Oxygen Transport

Question 1

The maximum number of oxygen transported by one haemoglobin is
A. 1
B. 2
C. 3
D. 4
E. 5

Answer 1

D 4

Question 2

What is the Bohr effect?
A. Increased affinity of haemoglobin for oxygen in low pH
B. Decreased affinity of haemoglobin for oxygen in low pH
C. Increased affinity of haemoglobin for oxygen at increased
temperature
D. Decreased affinity of haemoglobin for oxygen at increased
temperature
E. Increased affinity of haemoglobin for oxygen at increased
carbon dioxide concentrations

Answer 2

B Bohr effect occurs when hypoxic tissues release H+ decreasing the pH. This lowered pH makes the RBCs affinity curve shift to the right, thus lowering the affinity for oxygen. thus releasing O2 into the hypoxic tissues

Question 3

Haemoglobin is more likely to release oxygen when
A. There is a decrease in temperature
B. pH is more alkaline
C. There is a decrease in partial pressure of oxygen
D. The is an increase in the partial pressure of oxygen
E. There is a decrease in partial pressure of carbon dioxide

Answer 3

C. Hb releasing O2 when the partial pressure outside decreases

Question 4

Most of the oxygen transported by the blood is
A. dissolved in plasma.
B. bound to hemoglobin.
C. in ionic form as solute in the plasma.
D. bound to a plasma protein.
E. carried by white blood cells.

Answer 4

B 98.5% bound to Hb and 1.5% dissolved in plasma

Question 5

Which of the following is true in regards to Fetal Haemoglobin?
A. Fetal Haemoglobin does not release oxygen when the pH is low
B. Fetal Haemoglobin does not release oxygen when the partial pressure of carbon dioxide is high
C. Adult Haemoglobin has a greater affinity for oxygen than fetal Haemoglobin
D. The structure of fetal Haemoglobin is different to Haemoglobin in the adult. It has a greater affinity for oxygen
E. Fetal Haemoglobin has the same structure as Haemoglobin in the adult

Answer 5

D Foetal Hb needs to have a higher affinity in order to make a partial pressure gradient to the maternal blood

It does this through the usage of Gamma subunits instead of Beta to have a structure that conformationally favours an increased affinity for Hb

Question 6

Sean Murphy, aged29, is the opening batsmen in his cricket team. He hits the ball to the boundary but it is fielded by an opposition player. He runs hard to ensure he gets 3 runs. Haemoglobin plays a crucial role in ensuring he has enough oxygen during the game.
1.Explain how the loading and unloading of O2 is facilitated by change in the shape of Haemoglobin

Answer 6

As O2 binds Hbs affinity for O2 increases

As O2 releases Hbs affinity for O2 decreases, releasing O2 into tissue

Question 7

When sprinting (exercising heavily) explain 3 factors that would decrease the Haemoglobins affinity for O2

Answer 7

1. The raising Temperature
2. Increasing H+ levels (decreasing pH)
3. Increasing CO2 levels

Question 8

What is the role of BPG in blood (hypoxic tissue)

Answer 8

When exposed to hypoxic tissue, RBCs produce BPG to bind to positions on Hb to reduce O2 Affinity, releasing more O2 into the hypoxic tissues

Question 9

What effect does high altitude have on Hb Saturation given normal = 100mmHg and high alt = 80mmHg

Answer 9

Saturation goes from 98% to 95% this is due to the sigmoidal curve