Question

Why do we get instant energy from glucose?

Answer 1

Hint: The food we eat is broken down in simpler carbohydrate molecules by the oxidation. This oxidation releases a certain amount of energy which helps the organism to carry out work. The food is stored in our body in the form of glucose.

Complete Answer:
- Glucose is a monosaccharide whose chemical formula is $C_{6}H_{12}O_6$. We take in food to get energy. The food is composed of complex carbohydrates, proteins, fats. These are broken down into simpler carbohydrates by the enzyme present in the digestive system. These carbohydrates are the instant source of energy.
- Oxidation of glucose- The glucose is oxidised aerobically by respiration. One molecule of glucose on complete oxidation yields 2870 KJ of energy which is instantly utilised by the body.

Glucose + Oxygen $\to$ Carbon dioxide + Water + Energy

- Whereas, when lipids, other carbohydrates and proteins are oxidised, they produce intermediates which are further oxidised to glucose. This is a time taking process.

So glucose is considered as an immediate energy source.

Additional Information: The oxidation of glucose takes place by the process called cellular respiration. The process takes place in two steps: Glycolysis which takes place in cytoplasm and kreb cycle which takes place in mitochondria. This results in ATP which is known as the energy currency of the cell.

Note: Our body needs energy for daily activities. We get energy from the food we eat. The food is broken down into simple monomers of carbohydrates like glucose and liberates energy. For example the disaccharides and oligosaccharides are also broken down to simpler monosaccharide.