Digestion in Amoeba with a diagram

Nutrition in an Amoeba occurs through a process called phagocytosis where the entire organism pretty much engulfs the food it plans on eating up. The mode of nutrition in amoeba is known as holozoic nutrition. It involves the ingestion, digestion and egestion of food material.

Amoeba does not have any specialized organ for nutrition. Its entire process is carried through the body surface with the help of pseudopodia.

Explanation:

Holozoic nutrition is the process of nutrition that takes place in organisms which take solid or liquid food inside their body. Amoeba follows holozoic nutrition.

Holozoic nutrition in amoeba takes place in the following steps:

Ingestion

Ingestion is the process of taking in the food into the body either by swallowing or absorbing it. Amoeba pushes out the pseudopodia to encircle the food and engulfs it forming a food vacuole. This process is known as phagocytosis.

Digestion

Digestion is the process of breaking the insoluble and large food molecules into soluble and minute molecules. In amoeba, the food vacuoles are transported deeper into the cell and with the help of the digestive enzymes, the large insoluble particles are broken down to the simplest molecules.

Absorption

In this process of absorption, the nutrients from the digested food material are absorbed into the cell’s cytoplasm by leaving behind the undigested particles. This process is called diffusion. The excess food is stored in the form of glycogen and lipids.

Assimilation

Assimilation is the process of obtaining energy from the absorbed food molecules. In amoeba, absorbed food molecules are utilized for producing the energy required to carry out different life processes within the cell.

Egestion

Egestion is the process of excretion of undigested food material. In amoeba, this process is carried out by rupturing the cell membrane to remove the undigested food material from its body.

step 1: initiation

initiation is the beginning of transcription. it occurs when the enzyme rna polymerase binds to a region of a gene called the promoter. this signals the dna to unwind so the enzyme can ‘‘read’’ the bases in one of the dna strands. the enzyme is now ready to make a strand of mrna with a complementary sequence of bases.

step 2: elongation

elongation is the addition of nucleotides to the mrna strand. rna polymerase reads the unwound dna strand and builds the mrna molecule, using complementary base pairs. there is a brief time during this process when the newly formed rna is bound to the unwound dna. during this process, an adenine (a) in the dna binds to an uracil (u) in the rna.

step 3: termination

termination is the ending of transcription, and occurs when rna polymerase crosses a stop (termination) sequence in the gene. the mrna strand is complete, and it detaches from dna.