Second Half F24II: Lecture Slides 32 - 57

Question 1

What is Catabolism?

Answer 1

The breakdown of large molecules into simpler products

(Proteins, Lipids, Carbohydrates to CO2, H20, NH3)

Question 2

What is Anabolism?

Answer 2

The building of larger molecules from simple precursors

(Sugars. Amino Acids, Fatty acids to Proteins, Lipids, Nucleic Acids)

Question 3

What do catabolic pathways do?

Answer 3

They typically converge

Question 4

What happens to the carbon “skeletons” of most sugars, fats and amino acids?

Answer 4

They are converted into a metabolite called Acetyl Coenzyme A (Acetyl CoA)

Question 5

What can Acetyl CoA be used to build?

Answer 5

Everything from fatty acids to steroids to components of proteins and nucleic acids

Question 6

What is a metabolic pathway?

Answer 6

A series of enzyme-catalyzed reactions

Question 7

What does a metabolic pathways convert?

Answer 7

A precursor (A) into a product (E) through a series of intermediates known as metabolites

Question 8

What does each step in a metabolic pathway bring?

Answer 8

A small but specific chemical change.

Question 9

What does irreversible mean?

Answer 9

It contains on reaction that is thermodynamically very favourable

Question 10

How are metabolic pathways regulated?

Answer 10

• Transcriptional control of enzyme levels
• Inhibition or activation of enzyme activity

Question 11

What are the 3 ways of Elucidation of Metabolic Pathways?

Answer 11

1.) Metabolic Inhibitors

2.) Biochemical Genetics

3.) The use of Radioactive Labeled Substrates

Question 12

What does the Use of Metabolic Inhibitors do?

Answer 12

When you inhibit an enzyme, you can isolate it and study it.

Question 13

What can you study using Biochemical Genetics?

Answer 13

a. Genetic Diseases

b. The use of Auxotrophic Mutants

Question 14

What can you do by studying auxotrophic mutants?

Answer 14

Identify the mutants by their requirement for the end product of the pathway and identify the metabolites that accumulate

Question 15

What happens if a compound is synthesized with a 14C atom in it?

Answer 15

The compound, and any products derived from the 14C atom will be radioactive and is easily traceable.

Question 16

How can a 14C be traced?

Answer 16

It releases a little flash of energy when it decays

Question 17

What is an oxidation reaction?

Answer 17

The loss of electrons

Question 18

What is a reduction reaction?

Answer 18

The gain of electrons

Question 19

How do you figure out if B or A has a greater tendency to accept available e-?

Answer 19

Based on their Standard Reduction Potential (E0’) of the two half reactions

Question 20

What is E0’?

Answer 20

The Standard Reduction Potential at pH 7 and 25 degrees celsius

Question 21

What is SHE?

Answer 21

H2 -> 2H+ + 2e-

Question 22

What is the E0’ of SHE?

Answer 22

-0.42 V

Question 23

What can E0’ be used for?

Answer 23

To predict the direction of electron flow

Question 24

What is the strength of the tendency proportional to?

Answer 24

Delta E0’

Question 25

When can redox reaction proceed spontaneously?

Answer 25

IF Delta E0' is greater than 0 (a positive number)

Question 26

When will Gibbs free energy be spontaneous?

Answer 26

When it is negative

Question 27

In redox reactions, what is the higher value?

Answer 27

Electron Acceptor (oxidizing agent)

Question 28

What is the lower value?

Answer 28

Electron Donor (reducing agent)

Question 29

What is △E0' equal to (equation)

Answer 29

E0'(acceptor) - E0'(donor)

Question 30

How do electrons always flow?

Answer 30

From a redox pair with lower E0' to higher E0'

Question 31

What is the equation for Gibbs Free Energy?

Answer 31

-nFE0'

Question 32

What is Faradays Constant?

Answer 32

96.5 x 103 J/V mol

Question 33

What can some enzymes use to carry out their functions?

Answer 33

1.) Inorganic Ions 2.) Coenzymes

Question 34

What are inorganic Ions?

Answer 34

Mg2+, Zn2+, Fe2+, Mn2+, Cu2+

Question 35

What are coenzymes?

Answer 35

Complex organic or metallooorganic compounds that act as transient carriers of specific functional groups.

Question 36

What are many coenzymes derivates of?

Answer 36

Adenosine

Question 37

What is ATP a carrier/donor of?

Answer 37

Many phosphate groups

Question 38

What is ATP used for?

Answer 38

To phosphorylate many types of molecules such as sugars, lipids, proteins

Question 39

What does phosphorylation do?

Answer 39

The addition of a phosphoryl (PO3) group to a molecule.

Question 40

What is Phosphorylation important for?

Answer 40

In biological systems, this reaction is vital for the cellular storage and transfer of free energy using energy carrier molecules.

Question 41

What is kinase?

Answer 41

A family of enzymes that phosphorylate molecules with the help of ATP

Question 42

What is CoA a carrier of?

Answer 42

Acid groups

Question 43

What is CoA derived from?

Answer 43

Pantothenic Acid

Question 44

What are the groups found in CoA

Answer 44

B-mercaptoethylamine, pantothenic acid, adenosine

Question 45

What happens when CoA is mixed with organic acids?

Answer 45

Forms thioester derivatives

Question 46

What is a thioester?

Answer 46

Sulfur analogue of an ester (O has been replaced by an S)

Question 47

What is a coenzyme A thioester derivative called?

Answer 47

An acyl CoA

Question 48

In the case of acetic acid, what is the corresponding Acetyl CoA derivative called?

Answer 48

Acetyl CoA

Question 49

What are NAD+, NADP+, FAD and FMN involved in?

Answer 49

The electrons that are removed from the substrates are transferred on to these cofactors reducing them and conserving the energy of oxidation

Question 50

What are the cofactors NAD+ and FAD involved in?

Answer 50

Beta Oxidation

Question 51

What type of nucleotide are NAD and NADP?

Answer 51

Pyrimidine Nucleotides (single ring)

Question 52

What are NAD and NADP derived from?

Answer 52

The vitamin niacin (B3)

Question 53

What does the structure of NAD and NADP consist of?

Answer 53

Niacin (nicotinamide ring) and Adenosine

Question 54

Where do redox reactions occur - NAD and NADP?

Answer 54

At the nicotinamide ring

Question 55

What happens during oxidation of substrates?

Answer 55

Two hydrogen atoms are removed from the substrate

Question 56

What does the oxidized form of NAD and NADP accept?

Answer 56

A hydride (H-) ion - equivalent of a proton and two electrons

Question 57

What does the hydride ion make NAD and NADP?

Answer 57

Reduced to become NADH and NADPH

Question 58

Where is the other proton released?

Answer 58

Into the environment

Question 59

What is NAD+ used as?

Answer 59

The oxidizing agent in fatty acid oxidation, TCA cycle - The resulting NADH is reoxidizes via ETC to generate energy

Question 60

What is NADPH used as?

Answer 60

The reducing agent (losing electrons) in biosynthesis

Question 61

What are FAD and FAM?

Answer 61

The flavin nucleotides

Question 62

What vitamin. are FAD and FAM derivates of

Answer 62

Riboflavin (B2) vitamin

Question 63

What do Flavin Nucleotides act as?

Answer 63

Prosthetic groups (tightly bound to the enzyme helping out)

Question 64

What is the structure of FAD?

Answer 64

Adenosine and Vitamin B2 (riboflavin)

Question 65

What is the structure of FMN?

Answer 65

Monophosphate group and a riboflavin B2 vitamin

Question 66

What can flavin nucleotides accept?

Answer 66

One or two electrons (in the form of one or two hydrogen atoms) from substrates undergoing oxidation

Question 67

What are the fully reduced forms of the nucleotides FAD and FMP?

Answer 67

FADH2 and FMNH2

Question 68

What happens when only one electron is accepted?

Answer 68

They form the stable semiquinone radical DADH and FMNH

Question 69

Due to the ability for FMN and FAD to participate in either one or two electron transfers, what are they involved in?

Answer 69

A greater diversity of reactions than the NAD(P) linked dehydrogenases