Myoglobin & Hemoglobin

Question 1

An increase in pCO2 causes hemoglobin’s affinity for oxygen to
● increase
● decrease
● stay the same

Answer 1

↑PCO2 ↓PO2= decrease affinity to oxygen

↓PCO2 ↑ PO2 = increase affinity to oxygen

Question 2

The absence of 2,3-BPG causes hemoglobin’s affinity for oxygen to *

● increase
● decrease
● stay the same

Answer 2

↑ 2,3BPG= decrease affinity to oxygen
↓ 2,3BPG= increase affinity to oxygen

Question 3

Myoglobin’s secondary structure is primarily composed of *

● alpha helices
● beta helices
● polyproline helices
● none of the above

Answer 3

Alpha helices

Question 4

Carbon monoxide binds to heme *
● with higher affinity than oxygen
● with lower affinity than oxygen
● results in the oxidation of iron in the ferrous to the ferric state
● displaces carbon dioxide resulting to poisoning

Answer 4

with higher affinity than oxygen

Question 5

Which of the following increases the affinity of hemoglobin for 02 *
● an increase in pH
● a decrease in pH
● an increase in o2 concentration
● an increase in 2,3 BPG

Answer 5

Increase in pH

Question 6

The Bohr effect refers to *
● the decrease in affinity of Hb for 02 when the pH goes down
● the decrease in affinity of Hb for 02 when the pH goes up
● the decrease in affinity of Hb for 02 when the BPG concentration goes down
● the decrease in affinity of Hb for 02 when the BPG concentration goes up

Answer 6

the decrease in affinity of Hb for O2 when the pH goes down.

Question 7

The rearrangement of T state hemoglobin to the R state *
● involves the movement of the Fe(Il) into the heme plane
● opens a central cavity for BPG binding
● occurs in each protein subunit independently when its heme binds oxygen
● requires the binding of at least three oxygen molecules

Answer 7

This movement occurs when oxygen binds to heme, causing a conformational change that shifts hemoglobin from the tense (T) state to the relaxed (R) state, increasing its affinity for additional oxygen.

involves the movement of the Fe(II) into the heme plane

Question 8

BPG stands for *
● bisphosphoglycerate
● bisphenylglycerol
● biphenylglycine
● betapropylglutamine

Answer 8

bisphosphoglycerate

Question 9

The reaction of carbonic anhydrase catalyzes *

● the hydration of carbon dioxide, forming bicarbonate and protons
● the reduction of carbon dioxide with the concomitant consumption of protons
● the hydrolysis of carbamates with the concomitant consumption of protons
● the formation of carbamates with the concomitant release of protons

Answer 9

the hydration of carbon dioxide, forming bicarbonate and protons.

This reaction is essential for maintaining acid-base balance in the body and facilitating the transport of carbon dioxide in the blood.

Question 10

In sickle-cell anemia, the negatively charged glutamic acid residue is replaced by the neutral amino acid
● • valine
● • tyrosine
● • glycine
● • lysine

Answer 10

Valine