Enzyme Graphs

Question 1

In enzyme concentration graphs, why does the graph level off?

Answer 1

Substrate becomes limiting factor
not all enzyme molecules can find substrate

Question 2

In substrate concentration graphs, why does the graph level off?

Answer 2

all enzymes have active site engaged
enzyme is saturated
maximum rate of reaction

Question 3

What is the optimal temperature for most enzymes

Answer 3

37C
35-40*C

Question 4

What is the optimal temperature range for thermophilic enzymes such as Taq Polymerase?

Answer 4

60-80*C

Question 5

What is the optimal pH for pepsin?

Answer 5

2-3-stomach enzyme

Question 6

what is the optimal pH for Trypsin

Answer 6

8- SI enzyme

Question 7

How do changes in pH affect rate of reaction?

Answer 7

adds or remove H+
disrupts bonds, disrupts 3D shape
disrupts attractions between charged amino acids
affect 2° & 3° structure
denatures protein

Question 8

How do salinity levels affect enzymes?

Answer 8

adds or removes cations (+) & anions (–)
disrupts bonds, disrupts 3D shape
disrupts attractions between charged amino acids
affect 2° & 3° structure
denatures protein

Salt is Na+

Question 9

Examples of competitive inhibitors

Answer 9

penicillin- blocks enzyme bacteria use to build cell walls

disulfiram (Antabuse)
treats chronic alcoholism

Question 10

How does the Km of a control graph compare to the competitive inhibitor graph?

Answer 10

high due to the competitive inhibitor blocking the active site so the substrate concentration has to increase in order to go to the active site

Question 11

How does the Vmax of a control graph compare to the competitive inhibitor graph?

Answer 11

Same because both reach it to the maximum rate as substrate concentration increases

Question 12

How does the Km of a control graph compare to the noncompetitive inhibitor graph?

Answer 12

same because active site is not directly affected by the inhibitor; enzyme is just as good for finding the substrate- the only issue is the active site getting deactivated

Question 13

How does the vmax of a control graph compare to the noncompetitive inhibitor graph?

Answer 13

Lower- functional enzymes; some enzymes are unusable due to the inhibitors

Question 14

Examples of non-competitve inhibitors

Answer 14

some anti-cancer drugs
inhibit enzymes involved in DNA synthesis
stop DNA production
stop division of more cancer cells

cyanide poisoning
irreversible inhibitor of Cytochrome C,
an enzyme in cellular respiration
stops production of ATP

Question 15

When is delta G negative?

Answer 15

for spontaneous, exergonic reaction
releasing energy
product has less energy compared to reactant energy
product- reactant

Question 16

When is delta G positive?

Answer 16

nonspontaneous, endergonic reaction;
energy absorbing
product has more energy compared to reactant energy

Question 17

Do enzymes affect Delta G

Answer 17

no