Enzymes V2

Question 1

why are enzymes important?

Answer 1

they are globular proteins that interact with substrate molecules causing them to react at a faster rate.

Question 2

role of enzymes in reactions?

Answer 2

anabolic chemical reaction is catalysed by enzymes
catabolic chemical reaction is catalysed by enzymes
temp, pressure and ph have an effect on rate of reaction

Question 3

Mechanism of enzyme action?

Answer 3

when high temp and pressures are applied the speed of molecules will increase creating more successful collisions.

Question 4

specificity of the enzyme?

Answer 4

many different enzymes are produced by the living organism, each enzyme catalyses one biochemical reaction if which there are thousands in any given cell

Question 5

Lock and key hypothesis?

Answer 5

when substrate is bound to the active site an enzyme - substrate complex is formed. substrate then reacts creating an enzyme-product complex. products then released.

Question 6

how is substrate held in lock and key hypothesis?

Answer 6

r groups within the active site of the enzyme will interact with the substrate forming temporary bonds. strain on these bonds help the reaction

Question 7

induced fit hypothesis?

Answer 7

active site of the enzyme changes slightly as the substrate enters.
initial reaction between the two is weak but interactions rapidly induce changes in the enzymes tertiary structure that strengthen binding, straining the substrate molecule - low activation energy

Question 8

intracellular enzymes?

Answer 8

essential role in the structure and the function of the cells and whole organisms.
enzymes that act with cells

Question 9

extracellular enzymes?

Answer 9

work outside the cell that made them.

Question 10

factors affecting enzyme activity?

Answer 10

temperature
pH
substrate concentration
enzyme concentration

Question 11

pH , how does it affect enzyme activity?

Answer 11

hydrogen bonds and ionic bonds between amino acid r groups hold proteins in their precise three dimensional shape.
hydrogen ions interact with charged r groups.
more hydrogen ions = less r groups able to interact

Question 12

competitive inhibition?

Answer 12

a molecule or part of one that has a similar shape to a substrate can fit onto the active site.
it blocks the substrate from binding by occupying the active site preventing enzyme from catalysing the reaction

Question 13

examples of competitive inhibition?

Answer 13

reversible - statins

irreversible - apsirin

Question 14

non competitive inhibition?

Answer 14

inhibitor binds to enzyme at location other than the active site called the allosteric site.
binding of inhibitor causes the tertiary structure to change, meaning active site changes shape.

Question 15

examples of non competitive inhibitors?

Answer 15

protein pump inhibitors (PPIs) , block enzyme system from secreting hydrogen ions into the stomach

Question 16

end product inhibitor?

Answer 16

product of a reaction acts as an inhibitor to the enzyme that produced it.
excess products are not made and resources not wasted.

Question 17

cofactors?

Answer 17

help enzymes as biological catalysts.
transfer atoms or groups from one reaction to another in multi step pathway or may form part of the active site of an enzyme.
if cofactor is organic it is a coenzyme