Chapter 17 (Pt. 3)

Question 1

how does temperature affect Hb affinity for O2?

Answer 1

temperature alters structure, thus increase temperature decreases Hb affinity for O2.

when exercising, body temperature increases when making ATP, right shift, lower affinity

Question 2

how does pH affect Hb affinity for O2?

Answer 2

decreased pH = decreased Hb affinity

Question 3

how does CO2 affect Hb affinity for O2?

Answer 3

increased metabolic activity = increased Co2

CO2 binds to amino groups

carbamino-Hb assumes “tense-like” state = lower affinity for O2 than Hb did.

binding CO2, not O2 = decreased affinity

Question 4

how does 2,3 bisphosphoglycerate affect Hb affinity for O2?

Answer 4

2,3 BPG binds to Hb

Hb assumes tense-like state

decreased affinity for O2, can’t stay in relaxed state

Question 5

how does the Bohr effect affect Hb affinity for O2?

Answer 5

decreased pH = decreased Hb affinity

Question 6

HOW does carbamino-Hb affect Hb affinity for O2?

Answer 6

increased metabolic activity = increased CO2

CO2 binds to amino groups

carbamino-Hb assumes “tense-like” state = lower affinity for O2 than Hb did.

binding CO2, not O2 = decreased affinity

Question 7

how does the Haldane effect affect Hb affinity for O2?

Answer 7

increased metabolic activity = increased Co2

CO2 binds to amino groups

carbamino-Hb assumes “tense-like” state = lower affinity for O2 than Hb did.

binding CO2, not O2 = decreased affinity

Question 8

increased Hb affinity for O2: right or left shift?

Answer 8

left

Question 9

decreased Hb affinity for O2: right or left shift?

Answer 9

right

Question 10

right shift: increased or decreased Hb affinity for O2?

Answer 10

decreased

Question 11

left shift: increased or decreased Hb affinity for O2?

Answer 11

increased

Question 12

why does a lower pH decrease hemoglobin affinity for O2?

Answer 12

lower pH = more H+

histidine (near C terminus of globin protein) grabs an H+ and gains a full (+) charge

(-) aspartic acid nearby attracts to (+) and locks Hb in “tense-like” state to prevent cooperative binding

less affinity for O2

Question 13

why does CO2 decrease Hb affinity for O2?

Answer 13

CO2 binds to amino groups at the N terminals of the 4 Hb subunits

and at internal arginine and lysine AAs

Hb conformational change, converted into “tense-like state”

carbamino Hb has a lower affinity for oxygen than Hb

Question 14

why does 2,3 bisphosphoglycerate lower Hb affinity for O2?

Answer 14

2,3 BPG binds to Hb and locks Hb in a tense-like state

Question 15

under what conditions does 2,3 BPG activity increase? (3)

Answer 15

low O2 levels.

• anemia
• high altitude
• during pregnancy

Question 16

why do O2 levels drop in anemia?

Answer 16

not enough RBCs

Question 17

why do O2 levels drop in high altitude?

Answer 17

not enough O2 to saturate Hb, even if you do have enough RBCs

Question 18

why do O2 levels drop during pregnancy?

Answer 18

mom is breathing for two

Question 19

what direction would 2,3 BPG shift the curve of Hb for O2?

Answer 19

right

Question 20

why is overproduction of 2,3 BPG advantageous under hypoxia conditions?

Answer 20

allows for more O2 to be released and go to hypoxic tissues

Question 21

non-enzymatic glycation increases/decreases Hb affinity for O2 and increases/decreases O2 delivery to tissues

Answer 21

increases; decreases