Lesson Archives

  1. Page No 328: Question 1: Briefly describe the structure of the following: Brain (b) Eye (c) Ear Answer: (A) Brain: Brain is the main coordinating centre of the body. It is a part of nervous system that controls and monitors every organ of the body. It is well protected by cranial meninges that are made […]
  2. Page No 313: Question 1: Draw the diagram of a sarcomere of skeletal muscle showing different regions. Answer: The diagrammatic representation of a sarcomere is as follows: Question 2: Define sliding filament theory of muscle contraction. Answer: The sliding filament theory explains the process of muscle contraction during which the thin filaments slide over the […]
  3. Page No 300: Question 1: Define Glomerular Filtration Rate (GFR) Answer: Glomerular filtration rate is the amount of glomerular filtrate formed in all the nephrons of both the kidneys per minute. In a healthy individual, it is about 125 mL/minute. Glomerular filtrate contains glucose, amino acids, sodium, potassium, urea, uric acid, ketone bodies, and large […]
  4. Page No 289: Question 1: Name the components of the formed elements in the blood and mention one major function of each of them. Answer: The component elements in the blood are: (1) Erythrocytes: They are the most abundant cells and contain the red pigment called haemoglobin. They carry oxygen to all parts of the […]
  5. Page No 277: Question 1: Define vital capacity. What is its significance? Answer: Vital capacity is the maximum volume of air that can be exhaled after a maximum inspiration. It is about 3.5 – 4.5 litres in the human body. It promotes the act of supplying fresh air and getting rid of foul air, thereby […]
  6. Page No 267: Question 1: Choose the correct answer among the following: (a) Gastric juice contains (i) pepsin, lipase and rennin (ii) trypsin lipase and rennin (iii) trypsin, pepsin and lipase (iv) trypsin, pepsin and renin (b) Succus entericus is the name given to (i) a junction between ileum and large intestine (ii) intestinal juice […]
  7. Page No 253: Question 1: Define growth, differentiation, development, dedifferentiation, redifferentiation, determinate growth, meristem and growth rate. Answer: (a) Growth It is an irreversible and permanent process, accomplished by an increase in the size of an organ or organ parts or even of an individual cell. (b) Differentiation It is a process in which the […]
  8. Page No 238: Question 1: Differentiate between (a) Respiration and Combustion (b) Glycolysis and Krebs’ cycle (c) Aerobic respiration and Fermentation Answer: (a) Respiration and combustion Respiration Combustion 1. It is a biochemical process. 1. It is a physiochemical process. 2. It occurs in the living cells. 2. It does not occur in the living cells. […]
  9. Page No 224: Question 1: By looking at a plant externally can you tell whether a plant is C3 or C4? Why and how? Answer: One cannot distinguish whether a plant is C3 or C4 by observing its leaves and other morphological features externally. Unlike C3 plants, the leaves of C4 plants have a special anatomy called Kranz anatomy and […]
  10. Page No 205: Question 1: ‘All elements that are present in a plant need not be essential to its survival’. Comment. Answer: Plants tend to absorb different kinds of nutrients from soil. However, a nutrient is inessential for a plant if it is not involved in the plant’s physiology and metabolism. For example, plants growing […]