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Year Two > Pentose phosphate pathway > Flashcards

Pentose phosphate pathway Flashcards

1
Q

The three metabolic pathways of glucose are?

A

Oxidation via glycolysis to yield pyruvate, ATP & NADH
Formation of polysaccharides
Oxidation via PPP to yield ribose-5-phosphate & NADPH for reductive biosynthesis

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2
Q

An alternative metabolic pathway for glucose oxidation in which no ATP is generated is called?

A

Pentose phosphate pathway (PPP)

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3
Q

PPP is also known as?

A

Hexose monophosphate shunt (HMP Shunt)

6-Phosphogluconate pathway

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4
Q

Four properties of PPP are?

A

More complex pathway than glycolysis
More anabolic in nature
Takes place in the cytosol
Concerned with the biosynthesis of NADPH & pentoses

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5
Q

Four tissues that are highly active in HMP shunt are?

A

Adrenal gland
Liver
Testes
Lactating mammary gland

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6
Q

The two products of PPP are?

A

NADPH

Pentose

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7
Q

Four importance of NADPH are?

A

Biosynthesis of fatty acids and steroids
detoxification of drugs
Phagocytosis requires NADPH
NADPH keeps the Fe2+ iron of haemoglobin in a reduced state

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8
Q

Two importance of Pentoses are?

A

Use in the synthesis of nucleic acids and many nucleotides

Produces carbohydrates for cell wall synthesis for some growing organisms

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9
Q

Nucleic acid examples are?

A

DNA

RNA

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10
Q

Nucleotide examples are?

A

ATP
NAD+
coA

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11
Q

HMP Shunt sequence of reactions are divided into?

A

Two phases

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12
Q

The first phase of the HMP shunt is?

A

Oxidative phase(non-reversible)

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13
Q

The oxidative phase has how many ___reactions

A

3

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14
Q

In the first reaction, __1__ catalyzes the conversion of Glucose-6-phosphate into __2__

A
  1. Glucose-6-phosphate dehydrogenase(G6PD)

2. 6-phosphogluconolactone

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15
Q

The two products of the first reaction are?

A

6-phosphogluconolactone and NADPH

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16
Q

In the second reaction, 6-phosphogluconolactone is hydrolyzed into?

A

6-phospho-D-gluconate

Gluconolactonase

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17
Q

In the third reaction, oxidative decarboxylation of 6-phospho-D-gluconate is done to produce?

A

Ribulose-5-phosphate
NADPH
(6 phosphogluconate dehydrogenase)

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18
Q

PPP is most active in?

A

Cells where large amounts of lipids are synthesized (liver, adipose tissue, mammary glands)
Cells that are at high risk for oxidative damage (RBC)

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19
Q

Under the oxidative phase of PPP, Glucose-6-phosphate undergoes __1__ & _2__ to give a pentose, and D-ribulose-5-phosphate

A

Dehydrogenation

Decarboxylation

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20
Q

Non-oxidative phase has ___ reactions

A

2

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21
Q

In the first reaction, ribulose-5-phosphate is converted to ribose-5-phosphate by?

A

Ribulose-5-phosphate isomerase

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22
Q

Ribulose-5-phosphate may also be converted to xylulose-5-phosphate by?

A

Ribulose-5-phosphate epimerase (main reaction)

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23
Q

__ &__ catalyze the interconversions of trioses, Pentoses & hexoses

A

Transketolase

Transaldolase

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24
Q

A TPP requiring enzyme that transfers two carbon units from a ketose to an aldose is called?

A

Transketolase

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25
Q

Transketolase catalyzes how many reactions?

A

2

26
Q

In the first reaction, transketolase transfers 2 carbon units from xylulose-5-phosphate to?

A

Ribose-5-phosphate

27
Q

The products of the first transketolase-catalyzed reaction are?

A

Glyceraldehyde-3-phosphate

Sedoheptulose-7-phospate

28
Q

In the second reaction, 2 carbon units are transferred from another xylulose-5-phosphate to?

A

Erythrose-4-phosphate

29
Q

The products of the second transketolase-catalyzed reaction are?

A

Glyceraldehyde-3-phosphate

Fructose-6-phosphate

30
Q

The coenzyme form of thiamine is?

A

Thiamine pyrophosphate (TPP)

31
Q

An enzyme that transfers three-carbon units from a ketose to an aldose is called?

A

Transaldolase

32
Q

In the reaction catalyzed by transaldolase, 3 carbon units are transferred from sedoheptulose-7-phospate to?

A

Glyceraldehyde-3-phosphate

33
Q

The products formed from the transaldolase-catalyzed reaction are?

A

Fructose-6-phosphate

Erythrose-4-phosphate

34
Q

The result of the non-oxidative phase of the reaction pathway is the synthesis of?

A

Ribose-5-phosphate
Glyceraldehyde-3-phosphate (G3P)
Fructose-6-phosphate(F6P)

35
Q

The glycolytic intermediates are?

A

Glyceraldehyde-3-phosphate (G3P)

Fructose-6-phosphate(F6P)

36
Q

The function of Ribose-5-phosphate is?

A

Nucleotide and nucleic acid synthesis

37
Q

The function of the glycolytic intermediates is?

A

Glycolysis

38
Q

The reaction for the oxidative phase is?

A

Glucose-6-phosphate + 2NADP+ +H20> ribose-5-phosphate + CO2 + 2NADPH +2H+

39
Q

The reaction for the non-oxidative phase is

A

6glucose-6-phosphate + 12NADP+ + 6H20> 5glucose-6-phosphate + 12NADPH + 12H+ +6CO2

40
Q

Four functions of PPP are?

A

Production of NADPH for biosynthesis
Formation of ribose-5-phosphate for nucleic acid biosynthesis
A route for the conversion of pentoses to F6P and G3P
Reduces glutathione to maintain RBC membrane integrity

41
Q

The most common inborn error of PPP occurs at the?

A

Oxidative phase of reaction pathway

42
Q

An x-linked recessive hereditary genetic disorder which leads to abnormal low levels of G6PD in the cell is?

A

G6PD deficiency

43
Q

G6PD deficiency affects mainly?

A

RBCs

44
Q

G6PD deficiency causes RBCs to break down prematurely in a process called?

A

Hemolysis

45
Q

The medical condition associated with G6PD deficiency is called?

A

Hemolytic anemia

46
Q

Hemolytic anemia is common in?

A

Africans

Areas where malaria is endemic

47
Q

Hemolytic anemia is caused by?

A

Lipid peroxidation

48
Q

The process by which free radicals “steal” electrons from the lipids in cell membranes, resulting in cell damage is called?

A

Lipid peroxidation

49
Q

G6PD prevents oxidative cellular damage by?

A

Providing substrates

50
Q

G6PD is an enzyme found in the ____ of all cells in the body

A

Cytoplasm

51
Q

Five symptoms of hemolytic anaemia are?

A 
Shortness of breath
Paleness
Muscle pain
Fainting and fatigue
Rapid heart rate etc
52
Q

Five triggering agents of hemolytic anemia in people with G6PD deficiency are?

A

Certain antimalarial drugs eg chloroquine
Certain chemicals eg naphthalene
Analgesics eg aspirin
Infections
Some antibiotics eg sulfonamides & non-sulfur antibiotics

53
Q

An example of sulfonamides is?

A

Sulfamethoxazole

54
Q

Examples of non-sulfur antibiotics are?

A

Nalidixic acid
Dapsone
Isoniazid

55
Q

Fava beans or broad beans cause hemolytic anemia through?

A

Favism

56
Q

A hereditary disorder involving an allergic-like reaction to the broad, or fava, bean

A

Favism

57
Q

Fava beans contain the compounds vicine and convicine which are ____ agents

A

Oxidizing

58
Q

vicine and convicine reduce the RBC____

A

Cell wall

59
Q

Four lab diagnosis of hemolytic anemia are?

A

Haptoglobin estimation
Butler fluorescence test
Lactate dehydrogenase I test
Complete blood count to know the number of RBC

60
Q

Inclusions within red blood cells composed of denatured hemoglobin are called?

A

Heinz bodies or Heinz-Ehrlich bodies

61
Q

An abnormally shaped mature red blood cell with one or more semicircular portions removed from the cell margin is called?

A

A degmacyte or bite cell

62
Q

Treatments for hemolytic anemia include

A

blood transfusions
medicines
plasmapheresis surgery
blood and marrow stem cell transplants and lifestyle changes

Year Two (27 decks)

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