Digestive System (Part-II)

Lipids are molecules that contain hydrocarbons and make up the building blocks of the structure and function of living cells. Examples of lipids include fats, oils, waxes, certain vitamins (such as A, D, E and K), hormones and most of the cell membrane that is not made up of protein.

Calorific value refers to the amount of heat liberated from the complete combustion of 1 g of food in a bomb calorimeter. The gross calorific value of fats is 9.45 kcal/g. For carbohydrates, it is 4.1 kcal/g and for proteins, it is 5.65 kcal/g.

Cholesterol is a type of lipid, just as fats are. However, unlike fat, cholesterol can’t be exercised off, sweated out or burned for energy. It is found only in animal products, including meat, chicken, fish, eggs, organ meats and high-fat dairy products.

Fermentation is another anaerobic (non oxygen-requiring) pathway for breaking down glucose, one that’s performed by many types of organisms and cells. In fermentation, the only energy extraction pathway is glycolysis, with one or two extra reactions tacked on at the end.

Stomach lining also secretes hydrochloric acid, which creates the ideal conditions for the protein-digesting enzymes to work. The potent hydrochloric acid kills bacteria, protecting your body from harmful microbes which can enter your body in food.

Bacterium Helicobacter pylori causes peptic ulcer. Barry J. Marshall and Robin Warren discovered H. Pylori in 1982 and received a Nobel prize for the same.

The mucus present in our stomach protects the stomach lining from the harmful effects of the hydrochloric acid.