Molecular Basis of Inheritance — BIOLOGY STD 12 Science — Question

Do you think that friends can influence one to take alcohol/ drugs? If yes, how may one protect himself/ herself from such an influence?

Ranjana and Shilpi had a hot argument whether or not life is still originating on the earth today. Their neighbour, Mr. Kamal Mishra, a retired professor, who happened to be listening to the girls, called them and explained the matter in detail.

1. As a student of biology, what is your answer to the above problem? And why?
2. Recall the experiment of Miller, which simulated the primitive atmosphere.

1. What were the products obtained in his experiment?
2. How was energy provided in the experiment?

3. What would have been the energy source for origin of life on the earth?
4. Indicate the values shown by Mr. Kamal Mishra?

Arrange the following in the decreasing order (most important first) of their importance, for the welfare of human society. Give reasons for your answer.

Bioreactors are the inclusion carriers in any biotechnology based production process. The ultimate success of any biotechnological technique depends on the efficiency of the bioreactor due to large scale production and economy.
In the context of the above passage, answer the following questions :
(i) For optimization of a bioreactor system, list possible operating instructions (rules). Make a list of any four.
(ii) "Optimal growth and metabolic activities of cells." Mention the stages of growth mentioned in.
(iii) Is the bioproduct formed in the bioreactor completely ready for immediate use as desired? Write the appropriate reasons also to support your answer.

Give an account of the methods used in sequencing the human genome.

A flower of brinjal plant following the process of sexual reproduction produces 360 viable seeds.
Answer the following questions giving reasons:
How many megaspore mother cells are involved?

1. Mention the contributions of the following scientists:

1. Maurice Wilkins and Rosalind Franklin.
2. Erwin Chargaff.

2. Draw a double-stranded dinucleotide chain with all the four nitrogen bases. Label the polarity and the components of the dinucleotide.

Give the term/ reason:
Why does zona pellucida layer block the entry of additional sperms?

Read the following and answer any four questions from (i) to (v) given below:

Transgenic animals can serve as factories that in some cases, may produce large amount of proteins more efficiently. Transgenic mice have been engineered to express human antibodies by introducing large segment of human DNA encoding human immunoglobulin genes. In transgenic large animals such as cow or sheep proteins of pharmaceutical value can be produced in large quantities in milk which is later purified. Transgenesis can be used to alter many phenotypic properties including growth rate, fat composition, milk production, hair texture, etc.

1. The production of transgenic animals includes

1. Identification and separation of desired gene.
2. Combining the desired gene with appropriate vector.
3. Introduction of vector in cells, tissues or embryos.
4. All of these.

2. In transgenic animals, i.e., cow and sheep proteins of pharmaceutical value are produced in large quantities in the

1. Blood.
2. Accumulated fat.
3. Mammary glands.
4. None of these.

3. Mouse is mostly preferred animal for studies on gene transfer because.

1.  Short oestrous cycle.
2. Long gestation period.
3. Short generation time.
4. Production of one or two offspring per pregnancy.

1. Both (A) and (C)
2. Both (A) and (B)
3. Only D
4. Both (C) and (D).

4. Transgenic genes alter many phenotypic properties including:

1. Growth rate.
2. Fat composition.
3. Milk production.
4. All of these.

5. Assertion: Transgenic mice have been engineered to express human antibodies.

Reason: Large segment of human DNA encoding human immunoglobulin have been transferred to mice.

1. Both assertion and reason are true and reason is the correct explanation of assertion.
2. Both assertion and reason are true but reason is not the correct explanation of assertion.
3. Assertion is true but reason is false.
4. Both assertion and reason are false.

Categorise the following plants into hydrophytes, halophytes, mesophytes and xerophytes. Give reasons for your answers.

1. Salvinia.
2. Opuntia.
3. Rhizophora.
4. Mangifera.