METABOLISM Flashcards

1
Q

Two sites on the Hgb molecule
which are prone to oxidation:

A
  1. Iron atom (heme)
  2. Sulfhydryl groups (globin)
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2
Q

RBC relies on________________ for its energy.

A

anaerobic glycolysis

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3
Q

❖ RBC metabolic processes requiring energy:

A

 Intracellular cationic gradient maintenance
 Maintenance of membrane phospholipid distribution
 Maintenance of skeletal protein deformability
 Maintenance of functional hemoglobin with ferrous iron
 Protecting cell proteins from oxidative denaturation
 Glycolysis initiation and maintenance
 Glutathione synthesis
 Nucleotide salvage reactions

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4
Q

principal source of energy

A

Glucose

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5
Q

Other sources of energy

A

galactose, fructose, and mannose

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6
Q

RBC membrane is permeable to what energy sources

A

glucose

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7
Q

RBC membrane is NOT permeable to what energy sources

A

sucrose, lactose, and maltose

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8
Q

90-95 % of glucose – metabolized by the

A

Embden-Meyerhof pathway (EMP)

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9
Q

5-10 % of glucose – metabolized by the

A

Hexose Monophosphate Shunt (HMP)/Pentose Phosphate Shunt
(PPS)

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10
Q

 Major source of RBC energy | 90% Anaerobic glycolysis
 Requires glucose for energy production

A

Embden-Meyerhof Pathway

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11
Q

Embden-Meyerhof Pathway Maintains cellular energy by generating

A

2 ATP molecules

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12
Q

most common deficiency in the E-M pathway

A

PK (pyruvate kinase) deficiency

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13
Q

Rate of glycolysis ↑ when there is

A

↑ in the intracellular pH (hypoxia)

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14
Q

Rate of glycolysis ↓ when

A

ATP levels ↑ and
vice versa

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15
Q

 Maintains membrane proteins & lipids, enzymes, hemoglobin iron in its ferrous state
 Prevents denaturation of Hb molecule by oxidation

A

Hexose Monophosphate Shunt/ Oxidative Pathway/
Pentose-Phosphate Pathway

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16
Q

What enzyme in the Hexose Monophosphate Shunt reduces NADP to NADPH?

A

G6PD (Glucose-6-phosphate dehydrogenase)

17
Q

What is the primary function of the Hexose Monophosphate Shunt/Pentose Phosphate Pathway in red blood cells?

A

Maintains membrane proteins, lipids, enzymes, and hemoglobin iron in its ferrous state.

18
Q

Reduces toxic peroxide to water and oxygen, protecting hemoglobin from oxidation

A

reduced glutathione (GSH)

19
Q

Which enzyme is responsible for converting oxidized glutathione (GSSG) to reduced glutathione (GSH)?

A

Glutathione reductase

20
Q

What condition results from a G6PD deficiency and leads to the formation of denatured globins?

A

Heinz bodies

21
Q

What is the toxic effect of peroxide in red blood cells?

A

It oxidizes hemoglobin iron from Fe2+ to Fe3+, damaging the globin proteins.

22
Q

provides the only means
of generating NADPH.

A

G6PD

23
Q

oxidized heme unable to carry O2

A

methemoglobin

24
Q

Maintenance of the iron in its FERROUS state by which enzymes

A

methemoglobin reductase/cytochrome
b5 reductase

25
Q

in the presence of methemoglobin reductase converts ferric iron → ferrous iron

A

NADPH

26
Q

Generates 2,3 DPG w/c regulates O2 delivery to tissues by competing w/ O2 for the O2 binding site of Hb

A

Rapoport-Luebering Pathway

27
Q

↑ 2,3-BPG: ↓ Hb affinity to O2 →

A

↑ Tissue oxygenation

28
Q

↓ 2,3-BPG: ↑ Hb affinity to O2 →

A

↓ Tissue oxygenation

29
Q

Any deficiency in the Embden Meyerhof Pathway glycolytic enzymes results to what group of diseases

A

Hereditary nonspherocytic hemolytic anemia

30
Q

Part ng bone marrow na inoopen up ni EPO

A

reticular adventitial cells