NCERT Class 12 Biology Solutions: Chapter 13 – Organisms and Populations

How is diapause different from hibernation?

Solution: Diapause is defined as the stage of suspended development in order to cope with unfavourable conditions. Many species of zooplankton and insects show diapause to survive adverse climatic conditions during their development. 

Hibernation or winter sleep is a resting stage shown by animals to escape winters by hiding themselves in their shelters.

Read More

NCERT Class 12 Biology Solutions: Chapter 11 – Biotechnology: Principles and Processes

Can you list 10 recombinant proteins which are used in medical practice? Find out where they are used as therapeutics (use the internet).


Recombinant proteins Therapeutic use
DNAse Mucoviscidosis
Interleukin Cancer
Human growth hormone Dwarfism
Glucocerebrosidase Gaucher’s disease
Human insulin Diabetes
Tissue plasminogen activator Myocardial infarction
Insulin-like growth factor Childhood growth anabolic effects in adults
Erythropoietin Stimulation of production of erythrocytes
Interferon Treatment of infectious diseases like multiple sclerosis
Alpha-galactosidase A Enzyme replacement therapy


Make a chart (with diagrammatic representation) showing a restriction enzyme, the substrate DNA on which it acts, the site at which it cuts DNA and the product it produces.

Read More

NCERT Class 12 Biology Solutions: Chapter 9 – Strategies for Enhancement in Food Production

Explain in brief the role of animal husbandry in human welfare.

Solution: Animal husbandry deals with the scientific management of livestock. The aspects it includes are feeding, breeding and control diseases to raise the population of animal livestock. It usually includes animals such as cattle, pig, sheep, etc., which are useful for humans in various ways.

Read More

NCERT Class 12 Biology Solutions: Chapter 8 – Human Health and Disease

What are the various public health measures, which you would suggest as safeguard against infectious diseases?

Solution: Public health measures are preventive measures which are taken to check the spread of various infectious diseases.

Some of these methods are

  • Maintenance of personal and public hygiene: This measure includes maintaining a clean body, consumption of healthy and nutritious food, drinking clean water, etc.
Read More

NCERT Class 12 Biology Solutions: Chapter 6 – Molecular Basis of Inheritance

Group the following as nitrogenous bases and nucleosides

Adenine, Cytidine, Thymine, Guanosine, Uracil, and Cytosine.

Solution: Nitrogenous bases present in the list are adenine, thymine, uracil, and cytosine.  Nucleosides present in the list are cytidine and guanosine.

If a double-stranded DNA has 20 percent of cytosine, calculate the percent of adenine in the DNA.

Read More

NCERT Class 12 Biology Solutions: Chapter 5 – Principles of Inheritance and Variation

Mention the advantages of selecting a pea plant for the experiment by Mendel.

Solution: Mendel selected pea plants to carry out his study on the inheritance of characters from parents to offspring.  He selected a pea plant for the following features:

  • Pea plant has many visible contrasting characters such as tall/dwarf plants, purple/white flowers, etc.
Read More