Brainscape's Knowledge GenomeTM

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


See full index

MC Biochem 2 > Test 1 adklfjasd;lfj > Flashcards

Test 1 adklfjasd;lfj Flashcards

1
Q

Process by which noncarbohydrate precursor molecules are converted into glucose?

A

Gluconeogenesis

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

Another name for glycolysis

A

Embden Meyerhof pathway

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

These organisms cannot survive in the presence of oxygen

A

Obligate anaerobes

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

This substance must be regenerated for glycolysis to proceed

A

NAD+

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

This intermediate is necessary for the conversion of galactose to glucose

A

UDP glucose

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

This molecule is an allosteric inhibitor of phosphofructokinase

A

ATP

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

Transporter that is responsible for fructose uptake in the intestine

A

GLUT5

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

this essential nutrient is required for the carboxylation of pyruvate in humans

A

biotin

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

An allosteric activator of glycolysis

A

AMP

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

Glycolysis produced a net of ___ moles of Amp per one mole of glucose

A

2 ATP

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

Pancreatic ____ is the digestive enzyme primary responsible for the hydrolysis of dietary plant starch

A

a-amylase

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

the key enzyme that regulates the pace of glycolysis is

A

phosphofructokinase

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

The catalytic mechanism of the isomerization of a ketoses into an aldose proceed through an ___ intermediate

A

enediol

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

the common structural domain of NAD+ binding dehydrogenase is often called a ___

A

Rossman fold

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

In alcoholic fermentation, the decarboxylation of pyruvate requires a coenzyme that contains the vitamin___

A

Thiamine or B1

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

A potent allosteric activator of liver phosphofructokinase is ____
-what is it produced from

A

Fructose-2,6-bisphosohate which is produced from fructose 6-Phosphate by PFK2

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

What is the cori cycle

A

the metabolic reactions by which glucose is converted into lactate in skeletal muscle, and then lactate converted back into glucose in the liver

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

What is the first step of gluconeogenesis?

A

carboxylation of pyruvate to form oxaloacetate

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

What is the purpose of phosphorylating glucose in the cytosol?

  • trap the glucose in the cell
  • to destabilize glucose and facilitate the next series of metabolic steps
  • to convert it to more soluble form
A

Trap the glucose in the cell, because there aren’t any transporters for phosphorylated glucose
-actgivates/destabilizes glucose and facilitates the next series

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

Which of the following are reasons that glucose is a common metabolic fuel by living organisms?

  • it has a stable ring structure and is unlikely to glycosylate proteins
  • it has been found as one of the monosaccharides formed under prebiotic conditions
  • it is the only sugar used by the brain
A
  • it has a stable ring structure and is unlike to glycosylate proteins
  • it has been found as one of the monosaccharides formed under prebiotic conditions
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

What 2 3-carbon molecules are generated by the cleavage of fructose 1,6-bisphosphate?

A

Glyceraldehyde 3-phosphate

Dihydroxyacetone phosphate

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

what is a common mechanistic feature of kinases?

A

Binding of substrate induces cleft closing

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

What reaction is catalyzed by aldolase?

A

reversible cleavage of F-1,6-BP to DHAP and GAP

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

What is the function of glyceraldehyde 3-Phosphate dehydrogenase?

A

Oxidation by NAD+ and formation of acyl-phosphate

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

What is the function of a thioester intermediate such as the one formed from GAP?

A

The thioester allows the two step reaction to be coupled so the second reaction, the energetically unfavorable phosphorylation can proceed

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

What is substrate level phosphorylation

A

ATP synthesis when the phosphate donor is a substrate with high phosphorylase transfer potential

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

What is the additional metabolite that is required for the conversion of 3-phosphoglycerate to 2-phosphoglycerate

A

2,3-Bisphosphoglycerate

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

What are the primary metabolic fates of pyruvate?

A

Acetyl CoA (aerobic-matrix of mitochondria via pyruvate oxidation)

Anaerobic-Fermentation-cytoplasm
Lactate (higher eukaryotes)
Ethanol (microorganisms)

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

Fructose can enter glycolysis at 2 distinct points, depending on the tissue. How is fructose metabolized in adipose tissue?

A

Fructose is converted to fructose 6-Phosphate

  • via hexokinase
  • ATP-> ADP
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
30
Q

Lactose intolerance is caused by the deficiency of?

A

Lactase

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

How are the glycolytic enzymes regulated?

  • Transcriptional control
  • reversible phosphorylation
  • allosteric control
A

ALL of them

  • transcriptional control
  • reversible phosphorylation
  • allosteric control
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
32
Q

The primary raw material for gluconeogensis are?

A

Lactate and alanine

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

How many high-energy phosphate bonds are expended in gluconeogenesis?

A

6

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

Both hexokinase and glucokinase phosphorylate glucose. The function of glucokinase is to phosphorylate glucose in liver cells as a means to regulate blood glucose levels. Would you expect its Km to be higher or lower than hexokinase?

A

Glucokinase must be responsive to elevated blood glucose concentrations

  • Higher Km=lower affinity for glucose
  • lower binding affinity allows this enzyme to become more active at high glucose concentrations, which saturate hexokinase
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
35
Q

What two isomerization reactions occur in glycolysis? why are these steps necessary?

A

Glucose 6-Phosphate-> Fructose 6-Phosphate
-converting an aldose to a ketose allows phosphorylation at the number 1 carbon

Dihydroxyacetone PHosphate-> Glyceraldehyde 3-Phosphate
-utilize both molecules from the cleave from fructose 1,6-Bisphosphate

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

At equilibrium, there is far more DHAP than GAP. Yet the conversion of DHAP by triose phosphate isomerase proceeds readily.. Why?

A

The GAP formed is immediately removed by subsequent reactions, resulting in conversion of DHAP into GAP by the enzyme

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

How is the conversion of phosphoenolpyruvate to pyruvate accompanied by ATP formation?

A

the enol phosphate posses very high potential for phosphoryl transfer, which is due to the driving force of the tautomerizatoin of the enology to the more stable ketone

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

Give the reactions by which glycerol (from fats) can be metabolized into pyruvate or synthesized into glucose

A

1) glycerol-> glycerol 3-phosphate
- glycerol kinase
- ATP-ADP
2) Glycerol 3-Phosphate-> DHAP
- glycerol phosphate dehydrogenase
- NAD+ to NADH

After Glycerol is converted into DHAP, it is isomerize into GAP which can then either proceed down glycolysis or gluconeogenesis

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

How is glycolysis maintained under anaerobic conditions?

A

Pyruvate can be reduced to either lactate or ethanol, and this reaction is accompanied by the oxidation of NADH to regenerate NAD+

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
40
Q

How does citrate influence glycolysis

A

Phosphofructokinase is inhibited by citrate, which is an intermediate in the citric acid cycle

  • If citrate levels are high, enzyme is inhibited and fewer glucose molecules are metabolized
  • high levels in the cytoplasm indicate that biosynthetic precursors are abundant so no need to degrade additional glucose

Citrate serves as a cell indicator

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
41
Q

Why is it more sensible for phosphofructokinase to be an important control step rather than hexokinase?

A

PFK catalyzes the first commited step in glycolysis pathway.

While Hexokinase
-the production of G6P is the first step in may different pathways

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
42
Q

What two functions are attributed to substrate cycles?

A

The substrate cycles regulate glycolytic path flux by amplifying metabolic signals and they generate body heat produced by the hydrolysis of ATP

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
43
Q

Where does the citric acid cycle take place?

A

matrix of the mitochondria

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
44
Q

These proteins are tightly associated with FAD or FMN?

A

Flavoproteins

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
45
Q

What is the intermediate between citrate and isocitrate

A

cis-aconitate

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
46
Q

What is the location of succinate dehydrogenase

A

inner membarne of mitochondria

47
Q

This TCA intermediate is both at the beginning and at the end of the citric acid cycle?

A

Oxaloacetate

48
Q

This is one of the products of the citric acid cycle?

A

CO2

49
Q

This is a name suggested for associated multi enzyme complexes in metabolism

A

metabolon

50
Q

This substance is toxic because it reacts with neighboring sulhydryl groups of dihydrolipoyl groups and it blocks deoxidation to lipoamide

A

arsenite

51
Q

This type of enzyme regulation process inhibits the pyruvate dehydrogenase complex

A

phosphorylation

52
Q

This is the name applied to metabolic reactions that replenish citric acid cycle intermediates that are depleted because they were used for biosynthesis

A

anaplerotic

53
Q

Carbons from carbohydrate enter the citric acid cycle in the form of

A

Acetyl CoA

54
Q

In the citric acid cycle the ___ is produce by substrate level phosphorylation

A

GTP

55
Q

E1 of the pyruvate dehydrogenase complex requires the coenzyme ___ for proper activity

A

TPP

Thiamine Pyrophosphate

56
Q

E2 of the pyruvate dehydrogenase complex contains a lipoyl group that is covalently attached to a ___ residue of the enzyme

A

Lysine

57
Q

___ is a citric acid cycle enzyme that is also an example of an iron-sulfur protein

A

Aconitase or Succinate dehydrogenase

58
Q

The ___ cycle is a process by which plants and some bacteria can convert two-carbon acetyl units into four carbon units(succinate) for glucose synthesis, energy production, and biosynthesis

A

Glyoxylate

59
Q

During the oxidation of isocitrate, the intermediate that is decarboxylated to form alpha-ketoglutarate is

A

oxalosuccinate

60
Q

In general the citric acid cycle is inhibited under __ energy charges?

A

High

61
Q

___ is the first citric acid cycle intermediate to be oxidized

A

isocitrate

62
Q

Beriberi is caused by the deficiency of___

A

Thiamine

TPP

63
Q

What molecule initiates the citric acid cycle by reacting with oxaloacetate?

A

acetyl CoA

64
Q

What enzyme is(are) responsible for the reaction:

Pyruvate + CoA + NAD+ -> Acetyl CoA +NADH+ H+ + CO1

A

Pyruvate dehydrogenase complex

65
Q

what are the steps involved (in order) in the conversion of pyruvate to acetyl CoA

A

decarboxylation, oxidation, transfer to CoA

66
Q

What vitamins are precursors to coenzymes that are necessary for formation of Acetyl CoA from pyruvate?

A 
Thiamine
Riboflavin
Niacin
Lipoid acid
Pantothenic acid
67
Q

What functions as a “flexible swing arm” when it transfers the reaction intermediate from one active site to the next?

A

Lipoamide

68
Q

Formation of citrate from acetyl CoA and Oxaloacetate is a __ reaction

A

condensation

69
Q

What is/are the chemical changes involved in the conversion of citrate into isocitrate?

A

dehydration followed by hydration

70
Q

In which reaction is GTP (or ATP) directly formed in the citric acid cycle?

A

conversion of Succinyl CoA to Succinate

71
Q

In which step of the citric acid cycle is FADH2 formed?

A

Succinate to fumurate

72
Q

What conditions will activate pyruvate dehydrogenase kinase which catalyzes the phosphorylation and inactivation of E1 in the pyruvate dehydrogenase complex?

A

elevated concentrations of NADH and ATP

73
Q

Approximately how many ATP or GTP equivalents are produced during one turn of the citric acid cycle?

A

10

74
Q

In addition to pyruvate dehydrogenase, what other enzymes are key regulatory sites in the citric acid cycle?

A

isocitrate dehydrogenase
a-ketogluterate dehydrogenase
citrate synthase (in bacteria)

75
Q

They glyoxylate cycle enables plants to survive using only?

A

acetate

76
Q

List the 5 coenzymes that are required for the oxidative decarboxylation of pyruvate and a-ketoglutarate and give the essential nutrient (vitamin) that is required for each

A 
Thiamine pyrophosphate (TPP)-thiamine, B1
Lipoamide- lipoic acid
NAD+, niacin
FAD- riboflavin, B2
Coenzyme A-pantothenic acid
77
Q

Explain why GTP is energetically equivalent to an ATP in metabolism

A

nucleoside diphosphokinase reversibly transfers a P group from GTP to ATP

78
Q

Why is the observed electron transfer from FADH2 to NAD+ unusual?

A

it is unusual because the electrons are passed to the NAD+ from FADH2
-transfer usually in other direction

79
Q

How is succinate dehydrogenase unique when compared to other enzymes in the citric acid cycle?

A

only enzyme embedded in the mitochondrial inner membarne

-directly associated with electron transport chain

80
Q

where does oxidative phosphorylation occur in eukaryotes?

A

Mitochondria

81
Q

An ATP-generating process in which an inorganic substance such as oxygen serves as the ultimate electron acceptor?

A

Respiration

82
Q

The permeability of the outer mitochondrial membrane is primarily due to the presence of these substances

A

Porins

83
Q

This electron carrier is a derivative of quinone and has an isoprenoid tail

A

coenzyme Q

84
Q

This enzyme catalyzes the reduction of O2

A

cytochrome c oxidase (C)

85
Q

This prosthetic group is present in complex I, II, III of electron transport

A

iron-sulfur clusters

86
Q

This citric acid enzyme is also apart of an electron-transport complex?

A

succinate dehydrogenase

87
Q

This is the name given to the hypothesis proposed by Peter Mitchell Explain how ATP synthesis is coupled to electron transport

A

Chemiosmotic theory

88
Q

Atractyloside inhibits this mitochondrial protein

A

ATP-ADP translocase

89
Q

This is a process by which cytoplasmic NADH can be re-oxidized by O2 using the electron-transport system

A

malate aspartate shuttle

90
Q

A strong oxidizing agent has a strong tendency to ___ electrons

A

acept

91
Q

In the initial step of Complex I, two high-potential electrons are transferred from NADH to the __ prosthetic group of the complex

A

FMN

92
Q

cytochrome ___ is the only water-soluble cytochrome of the electron transport chain

A

c

93
Q

Complex III contains two Heme A groups and 3___ions

A

copeer

94
Q

___ carries electrons from complex III to complex IV

A

cytochrome C

95
Q

The transfer of a single electron to O2 forms the reactive __ ion

A

superoxide

96
Q

__ is a molecular assembly in the inner mitochondrial membrane that carries out synthesis of ATP

A

ATP synthase

97
Q

In the glycerol phosphate shuttle, cytoplasmic glycerol phosphate dehydrogenase uses cytoplasmic NADH to reduce ___ to glycerol 3-Phosphate

A

DHAP

98
Q

Acceptor control of oxidative phosphorylation means that the rate of respiration depends upon the level of ___

A

ADP

99
Q

___ is a poison because it blocks the flow of electrons from cytochrome c to oxygen

A 
CO
or Cyanide (CN-)
or Azide (N3-)
100
Q

What type of gradient is critical to ATP formation by oxidative phosphorylation

A

Proton Gradient

101
Q

When glucose is totally oxidized to CO2 and H2O, how many ATP molecules are made by oxidative phosphorylation relative to the maximum yield?

A

26 out of 30

102
Q

What is the chemical effect of oligomycin on aerobic metabolism?

A

Blocks the proton transfer through F0 of ATPsynthase and therefore blocks the phosphorylation of ADP to form ATP

103
Q

What is the correct path taken by a pair of electrons as it travels down the electron transport chain?

A

FADH2-> Complex II-> CoQ->Complex III->Cytoplasms C->complex IV-> O2
NADH->Complex I

104
Q

In prokaryotes the site of ATP-synthesizing machinery is

A

cytoplasmic membrane

105
Q

electron flow down the electron transport chain leads to

A

transport of protons across the inner mitochondrial membrane from inside the matrix to the inter membrane space

106
Q

Coenzyme Q is also called?

A

Ubiquinone

107
Q

What complex in ETC doesn’t pump protons?

A

Complex II

108
Q

In proteins these amino acid residues usually complex to the iron sulfur clusters

A

Cys

109
Q

What is a cytochrome

A

protein that transfers electrons, and also contains a heme prosthetic group

110
Q

In the rieske center, the iron sulfur center is coordinate to the Amino acid(s)?

A

His

111
Q

What is the net ATP obtained rom one cytoplasmic NADH when it is reoxidizes by the electron transport chain using the glycerol 3-phosphate shuttle?

A

2

112
Q

In the malate aspartate shuttle, electrons from NADH are transferred to ___, forming malate

A

oxaloacetate

113
Q

Explain why less ATP is made from the reoxidation of FADH2 as compared to NADH

A

complex II doesn’t pump protons thus fewer ATP molecules are ultimately made (Complex I does pump protons)

114
Q

How is oxidative phosphorylation regulated?

A

Acceptor Control

  • electrons do not flow unless ADP is available to be simlutaneously phosphorylated to ATP
  • therefore synthesis of ATP does not occur unless ADP levels are high

MC Biochem 2 (31 decks)

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