Question

why is diffusion insufficient to meet the oxygen requirement of multicellular organisms like humans

Answer 1

in multicellular organisms all cells r not exposed to aur and there are millions of cells this simple diffusion is not useful....and if we were to rely on diffusion then it would take three years for an oxygen to reach from the head to the toe

Answer 2

DIFFUSION :-

Diffusion is a process in which the gaseous movement takes place from a region of higher concentration to a region of lower concentration.

Multicellulars don't depend on Diffusion.

That is most of their work is not driven by the process of Diffusion.

Diffusion is considered as a slow process.

This means that the requirement of time for Diffusion to take place is very high.

Diffusion requires the lot of time for the gaseous exchange.

But,

The multicellular creatures like human beings have a very complex body.

Their body structure is so Complex that they require oxygen constantly.

so,

For the transportation of oxygen to all cells of their body they cannot afford such a long period of time which is taken by diffusion.

so,

To make the process faster our blood has hemoglobin which dissolves the oxygen to form Oxy-Hemoglobin.

Oxy - hemoglobin transports the oxygen to different cells of the body.

As we discussed,

Diffusion is a very very slow process and it requires a huge amount of time for the gaseous exchange.

The body cannot afford such a delay.

Because such delay may lead to even death as the cells won't get oxygen in time.

Moreover,

Scientists have proved that it will take around 3 years for the oxygen to reach our feet from the head by the process of diffusion.

This gives a crystal clear evident that Diffusion cannot satisfy the multicellular's need of oxygen constantly and quickly.

This is the reason why diffusion is not used as a respiratory carrier for carrying oxygen to different parts of the multicellular body.

• Thus, we can say that diffusion is insufficient for fulfilling the oxygen requirements of a multicellular like human being which possess complex body structure and requires constant oxygen and quick transportation of oxygen.

Thanks!