Question

metabolism what role does it play in our body

Answer 1

INTRODUCTION

Our body needs energy to do all actions.Carbohydrates, proteins, lipids are considered as the fuel for our body.These are undergo certain chemical reactions and converted into energy through metabolism. Endocrine glands helps to control the rate of metabolism.The main galnds involved in the metabolism are thyroid gland and pancreas.

DEFINITION OF METABOLISM

It is a chemical process in which our body converts the food and drinks into energy. Metabolism is closely related to availability of nutrients in the body.

PURPOSE OF METABOLISM IN OUR BODY

1.Conversion of food into energy

BMR- It is the minimum calorie requirement of the body while the body rests. It is essential to maintain the vital functioning of heart, brain, lungs

Factors affecting BMR

Age

Sex

Body size

Physical exercise

Food processing

2. Elimination of waste products-The metabolic waste products are carbon dioxide, water, salt, urea and uric acid.The elimination of waste products from body is called excretion

TYPES OF METABOLISM

a. Catabolism - It is the breaking down of compounds (glucose to pyruvate) to obtain energy

b. Anabolism-It is the synthesis of all compounds like carbohydrates, proteins, lipids, nucleic acids etc

METABOLIC PATHWAYS

1. Glycolysis- Here glucose oxidation occurs and ATP (Adenosine triphosphate) is obtained. In the first half glucose is converted into glucose 6 phosphate, fructose 6 phosphate, glyceraldehyde 3 phosphate and fructose 1, 6 diphosphate.In this part phosphorylation occurs with two ATP molecules. In the second half produces 2 NADH (Nicotinamide adenine dinucleotide with hydrogen) and 4 ATP molecules with out any involvement of phosphorylation

2. Citric acid cycle/Kreb's cycle - Here acetyl co enzyme A oxidation occurs and GTP (Gunosine Tri Phosphate) is obtained.In this step pyruvate is converted into citrate, iso citrate, alpha keto glutarate, succinate, fumarate , malate and oxaloacetate.

3. Pentose phosphate pathway-Also called phospho gluconate pathway and hexose monophosphate shunt.Here the synthesis of pentones occurs.The main products are ribose 5 phosphate and NADPH.

4. Urea cycle- Catabolism of amino acids forms ammonia.Here highly toxic ammonia is converted to less toxic form of urea (NH4+ form)

5.Fatty acid beta oxidation-During fatty acid oxidation,fatty acida are broken down into acetyl Co Enzyme which can enter into Kreb's cycle and can be used for energy.

6. Gluconeogenesis-Synthesis of glucose from non carbohydrate substrates like lactate, pyruvate etc. It mainly takes place in liver and can happen in kidney and small intestine .