Tag: digestion and absorption

• Most of the fat in the human diet is in the form of triacylglycerol, which consists of three fatty acids linked to glycerol.
• In the digestive tract,  triacylglycerol is hydrolyzed by the enzyme pancreatic lipase, to release free fatty acids and monoglycerides. Hence, If you have just digested triglyceride molecules, you would expect to find increased amounts of fatty acids and glycerol.

• Most lipids that you consume in your diet are fats. Some digestion occurs in your mouth and the stomach but mostly takes place in the small intestine. The purpose of the small intestine is to finish digestion and absorb nutrients. The small intestine is where most chemical digestion takes place. 
• Many of the digestive enzymes that act in the small intestine are secreted by the pancreas and liver and enter the small intestine via the pancreatic duct. Hence, most of the digestion of lipids in humans takes place in the small intestine.
  

• Trypsin is produced in the pancreas as an inactive protease trypsinogen. It is a protease found in the digestive system of many vertebrates, where it hydrolyses protein.

CCK is in the duodenum and stimulates the release of digestive enzymes in the pancreas and stimulates the emptying of bile in the gallbladder. This hormone is secreted in response to the fat in the chyme

In the intestinal mucosal cells, after absorption, the triglycerides and cholesterol are re-esterified to form chylomicrons. The chylomicrons in turn are secreted into intestinal lymph, enter the blood stream through the thoracic duct and bind to the wall of capillaries in adipose and skeletal tissue.

• Digestion is the process where complex material in the food is broken down to simple nutrients and molecules so that they can be absorbed and circulated in the body. 
• The digestion of the food starts in the buccal cavity of the organism where the enzyme amylase is secreted. This enzyme is used for the digestion of the starch present in the food. Though much of the starch is digested in the mouth it is divided in disaccharide units of carbohydrates which will be further digested in intestine. 
• The food from the buccal cavity is taken to the stomach via oesophagus where the food is stored for about 3 to 4 hours and mixed with the hydrochloric acid which is secreted by the oxyntic cell present in the mucosa wall of the stomach. This will give the food a acidic pH which is necessary for the activation of the pepsin enzyme which are there for digestion of proteins to peptides. 
• This acidic chyme of the stomach is to be transported for further digestion in the intestine where it is mixed with the alkaline secretion released from the liver and pancreas. 
• In intestine the food components such as carbohydrates, proteins, lipids etc are digested to small absorbable molecules. 
• The carbohydrates are digested to monosaccharides glucose, fructose, galactose, proteins are broken down to amino acids and lipids are reduced to small fat globules called microns. 
• Some of these components are already present in the cell fo the body surrounding the digestive track. So for the transport of molecules ion transporters are used sach as sodium ion transporter, etc. 
• Glucose is easily digested compared to other molecules of monosaccharides as it is easily soluble in water. Monosaccharides such as fructose and amino acid units are transported to the blood stream along with the sodium ions that are transportedby the sodium ion transporter. 
• Fat globules are transported by the lacteal cells that are present in the intestine mucosa of the intestine. Chylomicrons are also used to transport fat to liver and adipose tissue where it can be stored. 
• Therfore for the following question option A and C are correct. 

(A) Lipase - Fats

Rennin is an aspartic endopeptidase belonging to MEROPS A1 family. It is produced by newborn ruminant animals in the lining of the abomasum to curdle the milk they ingest, allowing a longer residence in the bowels and better absorption. It is widely used in the production of cheese. Lactase is an enzyme produced by many organisms.  Lactase can be purchased as a food supplement, and is added to milk to produce "lactose-free" milk products. Lactase is the enzymes that splits lactose (milk sugar) into glucose and galactose. The enzymes necessary to break down and digest milk (rennin and lactase) are all gone by the age of three in most humans. 

The correct answer is (c).