Chapter 13 (Gaseous Exchange) F.Sc 1st Year Biology Short Questions

What changes occur in an animal during diving reflex?

When a mammal dives to its limit the diving reflex is activated. The breathing · stops, the rate of heart beat slows down to one tenth of the normal rate, the consumption of oxygen and energy is reduced. The blood is redistributed but most of the blood goes to the brain and heart which can least withstand to anoxia. Skin muscles and digestive organs and other internal organs receive very little blood while an animal is submerged because these areas can survive with less oxygen, Muscles shift from aerobic to anaerobic respiration.

How respiration takes place through cork tissue.

In the older parts of the plant i.e., both stems and roots, there is present cork tissue which is formed of dead cells and has special pores called lenticels which are involved in gaseous exchange.

How haemoglobin help in the transport of oxygen?

Hemoglobin readily combines with oxygen to form oxyhemoglobin in the condition of high oxygen concentration and atmospheric pressure. At tissue lits back to its Haemoglobin giving out most of its oxygen to surrounding cells which have low oxygen concentration and less pressure.[the_ad id=”17150″]

What are causes of lung cancer?

The chances of lung cancer are ten times more in those persons who smoke or live in smoky and congested (crowded) areas as compared to those who do not smoke. It is now estimated that 90% of lung cancer is caused by smoking. Recent research indicates that more than ten compounds of tobacco smoke are involved to cause cancer.

How do spiracles differ from tracheoles?

The main tracheal trunk of cockroach communicates with exterior by paired apertures called spiracles present in the sides of the body. The main tracheae divide and subdivide forming very fine tubules called tracheoles.

How is carbon dioxide absorbed by the cell walls of mesophyll cells?

It is absorbed by simple diffusion because its concentration in mesophyll cells is lower than air spaces of leaf.

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