Q.(a) State the form in which the following are stored:(i) Unused carbohydrates in plants.(ii) The energy derived from food in humans,(b) Describe the process of nutrition in Amoeba with the help of diagram. (Board Term I, 2016)

Solution :

(a) ( i )  Unused carbohydrates are stored in plants as starch, a complex sugar. When energy is required, they are later converted into simple sugars (glucose).

(ii) The molecules of the food that are absorbed contain energy in their chemical bonds. Oxidation in the cell releases the bond energy between them. To create ATP (adenosine triphosphate) molecules, bonds between ADP (adenosine diphosphate) and inorganic phosphate (Pi) are formed.  These bonds are later broken by enzymatic hydrolysis and the energy released is utilised for cellular processes.

(b) An amoeba is a single-celled organism. Amoeba consumes aquatic, microscopic organisms that float. Holozoic nutrition is the mode of nutrition in amoeba. Phagocytosis refers to the action of an amoeba obtaining food.

Ingestion : Amoeba ingests food particles by creating brief pseudopodia, or finger-like projections, around them as they approach it. Inside the amoeba, the food is enclosed in a food vacuole along with a small amount of the surrounding water.

Digestion : Breakdone of food by the enzymatic action.

Absorption : By diffusion, the food is immediately absorbed into the cytoplasm of the amoeba cell after being digested by digestive enzymes inside the food vacuole.

Assimilation : Spreading th absorbed nutrient throughout the cytoplasm.

Egestion : When considerable amount of undigested food collects inside Amoeba then its cell membrane ruptures at any place to throw out this undigested food. This process is called egestion.

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