Lecture 9 & 10 - Hemoglobin I & II Flashcards

1
Q

Two components necessary for Hb production

A

Vit. B6 and Iron

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2
Q

Two things necessary for DNA synthesis

A

Vit. B12 and Folic acid

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3
Q

Lack organelles, biconcave (utilizing spectrin), anucleated.

A

Mature red blood cells

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4
Q

Explain why the biconcave shape is important for RBCs

A

Through spectrin, the plasma membrane of RBCs have a high ability to deform. This is important because the diameter of capillaries are often smaller that the diameter of RBCs.

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5
Q

Transferrin f(x)

A

“Salvage” iron from damaged/lysed blood cells

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6
Q

F(x) of haptiglobin

A

Salvage Hb and excrete in bilirubin (prevents free heme from causing oxidative stress to the body)

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7
Q

Each hemoglobin chain is comprised of ____ alpha-domains.

A

8

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8
Q

Acts to bind oxygen in the Hb molecule

A

Proximal (or “E7”) Histidine

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9
Q

Binds to Iron in Hb molecule

A

Distal (or “F8”) Histidine

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10
Q

Vast majority of adult hemoglobin

A

Hemoglobin-Alpha

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11
Q

Small % of adult hemoglobin

A

Hb-A2

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12
Q

Structure of Hb-A

A

2 alpha subunits; 2 beta subunits

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13
Q

Structure of Hb-A2

A

2 alpha subunits; 2 delta subunits

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14
Q

Structure of fetal hemoglobin (Hb-F)

A

2 alpha subunits; 2 gamma subunits

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15
Q

Number of Fe2+ per Hb subunit.

A

1 (total of 4 in the complete Hb molecule)

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16
Q

Domains of Hb that form the “pocket” for Fe

A

EFG

17
Q

What oxidative state does iron take in Hb?

A

Fe2+

18
Q

Binds to oxygen and results in a “barrier” to formation of carboxy-Hb

A

Distal histidine (E7)

19
Q

The Bohr Effect promotes oxygen release in tissues by what mechanism?

A

Allosteric effect of incr. [H+] and incr. [CO2]

20
Q

Binding of oxygen to Hb is under _____ control.

A

allosteric

21
Q

This type of control deals with a molecule binding other than at an enzyme/protein active site to change a conformation.

A

What is “allosteric?”

22
Q

Iron exists in the ____ state to prevent generation of free radicals.

A

2+

23
Q

What is meant by “Hemoglobin is cooperative?”

A

The binding of one molecule to a Hb subunit causes a conformational in the other subunits.

24
Q

Compare/contrast Hb and Mb

A
25
Q

What molecules inhibit oxygen binding to Fe2+?

A

Hydrogen ions 2,3-BPG CO2

26
Q

What is the mechanism behind the offloading of oxygen as a result of increased hydrogen ion []? (In regard to O2-Hb dissociation curve)

A

Increased [H+] results in a right shift of the oxygen-Hb dissociation curve; this is due to oxygen having less affinity for Hb in acidic environments (actively metabolizing tissue)

27
Q

What is the mechanism behind the right shift of the oxygen-Hb dissociation curve in increased [CO2] levels?

A

Increased CO2 levels are found in actively metabolizing tissues. As a result, increased CO2 produces a rightward shift of Oxygen-Hb curve, which means that the oxygen dissociates (“offloads”) freely from Hb in high [CO2]

28
Q

This molecule maintains the Hb in the T-state, preventing any binding of Oxygen to Hb

A

2,3-BPG (allows more oxygen offloading)

29
Q

3 molecules producing a right shift of the oxygen-Hb dissociation curve

A

Increased: H+ CO2 2,3-BPG