Micro1009- Chapter 5 Microbial Metabolism And Enzymes

Front 1

Metabolism

Back 1

All the chemical reactions within a living organism

Front 2

Catabolism/Catabolic Reactions

Back 2

- generally hydrolytic

- breakdown of complex organic molecules into simpler compounds

- exergonic

Front 3

Hydrolytic

Back 3

Reactions that use water in the breaking down of bonds

Front 4

Exergonic

Back 4

Energy is released

Front 5

Types of metabolism

Back 5

1. Catabolism

2. Anabolism

Hint 5

2

Front 6

Anabolism/anabolic reactions

Back 6

- Building of complex molecules from simpler ones

- endergonic

Front 7

Endergonic

Back 7

Energy is required

Front 8

Example of anabolism

Back 8

Dehydration synthesis: Reactions that release water

Front 9

Collision Theory

Back 9

All molecules are constantly in motion and constantly colliding with each other

If there is enough activation energy when these molecules collide, it will lead to a chemical reaction

Front 10

Chemical reaction

Back 10

The breaking of chemical bonds and/or the forming of new bonds

Front 11

Enzymes

Back 11

Organic catalysts that speed up and direct biochemical reactions without being altered themselves

Front 12

How do enzymes speed up reactions?

Back 12

By lowering the energy of activation

Front 13

How much of a difference do enzymes make?

Back 13

Enzymes speed up the reaction rate a million times compared to un-catalyzed reactions

Front 14

Substrate

Back 14

The specific molecule the enzyme interacts with

Enzymes are substrate specific!

Front 15

Most enzymes we study are ____

Back 15

Proteins

Front 16

RNA enzymes

Back 16

Ribozymes:

Old enzymes that developed early in the evolution of life

Front 17

Describe enzyme action

Back 17

1. Substrate bonds with the active site, forming an enzyme-substrate complex

2. The substrate is changed to the product(s) and is released, leaving the enzyme unchanged

Front 18

Active site

Back 18

The spot on an enzyme that can form bonds with a substrate

Front 19

Enzyme-substrate complex

Back 19

A temporary bond between an enzyme and a substrate during enzyme action

Front 20

Substrate specific

Back 20

Enzymes only react with their specific substrate(s)

Front 21

How are enzymes often named?

Back 21

After their substrate

Front 22

Examples of enzymes named after their substrate

Back 22

1. Lipase (breaks down lipids)

2. Sucrase (breaks down sucrose)

3. Urease (breaks down urea)

4. Protease (breaks down protein)

5. DNase (breaks down DNA)

Hint 22

5

Front 23

Categories of enzyme classification

Back 23

1. Oxidoreductases

2. Transferase

3. Hydrolase

4. Lyase

5. Isomerase

6. Ligases

Hint 23

6

Front 24

Oxioreductases

Back 24

Involved in oxidation and reduction reactions

Front 25

Reduction reactions

Back 25

The removing or adding of electrons

Front 26

Transferase

Back 26

Transfers functional groups, such as an amino, acetyl, or phosphate group

Front 27

Hydrolase

Back 27

Involved in hydrolysis

Front 28

Hydrolysis

Back 28

Breaking down molecules in water

Front 29

Lyase

Back 29

Removal of groups without hydrolysis

Front 30

Isomerase

Back 30

Rearrangement of atoms within a molecule

Front 31

Ligases

Back 31

Joining of two molecules, usually coupled with the breakdown of ATP)

Front 32

Components of enzymes with more than just proteins

Back 32

1. Apoenzyme

2. Cofactor/Coenzyme

Front 33

Apoenzyme

Back 33

The protein part of an enzyme

Front 34

Cofactor/Coenzyme

Back 34

Non-protein part of an enzyme. Many are derived from vitamins

Can be inorganic, like an ion, or organic

Front 35

Holoenzyme

Back 35

The components of an enzyme put together

Front 36

Examples of coenzymes derived from vitamins

Back 36

1. NAD

2. FAD

3. CoA

Hint 36

3

Front 37

Nicotinamide adenine dinucleotide

Back 37

NAD

Cornzyme derived from Niacin

Front 38

Niacin

Back 38

Vitamin involved in cellular respiration

Front 39

Flavin adenine dinucleotide

Back 39

FAD

Coenzyme derived from Riboflavin

Front 40

Riboflavin

Back 40

A vitamin involved in cellular respiration

Front 41

Coenzyme A

Back 41

CoA

Coenzyme derived from Panthothenic acid

Front 42

Panthothenic acid

Back 42

Vitamin involved in cellular respiration

Front 43

Factors that influence enzyme activity

Back 43

1. Denaturation of an active protein

2. Temperature

3. pH

4. Substrate concentration

Hint 43

4

Front 44

Denaturation

Back 44

Loss of shape

Front 45

Most enzymes are ____

Back 45

Proteins

Front 46

How does temperature affect enzyme activity?

Back 46

- chemical reaction rates increase a temperature increases

- most enzymes have an optimum temperature, beyond which will reduce the rate

- eventually, high temperatures will denature most enzymes

Front 47

How does pH affect enzyme activity?

Back 47

- Most enzymes have an optimum pH at which their activity is the highest

- pH above or below optimum pH will cause a decline in reaction rate

- extreme pH will denature enzymes

- optimum pH varies

Front 48

How does substrate concentration affect enzyme activity?

Back 48

- a higher concentration of substate will increase reaction rate until saturation

- after saturation, any further increase will not increase enzyme activity

Front 49

Saturation

Back 49

The point at which all active sites are occupied

Front 50

Inhibitors

Back 50

Decrease or stop enzyme activity

Front 51

Types of inhibitors

Back 51

1. Competitive

2. Non-competitive

3. Reversible

4. Irreversible

Hint 51

4

Front 52

Competitive inhibitors

Back 52

Competes with the substrate for the the active site

Front 53

Non-competitive inhibitors

Back 53

Bind to the allosteric site

Front 54

Allosteric site

Back 54

The "back door" site

When a non-competitive inhibitor binds to this site, the active site shrinks

Front 55

Examples of competitive inhibitors

Back 55

1. Penicillin

2. Sulfanilamide

Front 56

Penicillin as an inhibitor

Back 56

Competes for the active site of the enzyme involved in the synthesis of the pentaglycine crossbridges

Front 57

Sulfanilamide

Back 57

- used to treat bacterial infections before antibiotics (still used today)

- competes for the active site on the enzyme that converts PABA (para aminobenzoic acid) into folic acid

Front 58

Examples I'd non-competitive inhibitors

Back 58

- cyanide

- heavy metals (Hg, Ag)

Front 59

Heavy metals as inhibitors

Back 59

Disrupt the disulfide bridges and denature the enzymes

Front 60

Reversible inhibitor

Back 60

Structurally very similar to its substrate

Binds temporarily to the substrate and does not alter the structure of the enzyme

Front 61

Example of a reversible inhibitor

Back 61

Protease inhibitor:

Part of HIV therapy

Will not permanently have an effect unless one continues to take the medication

Front 62

Irreversible inhibitor

Back 62

Binds covalently to the enzyme, permanently altering its structure

Front 63

Covalent bond

Back 63

A chemical bond that involves the sharing of electron pairs between atoms

Front 64

Examples of irreversible inhibitors

Back 64

1. Penicillin

2. Cyanide

Hint 64

2

Front 65

Feedback Inhibition

Back 65

- Control mechanism that prevents the cell from making too much of any substance

- Requires a chain of enzymes working together to make a final end-product

- once it reaches a certain concentration, the final end-product acts as a noncompetitive inhibitor to one of the early enzymes in the chain

Front 66

What happens if the concentration of the final product dips during feedback inhibition?

Back 66

The end product falls off the enzyme and the process begins again