Wednesday, 19 October 2016

NUTRITION  IN PARAMECIUM AND CYCLOSIS

Paramecium is a holozoic in nutrition. It feeds upon bacteria, minute protozoa and organic detritus. The cilia lining the oral groove perform a great role in capturing food particles. During ingestion, the animal move in the direction of food. The cilia present on the peristomial groove beat in such a manner to withdraw food particles in to the peristomial groove. The food particle are collected at the bottom of the gullet and are concentrated into a ball in the endoplasm. These pass through the cytosome to form food vacuoles in the endoplasm, As soon as one food vacuoles detaches form the gullet, anotherone start forming. In the endoplasm, food vacuoles move on a fixed route due to definite streaming movement of the cytoplasm, known as cyclosis. The food vacuoles first travel to the posterior end then take a turn and travel anteriorly, then they pass downwards towards the cytoptge. The food vacuoles undergo changes in size and appearance of the contained food. The endoplasm secretes some enzymes into the food vacuoles which help in the digestion of carbohydrates and proteins. At first digestion occurs in an acidic medium, but later the contents of vacuoles become alkaline. Paramecium cannot digest fats. The undigested food is eliminated from the body through a definite present on the ventral surface posterior to the mouth.

1 comment: