Chapter 2 Enzymes

Question 1

What factors can cause denaturation?

Answer 1

Temperature, pH, Salinity,

Question 2

What is the optimal pH for stomach enzymes?

Answer 2

2

Question 3

What is the optimal pH for the small intestine?

Answer 3

8.5

Question 4

What is the optimal ph in the blood?

Answer 4

7.4

Question 5

Oxidoreductase

Answer 5

Catalyzes oxidation reduction reactions

Question 6

Transferase

Answer 6

Moose functional groups from one molecule to another

Question 7

Lyase

Answer 7

Cleaves molecule into two molecules

Synthase joins 2 molecules into 1

Question 8

Hydrolase

Answer 8

Cleaves one molecule into two molecules by adding a water molecule.

Question 9

Isomerase

Answer 9

Rearranges the bonds within a molecule. Creates isomers

Question 10

Ligase

Answer 10

Catalyzes addition/synthesis of larger molecules

Question 11

What is Km

Answer 11

Substrate concentration at half remarks or when half the active sites are full

Question 12

What is Vmax?

Answer 12

When the enzyme works at maximum velocity

Question 13

What does a high km represent?

Answer 13

Low affinity

Question 14

What does a low km represent?

Answer 14

High affinity

Question 15

Kcat

Answer 15

Number of substrate molecules converted to products/turned over

Question 16

What does a hills coefficient of greater than one represent?

Answer 16

Positive Cooperative binding

Question 17

What does a hills coefficient of less than one represent?

Answer 17

Negative cooperative bonding

Question 18

What does a hills coefficient equal to one represent?

Answer 18

No cooperative bonding

Question 19

What is a cofactor/coenzyme?

Answer 19

Non-protein molecule that helps participate in the catalyst of a reaction. They bind to the active site of the enzyme.

Question 20

Apoenzyme

Answer 20

Enzyme with no cofactor

Question 21

Holoenzyme

Answer 21

Enzyme with cofactor

Question 22

Competitive Inhibitor

Answer 22

Km- Increases
Vmax- Unchanged

Can increase substrate concentration to overcome inhibitor binding.

Binds at active site

Question 23

Noncompetitive

Answer 23

Km- Unchanged
Vmax- Decreased

Binds at allosteric site

Question 24

Uncompetitive Inhibitor

Answer 24

Both Km and Vmax reduced

Binds at the enzyme substrate complex

Question 25

Mixed Inhibitor

Answer 25

Vmax is always decreased.

Km increased when inhibitor has a higher affinity for the enzyme than the E/E-S complex

Km decreased when when inhibitor has a lower affinity for the enzyme than the E/E-S complex

Binds at either the enzyme or the enzyme substrate complex.

Question 26

What does a positive delta G represent?

Answer 26

Endergonic reaction

Question 26

What does a negative delta G represent?

Answer 26

Exergonic reaction

Question 27

Prosthetic group

Answer 27

Tightly bound cofactor or coenzyme that is necessary for enzyme function is known as a prosthetic group.

Question 28

What are the two types of covalent enzyme modification?

Answer 28

Phosphorylation/Dephosphorylation and Glycosylation

Addition of a phosphate group or covalent assessment of sugar moieties

Question 29

What is the main difference between a coenzyme and a cofactor?

Answer 29

Cofactors are generally inorganic molecules/metal ions ingested in the diet

Coenzymes are small organic groups i.e. vitamins, vitamin derivatives such as NAD+ FAD+ and CoA

Question 30

What types of things do enzymes affect?

Answer 30

Lower activation energy

Increase reaction rate

Do not affect the overall delta G of a reaction

Are not consumed by reaction and do not change in a reaction.

Temperature and pH sensitive

Question 31

What does a hills coefficient that is greater than one less than equal to one mean?

Answer 31

Positive cooperativity negative cooperativity and no cooperativity

Question 32

What is the role of coenzymes and cofactors?

Answer 32

The aid to the stability and efficacy of the enzyme