The correct statement in respect of protein haemoglobin is that it

Options

A. Functions as a catalyst for biological reaction
B. maintains blood sugar level
C. acts as an oxygen carrier in the blood
D. forms antibodies and offers resistance to diseases

Answer

C

Explanation

Humans, like all animals, need oxygen. It comes from breathing. About 500 ml of air is drawn into the lungs of an average person with each breath. Only about 3% of the oxygen in blood is dissolved, the rest is chemically bond to haemoglobin `(Hb)` molecules, large positions that contain heme groups embedded in them, Each Hb molecules contains four heme groups, each heme group contains an Fe atom that is able to bind to one `O_(2)` molecule. Thus, a single Hb molecule can bind 4 molecules of `O_(2)`
The entire system of `O_(2)` transport and delivery in the body depends on the pickup and release of `O_(2)` by Hb molecules according to the following series of equilibrium:
`Hb+O_(2)hArrHb(O_(2))`
`Hb(O_(2))+O_(2)hArrHb(O_(2))_(2)`
`Hb(O_(2))_(2)+O_(2)hArr Hb(O_(2))_(3)`
`Hb(O_(2))_(3)+O_(2)hArr Hb(O_(2))_(4)`
The positions of the different equilibria depend on the partial pressures of `O_(2) (P_(O_(2)))` in the various tissues. In hard-working oxygen-starved muscles, where `Po_(2)` is low, `O_(2)` is released from Hb as the equlibria shift toward the left, according to Le Chatelier's principle. In the lungs, where `P_(O_(2))` is high, oxygen is absorbed by Hb as the equilibria shift toward the right.