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Flashcards in 9. Hemoglobin Deck (20):
1

Hemoglobin is composed of

4 polypeptide subunits
2α and 2β
1 heme in every polypetptide

2

hemoglobin (hb) is exists in how many and which forms

2 forms
T form and R form

3

hemoglobin (hb) - T form properties

Taut form deoxygenated low affinity for O2

4

hemoglonim ( hb ) - R form properties

relaxed
oxygenated
high affinity for O2 ( x300)

5

hb - properties

1. positive cooperativity
2. negative allostery

6

hemoglobin (hb) - positive cooperativity

tetrameric Hb molecule can bin 4 O2 molecules and has higher affinity for each subsequent O2 molecule bound

7

substance that favor taut form over relaxed dorm ( shift curve to right)

INCREASED CL-, H+, CO2, 2,3 BPG, temperature

8

fetal hemoglobin subunits

2α and 2γ

9

fetal hemoglobin vs adult ( about funtion

lower affinity for 2.3 - BPG than adult hemoglobin and thus higher affinity for O2

10

hemoglobin also act as

a buffer for H+ ions

11

buffer for H+ ions

hemoglobin

12

How many polypeptide subunits make up hemoglobin?

Four

13

What are the two conformational forms of hemoglobin?

Relaxed (oxygenated) and taut (deoxygenated)

14

• Of the two forms of hemoglobin, the taut (T) form has ____ (high/low) affinity for oxygen. The relaxed (R) form has ____ (high/low) affinity.

Low; high (300 times more affinity in R form) (Taut in Tissues, Relaxed in Respiratory tract)

15

Does hemoglobin have positive or negative cooperativity with respect to oxygen binding and affinity?

Positive

16

Does hemoglobin have positive or negative allostery with respect to oxygen binding and affinity?

Negative

17

An increase in which five factors will favor the taut form of hemoglobin over the relaxed form and will decrease affinity for oxygen?

Chloride (Cl-), protons (H+), carbon dioxide, 2,3-bisphosphoglycerate, and temperature

18

A patient is exercising in the freezing cold. He is otherwise healthy. Is his hemoglobin more likely to be taut or relaxed?

Taut, as exercise (generating CO2) favors the taut form (the outside temperatures are meaningless, as body temperature is what matters)

19

Fetal hemoglobin has ____ (higher/lower) affinity for 2,3-BPG than does adult hemoglobin, causing ____ a (higher/lower) affinity for oxygen.

Lower, higher

20

Hemoglobin can act as a buffer for which ions?

H+