Topic 4 -16

Question 1

What is the primary role of haemoglobin (Hb) in red blood cells?

Answer 1

To transport O2

Question 2

What does the sigmoid oxygen dissociation curve of haemoglobin represent?

Answer 2

The percentage saturation of Hb with O2 in relation to the availability of O2

Question 3

Why is the oxygen dissociation curve of haemoglobin S-shaped (sigmoid)?

Answer 3

Because binding is cooperative

Question 4

What happens to the percentage saturation of Hb when there is a small increase in the partial pressure of oxygen (pO2)?

Answer 4

It causes a disproportionately large increase in percentage saturation

Question 5

What is the affinity of Hb for O2 when the partial pressure is high?

Answer 5

Very high

Question 6

What occurs when there is a small decrease in pO2 affecting oxygenated blood in tissues?

Answer 6

It causes a disproportionately large decrease in percentage saturation of Hb

Question 7

What distinguishes myoglobin (Mb) from haemoglobin (Hb) in terms of structure?

Answer 7

Myoglobin has one subunit, while Hb has four subunits

Question 8

Does myoglobin exhibit cooperative binding?

Answer 8

No

Question 9

What is the primary function of myoglobin?

Answer 9

Acts as an O2 store

Question 10

How does fetal haemoglobin (HbF) differ from adult haemoglobin (Hb) in terms of affinity for O2?

Answer 10

Fetal Hb has a higher affinity for O2

Question 11

What is the significance of fetal Hb’s high affinity for O2?

Answer 11

It allows the fetus to take O2 from its mother

Question 12

What is the Bohr effect?

Answer 12

The effect of CO2 on the O2 dissociation curve of Hb

Question 13

What happens to Hb’s affinity for O2 when CO2 levels are high?

Answer 13

Hb binds with O2 less well (reduced affinity)

Question 14

What occurs in the lung capillaries where CO2 levels are low?

Answer 14

Hb binds with O2 more easily (increased affinity)

Question 15

Fill in the blank: Myoglobin has a _______ affinity for O2, unaffected by partial pressure.

Answer 15

very high

Question 16

How many O2 molecules can haemoglobin carry at maximum?

Answer 16

4

Question 17

How many O2 molecules can myoglobin carry at maximum?

Answer 17

1

Question 18

True or False: Fetal haemoglobin exhibits cooperative binding.

Answer 18

Yes

Question 19

What is the effect of high CO2 levels on the O2 saturation of Hb?

Answer 19

It decreases the O2 saturation

Question 20

What is the effect of low CO2 levels on Hb’s ability to bind O2?

Answer 20

It increases the ability to bind O2