Question

Which activity is illustrated in the diagram of an amoeba shown below?

(a) Ingestion
(b) Digestion
(c) Egestion
(d) Assimilation

Answer 1

Hint: For the maintenance of health and the growth and development nutrition is required in an organism. The mode of nutrition differs among the different organisms. In the case of amoeba with the help of pseudopodia, the food is engulfed completely inside the cell.

Complete answer:
Nutrition is a process by which an organism takes up food and utilizes it to get energy, for growth, repair, maintenance, and excrete the waste from the body. In amoeba, the holozoic mode of nutrition is found as it doesn’t have any well-designed organ for eating food so it uses pseudopodia. Its entire process in the amoeba is carried out through a false project of its body surface called pseudopodia. In Amoeba the entire food is engulfed through the pseudopodia, this process is known as phagocytosis.
The process involved in the mode of nutrition in amoeba involves the following stages:
- Ingestion
- Digestion
- Absorption
- Assimilation
- Egestion
Ingestion: Ingestion is the process of taking in the food either by swallowing or absorbing. The food in the amoeba is encircled through pseudopodia and then is completely engulfed forming a food vacuole known as phagocytosis.
Digestion: It is the process where the large food particles are broken down into a simpler substance that will easily soluble. The food is then carried deep inside where several digestive enzymes will act upon it and break them into simpler molecules.
Absorption: The cell cytoplasm will undergo diffusion, where the nutrients are absorbed from the digested food material. The food is stored after utilization in the form of lipids and glycogen while the particles that are undigested will not be absorbed.
Assimilation: The absorbed food molecule in the amoeba is utilized for producing the energy required to carry out the different life processes inside the cell.
Egestion: It is the process in which the unwanted, unabsorbed, and the undigested food is excreted out of the body. The excretion occurs through the rupturing of the cell membrane which will result in the release of the waste products.

So, the correct answer is ‘Ingestion’.

Note:
Holozoic type of nutrition is a type of heterotrophic nutrition where the organism can’t produce energy on its own. The parasitic organisms obtain their nutrition from other organisms without killing them while the saprophytic organisms absorb nutrition from the dead organisms.