Question 12

competitive inhibition

Answer 12

the hindrance of an enzyme by blocking the active site and preventing the substrate
from binding

Question 13

non-competitive inhibition 

Answer 13

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

Question 14

reversible inhibition

Answer 14

enzyme inhibition that involves weaker bonds that can be
overcome

Question 15

irreversible inhibition

Answer 15

enzyme inhibition that involves stronger bonds that cannot be
broken

Question 16

biochemical pathways

Answer 16

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

Question 17

cofactor

Answer 17

any organic or
inorganic molecule, such
as a coenzyme or metal ion, that assists enzyme function

Question 18

coenzyme

Answer 18

a non-protein organic
cofactor that assists enzyme function. They release energy and
are recycled during a reaction

Question 19

what occurs in co-enzyme cycling

Answer 19

enzyme remains unchanged
- During the reaction,
the coenzyme binds to the active site, donates energy or molecules
- cannot be
immediately reused
- After the reaction
- the coenzyme leaves the enzyme and is recycled
by accepting more energy, so it can then go on to assist in more reactions.

Question 20

ATP

Answer 20

adenosine triphosphate,
a high energy molecule that, when broken down, provides energy for
cellular processes

Question 21

ADP

Answer 21

adenosine diphosphate,
the unloaded form of ATP

Question 22

The conversion of ADP to ATP is a ____
reaction, whilst ATP turns into ADP via a ______ reaction.

Answer 22

phosphorylation (adding phosphate)

dephosphorylation
(removing phosphate)