Question

how is undigested food is thrown out in amoeba

Answer 1

it forms a food vacuole and then the food just swiftly moves out of the body of the unicellular organism

Answer 2

Digestion in amoeba is intracellular taking place within the cell. The food taken in remains in a food vacuole or gastric vacuole formed by the cell membrane and small part of the cytoplasm. The vacuoles are transported deeper into the cells by cytoplasmic movements. Here they fuse with lysosomes that contain enzymes. Two enzymes amylase and proteinase have been reported. Thus, amoeba can digest sugars, cellulose and proteins. Fats, however, remain undigested.

The contents of the vacuole become lighter and the outline of the vacuole becomes indefinite indicating that the digestion is complete.

Since the food on digestion is converted into liquid diffusible form, it is readily absorbed by the cytoplasm. The vacuole becomes progressively smaller as the food is absorbed by diffusion.