Enzymes Introductory

Question 1

Why is life not considered to be at equilibrium?

Answer 1

Because the network keeps most individual steps away from equilibrium.

Question 2

These have the ability to couple a spontaneous reaction to a non spontaneous one to make the overall reaction spontaneous.

Answer 2

Enzymes

Question 3

These are high energy states formed between the reaction of reactants and products.

Answer 3

Transition states

Question 4

This is required to reach the transition state.

Answer 4

Activation energy

Question 5

How do enzymes catalyse thermodynamically favourable reactions?

Answer 5

By lowering the activation energy

Question 6

By decreasing _______ for _________, enzymes accelerate the ____ and _____ reactions equally.

Answer 6

Activation energy; transition state; forward; reverse

Question 7

These enzymes facilitate the transfer of electrons via REDOX.

Answer 7

Oxidoreductatses

Question 8

These enzymes facilitate the transfer of a functional groups.

Answer 8

Transferases

Question 9

These enzymes facilitate hydrolysis reactions (which involve H2O)

Answer 9

Hydrolases

Question 10

These enzymes facilitate non-hydrolytic breaking of breaking of bonds which do NOT involve H2O.

Answer 10

Lyases

Question 11

These enzymes facilitate the transfer of atoms/groups within a molecule to yield an isomeric form. (essentially changes the stereoisomeric form of a molecule)

Answer 11

Isomerases

Question 12

These enzymes join two molecules together to form a new bond (usually coupled to ATP cleavage which provides an energy source)

Answer 12

Ligases

Question 13

These are non-protein factors that help enzymes catalyse reactions.

Answer 13

Cofactors

Question 14

What are the two classes of cofactor?

Answer 14

Metal ions and coenzymes

Question 15

These are Lewis acids, so they can participate in acid base catalysis. They form coordination compounds with precise geometries to allow good positioning for reactant.

Answer 15

Metal ions

Question 16

What does it mean when a metal ion can form coordination compounds with precise geometries?

Answer 16

It means that they can position a reactant exactly where it needs to be in the reaction.

Question 17

These are small, organic molecules that can function as co-subtrates and carriers of electrons, atoms or functional groups.

Answer 17

Coenzymes

Question 18

What type of co-factor is usually derived from vitamins?

Answer 18

Coenzymes

Question 19

This specific cofactor facilitates glycogen phosphorylase activity. It is covalently linked to a lysine residue - and makes it so that enzyme is good for donating proton to Pi (inorganic phosphate)

Answer 19

Pyridoxal phosphate (PLP)

Question 20

This is when 2 reactions (a spontaneous and non-spontaneous reaction) are added together to make the overall reaction spontaneous.

Answer 20

Enzyme coupling