CBSE Class 12 Biology Compartment Question Paper 2026 with Solution PDF

Name the phenomenon that leads to situations like ‘XO’ abnormality in humans. Also name this genetic disorder. How are individuals with an XO chromosomal abnormality affected? Write its symptoms as well as karyotype.

Read the following passage and answer the questions that follow:
India is one of the megadiverse countries housing around 8·1 per cent of global species diversity, although its land area is only 2·4 per cent of the world’s land area. Many of the species are highly threatened due to human activities like deforestation, mining and habitat fragmentation. Laws like Wildlife (Protection) Act, 1972 were enacted by the Government of India to preserve our biological wealth. Various conservation measures are being implemented to save the threatened species. The following bar graph shows the number of species conserved under different biodiversity conservation methods.

Which other methods shown in the diagram are opposite to the one identified by you in question ? How are these two conservation approaches different?
(c) Write two features of Biodiversity hotspots.
(c) To which category do sacred groves belong and how do they help in bio-conservation?

Draw a neat diagram of a maize grain showing the internal structure and label any five parts.

Cow dung and water are mixed and fed into a biogas plant to allow digestion of biowastes. The person performing this process says that there is no need to provide an inoculum.
Do you agree with him? Justify your answer.
What happens to the biowaste inside the digester ?
(c) Name the useful by-products obtained from this process and mention how they are used.

Draw a labelled two-celled structure of male gametophyte of an angiosperm.
Name the three layers that surround the cytoplasm of a male gametophyte starting from innermost to outermost layer.
(iii) Which organic material makes the outermost layer? Mention its advantage.
(iv) Why is the outermost layer of male gametophyte not continuous ?

In vitro fertilization (IVF) is a popular method these days that is helping childless couples to bear a child.
Write the different steps that are carried out in this technique.
Would you consider gamete intra fallopian transfer as a type of IVF? Justify your answer.

Explain any two basic principles/core techniques on which biotechnology is based.
Describe any three key tools used in Recombinant DNA technology.

What is the carrying capacity of a species in a habitat?
Explain the growth curve that takes this capacity into account.

Describe the series of experiments conducted by Frederick Griffith. Comment on the significance of the result obtained.
State the contribution of Avery, MacLeod and McCarty.

Describe the experiment conducted by T.H. Morgan on Drosophila melanogaster involving eye colour and body colour.
How did the results deviate from Mendelian inheritance pattern ?
(c) Explain the two genetic terms used by Morgan for his observations.

What is meant by translation in protein synthesis?
Explain charging of tRNA (aminoacylation of tRNA) and mention its importance in the process of translation.

Work out the crosses between:
Normal female and Haemophilic male
Carrier female and Normal male
(III) Carrier female and Haemophilic male
Write the conclusions you draw from these crosses. Comment on the type of inheritance of the disease.
(Use: $X$ - Normal, $X^h$ - Haemophilic)

Oogenesis is a discontinuous process that begins before birth and is completed after puberty.
Trace the development of a gamete mother cell till its release from the ovary during ovulation.
Name the two pituitary hormones that play an important role in the process.

"Early and accurate diagnosis of diseases is vital in medical technology."
Name the conventional methods of diagnosis and their disadvantages.
Which three diagnostic techniques have been developed through Biotechnology ? Explain how each one helps in detecting diseases.