20 **Question 20**Which of the following is (are) true for the “feeder pathways” for glycolysis?(i) Galactose is converted to glucose-1-phosphate prior to its entry into the pathway (ii) In mammalian liver, fructokinase converts fructose to fructose-6-phosphate (iii) A trios-kinase converts glyceraldehyde to glyceraldehyde-3-phosphate - O ii and iii- O i, ii, and iii- O iii only- O i and ii- O i and iii**Question 21**Glycogen de-branching enzymes carry out all of the following except:- O hydrolyzing the alpha (1→4) bond- O exhibiting specificity for the (1→6) glucosidase activity- O releasing glucose as free glucose(Note: No graphs or diagrams are present in the image.)

All the chemical reactions that occur inside the body and sustain the life processes are together summed up as the metabolism. There are various metabolic pathways that occur inside the body like glycolysis, glycogenesis, citric acid cycle, beta-oxidation, and so on. The metabolic pathway that takes place in the cytoplasmic region of cells and results in the cleavage of glucose into two molecules with three carbons each and the generation of energy is termed glycolysis.Carbohydrates like fructose, galactose also enter the pathway of glycolysis by the action of a few specific enzymes. These molecules enter this pathway at different stages. In liver cells the enzyme fructokinase aids in converting fructose to fructose-1-phosphate which enters the pathway. The galactose molecule is first converted to galactose-1-phosphate and it is changed to glucose-1-phosphate where uridine phosphate acts as a carrier. Once fructose-1-phosphate enters the pathway it is changed to glyceraldehyde with the help of enzyme triose kinase. Since the only incorrect statement is (ii). Hence, the correct option is (ii) and (iii).