Enzymes

Question 1

What is a catalysis?

Answer 1

Study of how fast chemical reactions proceed

Question 2

What is a catalyst?

Answer 2

A substance that increases the rate of chemical reactions

Question 3

How do catalysts act?

Answer 3

By reducing the activation energy of a chemical reaction

Question 4

What are enzymes?

Answer 4

Proteins which are biochemical catalysts

Question 5

Relative specificity

Answer 5

Acting on several structurally related substances

Question 6

Absolute specificity

Answer 6

Acting on one and only one substance

Question 7

Stereochemical specificity

Answer 7

Acting on a specific stereoisomer

Question 8

What can be regulated?

Answer 8

The catalytic behavior of an enzyme

Question 9

What are coenzymes?

Answer 9

Organic molecules that act as cofactors

Question 10

What are cofactors

Answer 10

Small organic molecules and ions (Zn, Co, Fe)

Question 11

When can enzymes be catalytically active?

Answer 11

Only if a specific group or cofactors is attached to them

Question 12

What makes an active enzyme?

Answer 12

Apoenzyme and cofactor (coenzyme or ion)

Question 13

What is an active site?

Answer 13

Location on an enzyme where a substrate is bound to initiate catalysis

Question 14

When does a binding of a substrate to the active site occur?

Answer 14

By matching intermolecular forces

Question 15

What happens when an enzyme binds to a substrate?

Answer 15

Is forms an enzyme-substrate complex which releases a product

Question 16

What is the lock-and-key model?

Answer 16

When the rigid enzyme and substrate have matching shapes.
Active site + substrate= EXACT FIT

Question 17

What is the induced-fit model?

Answer 17

When the flexible enzyme changes shape to match the substrate.
Active site ADJUSTS to fit substrate

Question 18

What is the enzyme activity?

Answer 18

The rate at which an enzyme catalyzes a reaction.
=speed

Question 19

What is the turnover number?

Answer 19

The number of molecules of substrate acted on by one molecule of enzyme per minute.
=the amount

Question 20

What factors affecting enzyme activity are due to kinetics ?

Answer 20

Enzyme and substrate concentration

Question 21

What factors affecting enzyme activity are affecting the structure of an enzyme?

Answer 21

Temperature and pH

Question 22

Enzyme concentration

Answer 22

Increase the number of enzyme

Question 23

Substrate concentration

Answer 23

Increase substrate, reach max velocity

Question 24

What happens when you increase temperature?

Answer 24

denaturation

Question 25

What is an ezyme inhibitor?

Answer 25

A substance that decreases the rate of an enzyme-catalyzed reaction.

Question 26

What is an irreversible inhibition?

Answer 26

Forms. Strong bond with a specific functional group of an enzyme rendering it inactive. (Kills enzymes)

Question 27

Reversible inhibition

Answer 27

Competitive and in competitive inhibitor

Question 28

Competitive inhibitor

Answer 28

Substrate + inhibitor takes the same spot in the enzyme.

Question 29

How to restore the activity of the enzyme?

Answer 29

By adding more substrate

Question 30

Noncompetitive inhibitor

Answer 30

- Binds to the enzyme at a location other than the active site - cannot be reversed by adding more substrate - often changes the active site of the enzyme

Question 31

Activation of zymogens (proenzymes)

Answer 31

Inactive precursor of an enzyme

Question 32

Why are enzymes released in an inactive form?

Answer 32

To become fully active only when needed

Question 33

What happens when enzymes perform functions if they were released in an active form?

Answer 33

It could degrade cell components

Question 34

Allosteric regulation

Answer 34

Uses allosteric enzyme and modulator

Question 35

Allosteric enzyme

Answer 35

An enzyme whose activity is changed by the binding of modulators

Question 36

What is a modulator

Answer 36

A substance that binds to an enzyme at a location other than the active site and alters it’s catalytic activity.

Question 37

Example of Allosteric regulation

Answer 37

Final product becomes a noncompetitive inhibitor of an early enzyme in the pathway for biosynthesis of isoleucine.

Question 38

Genetic control

Answer 38

The synthesis of proteins is under genetic control

Question 39

Example of genetic control

Answer 39

Enzyme induction : synthesis of enzymes in response to a temporary need of the cell

Question 40

When cells are damaged or die, what do enzymes do?

Answer 40

Reside inside the cells and are released

Question 41

How to detect a condition in the concentration of enzymes in blood?

Answer 41

If level goes up. Usually, the level remains low

Question 42

Isoenzymes

Answer 42

Slightly different form of the same enzyme produced by different tissues (ex: LDH)

Question 43

What is used in the diagnosis of a wide range of diseases!

Answer 43

Serum levels of LDH due to the difference in tissue distribution of LDH isoenzymes.

Question 44

Alkaline phosphate (ALP)

Answer 44

Liver or bone disease

Question 45

Amylase

Answer 45

Pancreas disease

Question 46

Creatinine phosphokinase

Answer 46

Heart attack

Question 47

Aspartate transaminase (AST)

Answer 47

Liver and/or heart attack

Question 48

Alanine transaminase (ALT)

Answer 48

Hepatitis

Question 49

Lactate dehydrogenase (LDH) l

Answer 49

Liver and/or heart attack

Question 50

Lipase

Answer 50

Acute pancreatitis

Question 51

Lysozyme

Answer 51

Monocytic leukemia