Question 2.
Write definitions.
a. Nutrition.
b. Nutrients
c. Proteins.
d. Cellular respiration
e. Aerobic respiration.
f. Glycolysis.
Answer:
a. Nutrition: Food is needed by all living organisms for growth and repair. Variety of substances are taken as food from single cellular organisms like Amoeba to the complex multicellular organisms like the human body. The method of taking food by organism is called nutrition.
b. Nutrients: A nutrient is a substance which is used by an organism to survive, grow, and reproduction. Living organisms obtained nutrients from the food. Carbohydrates, fats, proteins, vitamins, minerals, etc., are the nutrients obtained from food.
c. Proteins: Proteins are the large complex molecules formed by bonding together many amino acids by peptide bonds. Examples, hair, nail muscles are proteins.
d. Cellular respiration: Cellular respiration is the process by which cells get their energy in the form of ATP from oxidation of food. Cellular respiration takes place in presence or in absence of oxygen.
e. Aerobic respiration: It is the process of producing cellular energy by the oxidation of food such as glucose in the presence of oxygen. It is a multistep process that produces 38 ATP.
C6H12O6 + 6O2 --> 6CO2 + 6H2O + 38 ATP (net gain 36 ATP)
Glucose + oxygen --> carbon dioxide + water + energy
f. Glycolysis: Glycolysis is the first step in cellular respiration. It takes place in the cytoplasm of a cell. In this process 1 molecule of glucose is converted into 2 molecules of pyruvic acid or pyruvate.
