Biology Delhi Set 3 2016-2017 Commerce (English Medium) Class 12 Question Paper Solution

What is biopiracy?

Suggest a method to ensure an anamnestic response in humans.

State the fate of a pair of autosomes during gamete formation.

Our government has intentionally imposed strict conditions for M.T.P. in our country. Justify giving a reason.

Rearrange the human activities mentioned below as per the order in which they developed after the modern Homo sapiens came into existence during ice age:

(i) Human settlement
(ii) Prehistoric cave art
(iii) Agriculture

Plenty of algal bloom is observed in a pond in your locality.

(a) Write what has caused this bloom and how does it affect the quality of water.
(b) Suggest a preventive measure.

How do mycorrhizae help the plants to grow better?  

Mention the ploidy of the different types of cells present in the female gametophyte of an angiosperm.

Describe the structure of a nucleosome.

Mention the evolutionary significance of the Shrews

Mention the evolutionary significance of the Lobefins

Mention the evolutionary significance of the Homo habilis

"Growing Spirulina on a large scale is beneficial both environmentally and nutritionally for humans," Justify.

A number of passengers were severely burnt beyond recognition during a train accident. Name and describe a modern technique that can help hand over the dead to their relatives.

What is inbreeding depression?

Explain the importance of "selection" during inbreeding in cattle

p² + 2pq + q² = 1. Explain this algebraic equation on the basis of Hardy Weinberg's principle.

During a medical investigation, an infant was found to possess an extra  chromosome-21. Describe the symptoms the child is likely to develop later in the life.

Describe the structure of a seminiferous tubule.

Parthenocarpy and apomixis have been observed in some plants. Give an example of each.

State a similarity and a difference observed between Parthenocarpy and apomixis.

Describe how do 'flocs' and 'activated sludge' help in Sewage Treatment.

Explain the role of Restriction endonuclease in Biotechnology

Explain the role of the Gel − electrophoresis in Biotechnology

Explain the role of the Selectable markers in pBR322 in Biotechnology.

Why do lepidopterans die when they feed on Bt cotton plant? Explain how does it happen.

Show with the help of a flow chart only, the life cycle of malarial parasite in humans.

'in-situ' Conservation can help endangered/threatened species. Justify the statement.

Name and describe any three causes of bio-diversity losses.

Write the steps you would suggest to be undertaken to obtain a foreign-gene-product.

Public all over India is very much concerned about the deteriorating air quality in large parts of North India. Alarmed by this situation the Resident's Welfare Association of your locality organized an awareness programme entitled "Bury not burn". They invited you, being a biology student to participate.

(a) How would you justify your arguments that promote burying and discourage burning? (Give two reasons)

(b) With the help of flow charts, one for each practice depict the chain of events that follow.

Work out a typical Mendelian dihybrid cross and state the law that he derived from it.

How do the observations made during moth collection in pre- and post- industrialized era in England support evolution by Natural Selection?

Explain the phenomenon that is well represented by Darwin's finches other than natural selection.

What is an age-pyramid?

Represent diagrammatically three kinds of age-pyramids for human populations.

Discuss the role of healthy ecosystem services as a pre-requisite for a wide range of economic, environmental and aesthetic goods and services

A capsicum flower has 240 ovules in its ovary. But, it produces a fruit with only 180 viable seeds.
 

Describe the development of an endosperm in a viable seed. Why does endosperm development precedes embryo development?

Give an example of an angiosperm seed that has a perisperm. Name the part the perisperm develops from.

Where in the fallopian tube does fertilization occur in humans?

Describe the development of a fertilized ovum upto implantation.

How is polyspermy prevented in humans?