Question

Name the process that helps in the transfer of food substances in the body of multicellular organisms.

Answer 1

Food is one of the basic requirements of all living organisms, major components of our food are carbohydrates, proteins, and fats. Vitamins and minerals are also required in small quantities. The water we take in plays an important role in metabolic processes and prevents dehydration of the body.

Complete answer:
Bio-macromolecules (proteins, nucleic acids, polysaccharides, and lipids) cannot be utilized directly in their original form into the body of multicellular organisms.
These molecules have to be broken down into simple substances in the digestive system, this process of conversion of complex food substances into simple absorbable forms is called digestion and is carried out by our digestive system by mechanical and biochemical methods.
The human digestive system consists of the alimentary canal and the associated glands ( these glands help in the digestion of food).
The alimentary canal consists of the mouth, buccal cavity, pharyngitis, esophagus, stomach, small intestine, large intestine, rectum, and anus.
The accessory digestive glands include salivary glands, the liver(with gallbladder), and the pancreas.
Inside the mouth, the teeth masticate the food , the tongue tastes the food and helps in proper mastication by mixing with the saliva.
Saliva contains a starch digestive enzyme, salivary amylase that digests the starch and converts it into Maltose ( disaccharide).
The food then passes into the pharyngitis and enters the esophagus in the form of a bolus, which is further carried down 5hrough the esophagus by peristaltic into the stomach.
In the stomach mainly protein digestion takes place and absorption of simple sugars, alcohol and certain drugs also takes place in the stomach.
The chyme(mass of food) enters into the duodenum portion of the small intestine and is acted on by the pancreatic juice, bile, and finally by the enzymes in the succus enteric, so that the digestion of carbohydrates, proteins, and fats is completed.
The food then enters into the jejunum and ileum portion of the small intestine.
Carbohydrates are digested and converted into monosaccharides like glucose. Proteins are finally broken into amino acids. The fats are converted to fatty acids and glycerol.
The digested end products are absorbed into the body through the epithelial lining of the intestinal villa.
The undigested food (feces) enters into the calcium of the large intestine through the ileocaecal valve which prevents the backlog of the fecal matter.
Most of the water is absorbed in the large intestine.
The undigested food becomes semi-solid in nature and then enters into the rectum, anal canal and is finally elected out through the anus.

Note:
Different multicellular organisms have different digestive systems eg: simple multicellular organisms like a hydra, Flatworm has one opening digestive system, whereas more complex organisms have two openings one for ingestion and the other for excretion.The stomach of ruminants is the compound stomach, it has 4 well-defined chambers ie rumen, reticulum, omasum, and abdomen.