Question

(a) What product is released after the first step of glucose breakdown? Where does it take place?
(b) How are the small intestines designed to perform absorption of food?

Answer 1

(a)The glucose which is a 6 carbon molecule is broken down to two molecules of pyruvate in the first step of glucose oxidation (glycolysis). The glycolysis occurs in the cell cytoplasm. The pyruvate that is formed at the end of glycolysis is then transferred to mitochondria where complete oxidation of the pyruvate to carbon dioxide occurs.

(b) Almost all the nutrients present in the food after digestion are absorbed through the small intestine. The inner wall of the small intestine has many finger-like pieces of tissue called villi. These villi, in turn, have microvilli which are microfine finger-like projections. The purpose of microvilli is to increase the surface area required for nutrient absorption. These villi are also supplied with blood and lymphatic vessels to ensure rapid transfer of absorbed nutrients into circulation.