Class 12th Biology 2017 Set2 Outside Delhi Board Paper Solution
Question 25
Explain Polygenic inheritance and Multiple allelism with the help of suitable examples.
Answer
Polygenic inheritance: It is the inheritance of a characteristic that is controlled by more than one gene. Polygenic inheritance can produce unexpected phenotypes.Phenotypes that don't fit with Mendel's expected outcomes based on independent assoectment of dominant and recessive alleles.
Two examples of Polygenic inheritance are:
1 Skin colour in humans
2. Height in humans
Multiple allelism: In this more than one alleles governs the same character and phenotype.
Example: Human blood group (ABO system) controlled by three alleles (IA, IB and i)
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:- What is oogenesis? Give a brief account of oogenesis.
- Q:- Describe the structure of a seminiferous tubule.
- 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:- Define spermiogenesis and spermiation.
- Q:- What are Cry proteins? Name an organism that produces it. How has man exploited this protein to his benefit?
- Q:- Do you think that reproductive health in our country has improved in the past 50 years? If yes, mention some such areas of improvement.
- Q:- Crystals of Bt toxin produced by some bacteria do not kill the bacteria themselves because −
(a) bacteria are resistant to the toxin
(b) toxin is immature:
(c) toxin is inactive:
(d) bacteria encloses toxin in a special sac. - Q:- What is spermatogenesis? Briefly describe the process of spermatogenesis.
- Q:- Describe the structure of a seminiferous tubule.
- Q:- From what you have learnt, can you tell whether enzymes are bigger or DNA is bigger in molecular size? How did you know?
- Q:- Find out from internet what is golden rice.
- Q:- Explain (in one or two lines) the function of the followings:
(a) Promoter
(b) tRNA
(c) Exons - Q:- Discuss briefly the following:
(a) Radioactive wastes
(b) Defunct ships and e-wastes
(c) Municipal solid wastes