Question

1. Metabolism. The body is able to readily burn glucose and lipids as fuel, but which source it uses depends on many factors.

   1. Identify the multiple chemical reactions that occur to create energy from carbohydrates (glucose).

   2. How does an excess of glucose cause an increase in the amount of fat present in the body? Be specific!

   3. What chemical reactions are required to turn triglycerides into energy?

Answer 1

Multiple chemical reaction that create energy from carbohydrates are

1. Glycolysis- it is the main pathway of glucose metabolism in which glucose passes through glycolysis and Kreb's cycle and yeild ATP.

2. Pentose phosphate pathway- this occur in liver . In this pathway, a hexose sugar is converted into pentose sugar and NADPH.

3. Fructose and galactose- these are another form of carbohydrates other than glucose. Fructose and galactose are converted into glucose in liver and then provide energy.

4. Glycogenesis : in this process, excess of glucose is converted into glycogen in liver and is stored.

5. Glycogenolysis: here glycogen is broken down into glucose.

6. Gluconeogenesis: here glucose is formed from the non-carbohydrate sources like laclate, glycerol ,alanine etc

2nd part of question-

excess of glucose when present in body is converted into glycogen in liver. With the help of insulin, this excessive amout is converted into fatty acids and gets stored in adipose tissues.

3rd part of question-

triglycerides gets converted into free fatty acids and glycerol by the process of lipolysis brought by lipase enzymes and bile. This formed fatty acid undergo beta-oxidation and gets converted into acetyl-coA. This acetyl-coA now enters kreb's cycle and liberates energy.

Glycerol directly enters the glycolysis process as DHAP( di hydroxy acetone phosphate) and thus release energy.