Lecture 9 & 10 - Hemoglobin I & II Flashcards Preview

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Flashcards in Lecture 9 & 10 - Hemoglobin I & II Deck (29):
1

Two components necessary for Hb production

Vit. B6 and Iron

2

Two things necessary for DNA synthesis

Vit. B12 and Folic acid

3

Lack organelles, biconcave (utilizing spectrin), anucleated.

Mature red blood cells

4

Explain why the biconcave shape is important for RBCs

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.

5

Transferrin f(x)

"Salvage" iron from damaged/lysed blood cells

6

F(x) of haptiglobin

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

7

Each hemoglobin chain is comprised of ____ alpha-domains.

8

8

Acts to bind oxygen in the Hb molecule

Proximal (or "E7") Histidine

9

Binds to Iron in Hb molecule

Distal (or "F8") Histidine

10

Vast majority of adult hemoglobin

Hemoglobin-Alpha

11

Small % of adult hemoglobin

Hb-A2

12

Structure of Hb-A

2 alpha subunits; 2 beta subunits

13

Structure of Hb-A2

2 alpha subunits; 2 delta subunits

14

Structure of fetal hemoglobin (Hb-F)

2 alpha subunits; 2 gamma subunits

15

Number of Fe2+ per Hb subunit.

1 (total of 4 in the complete Hb molecule)

16

Domains of Hb that form the "pocket" for Fe

EFG

17

What oxidative state does iron take in Hb?

Fe2+

18

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

Distal histidine (E7)

19

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

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

20

Binding of oxygen to Hb is under _____ control.

allosteric

21

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

What is "allosteric?"

22

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

2+

23

What is meant by "Hemoglobin is cooperative?"

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

24

Compare/contrast Hb and Mb

A image thumb
25

What molecules inhibit oxygen binding to Fe2+?

Hydrogen ions 2,3-BPG CO2

26

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

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

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

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

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

2,3-BPG (allows more oxygen offloading)

29

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

Increased: H+ CO2 2,3-BPG