Tag: biology

• The starch, proteins and fats in food get digested by digestive enzymes and get converted into simpler components and this type of digestion is called extracellular digestion.
• The starches and some glycogen in food get hydrolysed inside the mouth while the food is swallowed by ptyalin or salivary amylase enzyme in the saliva.
  
• So, the correct answer is 'All of the above'.

In Planaria, digestion involves both the modes, ie, extracellular as well as intracellular. Fats are normally digested extracellularly, while other food components are digested intracellularly.
The intracellular digestion is done by amoeboid cells lining the intestine. Digested food diffuses to the surrounding mesenchyme. 

Hydra exhibits both extracellular digestion (in the gastrovascular cavity) and intracellular digestion (in the cells lining the cavity).

The digestion in sponges is intracellular. It takes place in coenocytic oral cells. The movement of water initiated by the coenocyteS. It helps in the digestion and respiratory system of sponges because along with the water they also transport oxygen. They then push out carbon dioxide which is a waste material out of the sponge body.

• Food is one of the basic requirements of all living organisms. 
  
• The major components of our food are carbohydrates, proteins and fats. Vitamins and minerals are also required in small quantities.  
• Biomacromolecules in food cannot be utilised by our body in their original form. They have to be broken down and converted into simple substances in the digestive system. 
• This process of conversion of complex food substances to simple absorbable forms is called digestion and is carried out by our digestive system by mechanical and biochemical methods. Hence, In a general sense, digestion is simply hydrolysis of complex polymers to monomers.

The digested food present in the food vacuole of amoeba is absorbed directly into the cytoplasm of amoeba cell by diffusion. Since, amoeba consists of only one small cell, it does not require blood system to carry the digested food. The digested food just spreads out from the food vacuole into the whole of amoeba cell. After absorption of food, the food vacuole disappears.

Grasshoppers have the typical insect body plan of head, thorax and abdomen.
 The thorax and abdomen are segmented and have a rigid cuticle made up of overlapping plates composed of chitin. Hence, Wall of a crop is muscular and its lumen is lined with cutile is wrong about the digestive system of a grasshopper.

Termites depend on protozoans which digest the cellulose ingested from the dead wood. Protozoa will die outside the termite and termite unable to digest the food without protozoans, hence they were in a symbiotic relationship.