ENZYMES

Question 1

Enzymes have great specificity, explain

Answer 1

Globular proteins have a very specific shape as a result of their primary secondary, tertiary and quaternary structure. This means that each enzyme will only catalyse a specific reaction

Question 2

what do we call reactions that build up new chemicals

Answer 2

Anabolic

Question 3

what do we call reactions that break down substances

Answer 3

catabolic

Question 3

what do we call a combination of catabolic and anabolic reactions

Answer 3

Metabolic

Question 3

examples of extracellular enzymes

Answer 3

digestive enzymes
lysome-tears

Question 3

state what is meant by an enzyme

Answer 3

proteins that have very specific shape as a result of their primary, secondary tertiary and quaternary structures.

Question 3

identify enzymes that catalyse reactions outside of cells

Answer 3

Extracellular enzymes

Question 3

examples of intracellular enzymes

Answer 3

DNA polymerase
DNA ligase

Question 3

state what is meant by a catalyst

Answer 3

a substance that speeds up reactions without changing the substance being produced or being changed itself

Question 3

define metabolic chain (Metabolic pathway)

Answer 3

a series of linked reactions in the metabolism of a cell

Question 3

identify enzymes that catalyse reactions within the cell

Answer 3

Intracellular enzymes

Question 4

For reactions to take place , reacting molecules must have enough energy to break the chemical bonds that hold them together… what is this energy called?

Answer 4

Activation energy

Question 5

Lock and key hypothesis can be replaced by what theory? outline it

Answer 5

Induced fit hypothesis-the active site still has a distinctive shape but it is flexible. Once the substrate enters the active site, its shape modifies around it to form an active complex.

the enzyme reverts to its inactive and relaxed form until another substrate molecule binds

Question 5

define what is meant by molecular activity/ turnover number

Answer 5

the number of substrate molecules transformed per minute by a single enzyme molecule

Question 6

describe the effect of temperature on enzyme efficacy

Answer 6

Kinetic energy increases, substrate particles move around faster increasing the chances of particles colliding into the active site.
the rate of reaction doubles for every 10 C increase in temp
Low temperatures inactivate the enzyme
Temperatures above the optimum temp may denature the enzyme

Question 7

describe the effect of pH on enzyme efficacy

Answer 7

Changes shape of protein molecules as the charges on the amino acid side chains are affected by hydrogen of hydroxide ions.

Question 8

describe the effect of concentration of enzyme efficacy

Answer 8

As the concentration of a substrate increases if the amount of enzyme stays constant the rate of reaction will increase.

at some point all the enzyme active sites will be working at full capacity , therefore rate of reaction will plateau.

Question 9

state the role of buffers

Answer 9

maintain a constant pH

Question 10

What are enzyme inhibitors

Answer 10

substances that slow down enzymes or stop them from working

Question 11

what is reversible inhibition

Answer 11

inhibition of the action of an enzyme by an inhibitor that does not permanently affect the functioning of the enzyme and can be removed from the enzyme. Often used to control the reaction rates within a cell

Question 12

What is irreversible inhibition

Answer 12

the inhibition of the action of an enzyme that is permanent and cannot be undone. It is never used within cells to control the rate of reaction.

Question 13

what is competitive inhibition

Answer 13

inhibition where the inhibitor molecule is similar in shape to the substrate molecule and competes with it for the active site of the enzyme (affected by both substrate concentration and inhibitor)

Question 14

what is non competitive inhibition

Answer 14

inhibition in which the inhibitor does not compete for the active site but forms a complex with the enzyme or enzyme substrate complex and changes the shape of the active site so it can no longer catalyse the reaction (affected by only the concentration of inhibitor)

Question 15

outline end product inhibition

Answer 15

control system in many metabolic pathways in which an enzyme at the beginning of the pathway is inhibited by one of the end products of the reaction.

Question 16

what do products bind to in end product inhibition

Answer 16

allosteric site of enzyme