Lesson Archives

  1. Page No 205: Question 1: Can you list 10 recombinant proteins which are used in medical practice? Find out where they are used as therapeutics (use the internet). Answer: Recombinant proteins are obtained from the recombinant DNA technology. This technology involves the transfer of specific genes from an organism into another organism using vectors and […]
  2. Page No 189: Question 1: Bacteria cannot be seen with the naked eyes, but these can be seen with the help of a microscope. If you have to carry a sample from your home to your biology laboratory to demonstrate the presence of microbes under a microscope, which sample would you carry and why? Answer: […]
  3. Page No 178: Question 1: Explain in brief the role of animal husbandry in human welfare. Answer: Animal husbandry deals with the scientific management of livestock. It includes various aspects such as feeding, breeding, and control diseases to raise the population of animal livestock. Animal husbandry usually includes animals such as cattle, pig, sheep, poultry, […]
  4. Page No 164: Question 1: What are the various public health measures, which you would suggest as safeguard against infectious diseases? Answer: Public health measures are preventive measures which are taken to check the spread of various infectious diseases. These measures should be taken to reduce the contact with infectious agents. Some of these methods […]
  5. Page No 142: Question 1: Explain antibiotic resistance observed in bacteria in light of Darwinian selection theory. Answer: Darwinian selection theory states that individuals with favourable variations are better adapted than individuals with less favourable variation. It means that nature selects the individuals with useful variation as these individuals are better evolved to survive in […]
  6. Page No 125: Question 1: Group the following as nitrogenous bases and nucleosides: Adenine, Cytidine, Thymine, Guanosine, Uracil and Cytosine. Answer: Nitrogenous bases present in the list are adenine, thymine, uracil, and cytosine. Nucleosides present in the list are cytidine and guanosine. Question 2: If a double stranded DNA has 20 per cent of cytosine, […]
  7. Page No 93: Question 1: Mention the advantages of selecting pea plant for experiment by Mendel. Answer: Mendel selected pea plants to carry out his study on the inheritance of characters from parents to offspring. He selected a pea plant because of the following features. (a) Peas have many visible contrasting characters such as tall/dwarf plants, […]
  8. Page No 66: Question 1: What do you think is the significance of reproductive health in a society? Answer: Reproductive health is the total well being in all aspects of reproduction. It includes physical, emotional, behavioural, and social well being. Sexually transmitted diseases such as AIDS, gonorrhoea, etc. are transferred from one individual to another […]
  9. Page No 55: Question 1: Fill in the blanks: (a) Humans reproduce __________. (asexually/sexually) (b) Humans are__________. (oviparous/viviparous/ovoviviparous) (c) Fertilization is __________ in humans. (external/internal) (d) Male and female gametes are __________. (diploid/haploid) (e) Zygote is __________. (diploid/haploid) (f) The process of release of the ovum from a mature follicle is called__________. (g) Ovulation is induced by a hormone called the __________. […]
  10. Page No 40: Question 1: Name the parts of an angiosperm flower in which development of male and female gametophyte take place. Answer: The male gametophyte or the pollen grain develops inside the pollen chamber of the anther, whereas the female gametophyte (also known as the embryo sac) develops inside the nucellus of the ovule […]