Catalysis, Enzymes and Michaelus Menton

Question 1

Enzymes Def

Answer 1

Biological catalysts that alter the rate of reactions without being used up themselves. Essential for life as they allow reactions to occur at necessary speeds that would be impossible to achieve at body temp. Specific to 1 substrate, globular, 3D shape

Question 2

Catalyst Def

Answer 2

Increases rate of reaction (decreases activation energy) without being used up itself. Decreaing activation energy means a greater number of collision will be effective

Question 3

Factors effecting enzymes

Answer 3

Substrate conc, temp and pH

Question 4

Enzymes as biological catalysts outline

Answer 4

Active site’s functional groups bond breaking (catabolic) and bond making (anabolic) reactions. Placement of functional (prosthetic) groups is a result of enzymes folding (secondary, tertiary, ect)

Question 5

Chiral Def

Answer 5

Molecule is not identical to it’s mirror image due to assymetrical C (different substituents on either side). Posses different qualities then each other

Question 6

Enzymes chirality Outline

Answer 6

1 enantiomer may be able to interact more due to more points for contact

Question 7

Enzyme substrate lock-key theory

Answer 7

Enzyme active site = lock (defined, set structure) substrate = key. Only substrate that fits perfectly into enzymes active site will have it activation energy lower (by having stress put on bonds). When product is made it no longer fits active site and leaves. Active site never changes shape

Question 8

Enzyme-substrate complex Induced Fit Theory

Answer 8

Due to flexible nature of proteins (weak intermolecular bonds disrupted by enviormental cahnges), active site moves slightly to better fit substrate. Substare must still be complementary however

Question 9

Effect of temp on enzymes

Answer 9

Increasing temp = increased reaction rate. Until a point is reached. After point increasing temp = braking of salt bridges and hydrophobic interactions = denaturing of protein

Question 10

Effect of increasing pH on enzymes

Answer 10

Donation of a H+ from the NH3^+ group. Neutralizing protein, breaking salt bridge bonds

Question 11

Effect of decreasing pH on enzymes

Answer 11

Adding of H+ to COO- group. Neutralising protein, breaking salt bridge bonds

Question 12

Enzyme optimum pH

Answer 12

pH at which the folded protein structure is most stable

Question 13

Michaleus Menton assumption

Answer 13

1 enzyme : 1 substrate

Question 14

Low substrate conc: rate and conc

Answer 14

1st order. rate is proportional to substrate conc

Question 15

High substrate conc: rate and conc

Answer 15

. 0 order. Rate is independent of substrate conc

Question 16

V max

Answer 16

Fastest rate of enzyme. most product produced per time

Question 17

Km

Answer 17

Substrate Conc at half Vmax. Indication of substrate affinity. Lower Km = higher affinity (less needed to get to Vmax)

Question 18

2 fates of enzyme substrate complex

Answer 18

Dissociates into substrate and free nezyme or dissociates into producy and free enzymes

Question 19

Rate Constant 1 (k1) Outline

Answer 19

Rate constant when enzyme and substrate form enzyme substrate complex

Question 20

Rate Constant 2 (k2) Outline

Answer 20

Rate constant when enzyme substrate complex dissociates into substrate and free enzyme

Question 21

Rate constant 3 (k3) Outline

Answer 21

Rate constant when enzyme substrate complex dissociates into substrate and free enzyme

Question 22

How to calculate Km (Michalus Menten Constant) from rate constants

Answer 22

(k2 + k3)/ k1

Question 23

Michaelius Menten rate equation

Answer 23

rate = ( (Vmax)([substrate conc])/ (Km + substrate conc)

Question 24

Rate equation at low substrate conc (1st order reaction)

Answer 24

(Vmax x [substrate conc])/ Km

Question 25

Rate equation at high substrate conc (0 order reaction)

Answer 25

(Vmax x [substrate conc])/ [Substrate conc]