Question

2. How many reducing ends are in the molecule of glycogen which contains 5,000 residues with branch every 10 residues?

3. Imagine a person that has a genetic defect in the ability of liver to store large amounts of glycogen. In which cases would that person be limited by this physiological defect and can you think of ways to mitigate such limitations.

4. Disaccharides can be linked together in many ways depending on what anomer is used and what carbons are linked together. For the disaccharides trehalose, sucrose and lactose draw (do not copy and paste) the disaccharide and indicate the type of glycosidic bond that is present (i.e., in chitin, two glucose molecules are bonded together via b 1-4 linkages). Furthermore please be sure to label the individual monosaccharides.

1. 4a. Trehalose
2. 4b. Lactose
3. 4c. Sucrose

5. Explain how chemical coupling of endergonic and exergonic reactions is used to generate ATP during glycolysis.

Answer 1

2. Each glycogen chain only consist of one reducing end . So the straight chain of glycogen has only 1 reducing end.

Given the glycogen branches in every 10 residues. So there are total 500 branching residues. Each branch has one reducing end. So the reducing end from branches along constitute 500. So total there are 501 reducing ends.

3. Glycogen is the glucose reserve of the body. Defective glycogen storage due to defect in enzymes such as Glycogen synthase, glycogen kinase etc can therfore lead reduced glucose reserve in the body. There will be frequent muscle cramps due to reduced glucose content. These individuals have increased predisposition to severe hypoglycemia. The hypoglycemia may sometimes cause serious and fatal central nervous manifestations. The condition can be treated with supplying small quantities of carbohydrates at short intervals.

4.

5. Exergonic reactions are those reactions that release energy as they proceed whereas endergonic reactions absorbs energy for proceeding. In biological system endergonic reactions are coupled with exergonic reactions so that the energy released from latter is useful in proceeding of the former.

In glycolysis formation of ATP is an endergonic process. So it is carried out by coupling with those steps of glycolysis that are exergonic. In glycolytic pathway energy release occurs in two steps.

a) Conversion of 1,3-biphosphoglycerate to 3-phosphoglycerate.

b) Conversion of phosphoenol pyruvate to pyruvate.

The both steps are depicted below.