Question

Oxygen carrying capacity of blood is?
A. 20%
B. 30%
C. 40%
D. 50%

Answer 1

Hint:- Oxygen carrying capacity of blood is defined as the amount of oxygen which blood can carry to transport. In 100 ml of blood, there is 15 grams of haemoglobin.

Complete step-by-step solution:-
First of all, you should know what oxygen carrying capacity is. Oxygen carrying capacity of blood means the amount of oxygen which is transported by the blood and the normal haemoglobin content in blood is 15 gram.
So, the normal haemoglobin content in blood is 15 gram and the oxygen carrying capacity of haemoglobin is 1.34 ml oxygen per gram Hb and therefore blood with 15 gram of haemoglobin should carry 20.1 ml of oxygen. It means the haemoglobin carry 20.1 ml of oxygen in 100 ml of the blood.
But, 20 ml of oxygen is carried by blood with 15 g of haemoglobin and the oxygen carrying capacity of blood is 20% since the haemoglobin is not fully saturated with oxygen but it is only saturated about only 95%. Thus, oxygen carrying capacity of blood is 20%.
If we look at options now, Option A is 20%. It is the correct option since the oxygen carrying capacity of blood is 20% as the normal haemoglobin content in blood is 15g and for haemoglobin, the oxygen carrying capacity is 1.34 ml/g. Thus this option is the correct one.
Moving to option B which is 30%. It is an incorrect option since the oxygen carrying capacity of blood is 20% not 30% which makes it an incorrect option and therefore it gets eliminated.
Moving to option C which is 40%. It is an incorrect option since the oxygen carrying capacity of blood is 20% not 40% which makes it an incorrect option and therefore it gets eliminated.
Last option D is 50%. It is an incorrect option since the oxygen carrying capacity of blood is 20% not 50% which makes it an incorrect option and therefore it gets eliminated.
Thus, the correct answer is option A which is 20%

Note:- Since there is a presence of 5 gram of haemoglobin in 100 ml of blood, oxygen carrying capacity for haemoglobin is 1.34 ml oxygen per gram of Hb and thus 100 ml of blood has capacity to bind 20.1 ml of oxygen. Thus, the oxygen carrying capacity of blood is 20%.