Question

In Ascaris , the respiration is
A. Aerobic
B. Anaerobic
C. Both (A) and (B)
D. Coelomic

Answer 1

Hint: Ascaris is commonly called round worm and is very common in the small intestine of man. In the small intestine of humans availability of oxygen is limited. Anaerobic respiration occurs in the absence of oxygen and aerobic respiration takes place in presence of oxygen.

Complete answer:
Ascaris is one of the most famous end parasites of man. It also infects Sheep, pigs and cattle. It lives in the small intestine, is more common in children than adults, and can eat the host's half-digested food.
Only one host is required by Ascaris to complete its life cycle intermediate hosts are not required.

>Anaerobic respiration: In Ascaris respiratory organs are absent but the parasites breathe anaerobically , because the oxygen level in the host's intestines is very low. Energy is obtained by breaking down glycogen into Carbon dioxide and fatty acids, which are excreted through the cuticle.
>Aerobic respiration: It also consumes oxygen whenever possible. Small amounts of haemoglobin is present in the body walls and in cell fluid can scavenge oxygen and induce aerobic respiration.
So in Ascaris generally anaerobic respiration occurs as oxygen is in limited amounts in the intestine of the host but when oxygen is present they also respire aerobically.

Hence, the correct answer is option (C).

Note: Ascariasis is a human disease caused by the parasitic Ascaris lumbricoides. About a quarter of the world's population can be infected. Ascariasis is very common in tropical and subtropical regions with poor hygiene. Other species of the genus Ascaris can cause diseases in domestic animals, such as B. Ascaris suum, which affects pigs. Several genes have been identified that may increase susceptibility to infection in humans. Ascaris belongs to phylum Aschelminthes. Ascaris shows sexual dimorphism. In Ascaris anaerobic respiration occurs through glycolysis in which incomplete oxidation of food occurs in the absence of oxygen.