Class 12th Biology 2014 Set3 Delhi Board Paper Solution
A colour-blind child is born to a normal couple. Work out a cross to show how it is possible. Mention the sex of this child.
OR
Mendel published his work on inheritance of characters in 1865, but it remained unrecognised till 1900. Give three reasons for the delay in accepting his work.
Colour blindness is a sex-linked disease. The gene for this disorder is present on the X chromosome. Hence, it is carried by normal females not expressing the disease. If a colour-blind child is born to a normal couple, then the mother would be the carrier of the disease. The child would be male. The following cross shows the inheritance of the disorder
OR
The following are the three reasons that led to the delay in accepting Mendel's work:
1) Lack of communication and publicity.
2) His concept of factors (genes) as discrete units that did not blend with each other was not accepted in the light of variations occurring continuously in nature.
3) Mendel approach to explain biological phenomenon with the help of mathematics was also not accepted.
Popular Questions of Class 12th biology
- Q:- What is spermatogenesis? Briefly describe the process of spermatogenesis.
- Q:- Why is reproduction essential for organisms? Answer
- Q:- Write a short note on
(a) Adaptations of desert plants and animals
(b) Adaptations of plants to water scarcity
(c) Behavioural adaptations in animals
(d) Importance of light to plants
(e) Effect of temperature or water scarcity and the adaptations of animals. - Q:- With a neat diagram explain the 7-celled, 8-nucleate nature of the female gametophyte.
- Q:- What is DNA fingerprinting? Mention its application.
- Q:- Describe the structure of a seminiferous tubule.
- Q:- What is oogenesis? Give a brief account of oogenesis.
- Q:- What is triple fusion? Where and how does it take place? Name the nuclei involved in triple fusion.
- Q:- With a neat, labelled diagram, describe the parts of a typical angiosperm ovule.
- Q:- Explain the Law of Dominance using a monohybrid cross.
Recently Viewed Questions of Class 12th biology
- Q:- Write a short note on
(a) Adaptations of desert plants and animals
(b) Adaptations of plants to water scarcity
(c) Behavioural adaptations in animals
(d) Importance of light to plants
(e) Effect of temperature or water scarcity and the adaptations of animals. - Q:- Is sex education necessary in schools? Why?
- Q:- The species diversity of plants (22 per cent) is much less than that of animals (72 per cent). What could be the explanations to how animals achieved greater diversification?
- Q:- What are sacred groves? What is their role in conservation?
- Q:- How is biodiversity important for ecosystem functioning?
- Q:- Can you think of a situation where we deliberately want to make a species extinct? How would you justify it?
- Q:- What is the significance of the slope of regression in a species − area relationship?
- Q:- What is DNA fingerprinting? Mention its application.
- Q:- Define decomposition and describe the processes and products of decomposition.
- Q:- Differentiate between gametogenesis from embryogenesis.