Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

BCMB 401 > Chapter 15 > Flashcards

Chapter 15 Flashcards

1
Q

Glucose is metabolized to pyruvate in 10 linked reactions. Under anaerobic conditions, pyruvate is metabolized to what? Under aerobic conditions?

A

Anaerobic: lactate
Aerobic: acetyl CoA (which ate oxidized to CO2)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

Living organisms require a continual input of free energy for what three major purposes?

A

1) the performance of mechanical work in muscle contractions and cellular movements 2) the active transport of molecules and ions 3) the synthesis of macromolecules and other biomolecules from simple precursors

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

Metabolism?

A

Essentially a linked series of chemical reactions that begins with a particular molecule and converts it into some other molecule or molecules in a carefully defined fashion

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

Which enzymes are predominant in metabolism?

A

Allosteric

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

Metabolic pathways can be divided into what two broad classes?

A

1) those that convert energy from fuels into biologically useful forms 2) those that require inputs of energy to proceed

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

Catabolic reactions (catabolism)?

A

Those reactions that transform fuels into cellular energy

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

Anabolic reactions (anabolism)?

A

Those reactions that require energy such as synthesis of glucose, fats, or DNA

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

Why are the useful forms of energy produced in catabolism employed in anabolism?

A

To generate complex structures from simple ones or energy-rich states from energy-poor ones

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

Amphibolic pathways?

A

Pathways that are either anabolic or catabolic

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

Formula for catabolism?

A

Fuel (carbohydrates, fats) -> CO2 + H2O + useful energy

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

Formula for anabolism?

A

Useful energy + simple precursors –> complex molecules

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

What two criteria must a pathway satisfy?

A

1) the individual reactions must be specific 2) the entire set of reactions that constitute the pathway must be thermodynamically favored

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

What does the free energy of a reaction depend on?

A

The nature of the reactants and products and in their concentrations

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

What is the overall free energy change for a chemically coupled series of reactions equal to?

A

The sum of the free energy changes of the individual steps

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

How can a thermodynamically unfavorable reaction be made favorable?

A

When it is coupled to a thermodynamically favorable reaction.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

How are metabolic pathways formed?

A

By the coupling of enzyme-catalyzed reactions such that the overall free energy of the pathway is negative

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

How is metabolism facilitated?

A

ATP

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

Function of ATP?

A

The free-energy donor in most energy-requiring processes such as motion, active transport, or biosynthesis.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

How is ATP made?

A

By catabolic reactions that extract energy from fuels such as carbohydrates and fats which are converted to ATP

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

Components of ATP?

A

Adenosine, ribose, triphopshate

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

The active form of ATP is usually a complex of ATP with ___.

A

Mg 2+ or Mn 2+

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
22
Q

Why is ATP an energy-rich molecule?

A

Because its triphosphate unit contains two phosphoanhydride bonds.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
23
Q

Role of ATP?

A

Energy carrier

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
24
Q

A large amount of free energy is liberated when ATP is hydrolyzed to what two forms?

A

1) ADP and orthophosphate (Pi) 2) AMP and pyrophosphate (PPi)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
25
Q

What is the universal energy currency in biological systems?

A

ATP

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
26
Q

ATP hydrolysis is exergonic or endergonic?

A

Exergonic

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
27
Q

What is the fundamental mode of energy exchange in biological systems?

A

The ATP-ADP cycle

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
28
Q

What three triphosphates are analogous to ATP?

A

GTP, UTP, CTP

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
29
Q

___ catalyze the transfer of the terminal phosphoryl group from one
nucleotide to another.

A

Enzymes

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
30
Q

What is the phosphorylation of nucleoside mono phosphates catalyzed by?

A

Nucleoside monophosphate kinases

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
31
Q

What is the phosphorylation of nucleoside diphosphates catalyzed by?

A

Nucleoside diphosphate kinase

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
32
Q

What two electron carriers are derivatives of ATP?

A

NAD+ and FAD

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
33
Q

How does ATP hydrolysis drive metabolism?

A

By shifting the equilibrium of coupled reactions

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
34
Q

What are the three purposes of phosphoryl transfer?

A

1) used to derive otherwise endergonic reactions 2) alter the energy conformation of a protein 3) serve as a signal to alter the activity of a protein

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
35
Q

What is the phosphoryl group donor in phosphoryl transfer?

A

ATP

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
36
Q

Why is ATP an activated carrier of phosphoryl groups?

A

Because phosphoryl group transfer from ATP is an exergonic process

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
37
Q

What are the three ways activated carriers function as coenzymes?

A

1) activated carriers of electrons for fuel oxidation 2) an activated carrier of electrons for reductive biosynthesis 3) an activated carrier of two-carbon fragments

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
38
Q

In aerobic organisms, what is the ultimate electron acceptor in the oxidation of fuel molecules?

A

O2

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
39
Q

What is the major electron carrier in the oxidation of fuel molecules?

A

Nicotinamide adenine dinucleotide (NAD+)

40
Q

What is the active part of NAD+?

A

Its Nicotinamide ring, a pyridine derivative synthesized from the vitamin niacin

41
Q

Which is the oxidized/reduced form: NAD+ or NADH?

A

Oxidized: NAD+
Reduced: NADH

42
Q

What is the reactive part of FAD?

A

The isoalloxazine ring, a derivative of the vitamin riboflavin

43
Q

Difference/similarities between NAD+ and FAD?

A

Similar: they can accept two electrons
Differences: FAD can take up 2 protons unlike NAD+

44
Q

Why is reducing power needed in addition to ATP?

A

High potential electrons are required in most biosynthesis because the precursors are more oxidized than the products.

45
Q

What is the electron donor in most reductive biosyntheses?

A

NADPH

46
Q

What is the difference between NADPH and NADH?

A

NADPH is used almost exclusively for reductive biosyntheses. NADH is used primarily for the generation of ATP.

47
Q

What tag on NADPH enables enzymes to distinguish between high-potential electrons to be used in anabolism and those to be used in catabolism?

A

The extra phosphoryl group

48
Q

What is the reactive site of CoA?

A

The terminal sulfhydryl group

49
Q

What bonds are acyl groups linked to CoA by?

A

Thioester bonds

50
Q

Why does acetyl CoA have a high acetyl-group transfer potential?

A

Because transfer of the acetyl group is exergonic and acetyl CoA carries an activated acetyl group just as ATP carries an activated phosphoryl group

51
Q

Why is the kinetic stability of these molecules in the absence of specific catalysts essential for their biological function?

A

Because it enables enzymes to control the flow of free energy and reducing power

52
Q

What are almost all the activated carriers that act as coenzymes derived from?

A

vitamins

53
Q

Vitamins?

A

organic molecules that are needed in small amounts in the diets of some higher animals

54
Q

What is the coenzyme of vitamin B1 (thiamine)?

A

thiamine pyrophosphate

55
Q

What is the typical reaction type of Vitamin B1?

A

aldehyde transfer

56
Q

What is the coenzyme of B2 (riboflavin)?

A

flavin adenine dinucleotide (FAD)

57
Q

What is the typical reaction type of B2?

A

oxidation-reduction

58
Q

What is the coenzyme of B6 (pyridoxine)?

A

pyridoxal phosphate

59
Q

What is the typical reaction type of B6?

A

group transfer to or from amino acids

60
Q

What is the coenzyme of niacin?

A

NAD+

61
Q

What is the typical reaction type of niacin?

A

oxidation-reduction

62
Q

What is the coenzyme of pantothenic acid?

A

coenzyme A

63
Q

What is the typical reaction type of pantothentic acid?

A

carboxylation and carboxyl-group transfer

64
Q

What is the coenzyme of biotin?

A

biotin-lysine adducts (biocytin)

65
Q

What it the typical reaction type of biotin?

A

ATP-dependent carboxylation and carboxyl-group transfer

66
Q

What is the coenzyme of folic acid?

A

tetrahydrofolate

67
Q

What is the typical reaction type of folic acid?

A

transfer of one-carbon components; thymine synthesis

68
Q

What is the coenzyme of B12?

A

5’-deoxyadenosyl cobalamin

69
Q

What is the typical reaction type of B12?

A

transfer of methyl groups; intramolecular rearrangements

70
Q

What are the noncoenzyme vitamins?

A

A,C,D,E,K

71
Q

What are the 6 reaction types of metabolism?

A

1) oxidation-reduction 2) ligation 3) isomerization 4) group-transfer 5) hydrolytic 6) functional groups may be added to double bonds to form single bonds or removed from single bonds to form double bonds

72
Q

What two oxidation-reduction reactions are components of the citric acid cycle?

A

Succinate + FAD –> Fumarate + FADH2; Malate + NAD+ –> Oxaloacetate + NADH + H+

73
Q

Ligation bonds?

A

form by using free energy from ATP cleavage

74
Q

What is oxaloacetate formed from?

A

pyruvate and CO2 by ligation reactions (pyruvate + CO2 + ATP + H2O –> oxaloacetate + ADP + Pi + H+)

75
Q

Isomerization reactions?

A

rearrange atoms within a molecule

76
Q

Example RxN of isomerization?

A

citrate –> isocitrate

77
Q

Group transfer reactions?

A

used to synthesize ATP by transferring a phosphoryl group from the activated phosphoryl-group carrier, ATP, to glucose (Glucose + ATP –> Glucose-6-Phosphate + ADP)

78
Q

Hydrolyic reactions?

A

cleave bonds by the addition of water; a means to break down large molecules in order to facilitate further metabolism or reuse some of the components for biosynthetic purposes

79
Q

Functional group reactions?

A

dehydration reactions (Fructose-1,6-Bisphospate –> DHAP + GAP

80
Q

How is metabolism regulated?

A

1) amounts of enzymes 2) catalytic activities 3) accessibility of substrates

81
Q

How do you control the amount of enzymes?

A

adjusted by the change in the rate of transcription of the genes encoding them

82
Q

How do you control the catalytic activity?

A

reversible allosteric control (feedback ihibition); reversible covalent modification; hormones; energy charge

83
Q

What is reversible allosteric control?

A

instantaneous (inhibition of aspartate transcarbamoylase by citidine triphosphate)

84
Q

Feedback inhibition?

A

two pathways with a common initial step may each be inhibited by its own product and activated by the product of the other pathway

85
Q

Reversible covalent modification?

A

glycogen phosphorylase, the enzyme catalyzing the breakdown of glycogen, a storage form of sugar, is activated by the phosphorylation of a particular serine residue when glucose is scarce

86
Q

How do hormones coordinate metabolic relations?

A

by regulating the reversible modification of key enzymes (ex. epinephrine triggers a signal-transduction cascade in muscle resulting in the phosphorylation and activation of key enzymes and leading to the rapid degradation of glycogen to glucose, which is then used to supply ATP for muscle-contractions

87
Q

What are ATP-generating (catabolic) pathways inhibited by?

A

a high energy charge

88
Q

What are ATP-utilizing (anabolic) pathways stimulated by?

A

a high energy charge

89
Q

Energy charge = ?

A

([ATP] + 1/2[ADP]) / ([ATP] +[ADP]+ [AMP])

90
Q

Phosphorylation Potential?

A

[ATP]/ ([ADP] + [Pi])

91
Q

How do you control the accessibility of substrates?

A

compartmentalization (segregates opposed reactions)

92
Q

Oxidation-reduction?

A

electron transfer

93
Q

Ligation requiring ATP cleavage?

A

formation of covalent bonds

94
Q

Isomerization?

A

rearrangement of atoms to form isomers

95
Q

Group transfer?

A

transfer of a functional group from one molecule to another

96
Q

Hydrolytic?

A

cleavage of bonds by the addition of water

97
Q

Addition or removal of functional groups?

A

addition of functional groups do double bonds or their removal to form double bonds

BCMB 401 (13 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2024 Bold Learning Solutions. Terms and Conditions