What is the difference between a primary oocyte and a secondary oocyte ?

1

(a)

A primary oocyte is diploid,while a secondary oocyte is haploid.

What is the significance of ampullaryisthmic junction in the female reproductive tract?

1

(a)

Ampullary-isthmic junction is the site in the fallopian tube where fertilisation occurs.

Name the part of gynoecium that determines the compatible nature of pollen grain.

1

(a)

Stigma

Mention two inhercent characteristics of Amoeba and yeast that enable them to reproduce asexually.

1

(a)

(i) Amoeba and yeast are single-called organisms.
(ii) They have a relatively simple organ-isation of cells.

What is the cross between the progeny of F₁ and the homozygous recessive parent called? How is it useful?

1

(a)

- It is called a test cross.

- It helps to determine the genotype of the F₁ individual with dominant phenotype.

Even if a character shows multiple allelism an individual will only have two allels for that character.  Why?

1

(a)

A diploid individual has only two sets of homologous chromosomes; hence only two alleles of a gene can be present on the homologous pair of chromosomes.

In some viruses DNA is synthesised using RNA template. What term is given to such a DNA?

1

(a)

Complementary DNA (cDNA)

What will be the ratio of  ¹⁵N/¹⁵N :¹⁵N/¹⁴N : ¹⁴N/¹⁴N containing DNAs,if Meselson and Stahl experiment is cotinued for four generations in the bacteria?

1

(a)

¹⁵N/¹⁵N O :¹⁵N/¹⁴N 2 : ¹⁴N/¹⁴N 14

How do we compute the age of a fossil?

1

(a)

The age of a fossil is calculated by radioactive (carbon) radiation.

If a patient is advised Anti-retroviral theraphy, which infection is he suffering from?Name the causative organism.

1

(a)

1. He is suffering from Acquired Immuno Deficiency Syndrome (AIDS).
2. Human Immunodeficiency virus (HIV).

Why are plants obtained by protoplast culture called somatic hybirds?

1

(a)

Since the plants is produced by the fusion of two different somatic cells, it is called a somatic hybird

Why are proteins synthesised from spirulina called single cell proteins?

1

(a)

The protein produced by microbes, is called single cell protein.

Bt cotton is resistant to pests, such as lepidopterans, dipterans and coleopterans. Is Bt cotton resistant to other pests as well?

1

(a)

What would be the growth curve pattern, when the resources are unlimited?

1

(a)

J - shaped growth curve.

In an association of two animal species, one is a termite which feeds on wood and the other is a protozoan Trichonympha present in the gut of the termite.  What type of association they establish?

1

(a)

Mutualism.

If a population of 50 Paramoecium present in a pool increases to 150 after an hour, what would be the growth rate of the population?

1

(a)

100 per hour.

How much of the net primary productivity of a terrestial ecosystem is eaten and digested by herbivores?

1

(a)

10 per cent.

What is common to earthworm,soil mites and dung beetles in an ecosystem?

1

(a)

They are all detritivores.

According to David Tilman, grater the diversity, greater is the primary productivity. Can you think of a very low diversity man-made ecosystem that has high productivity?

1

(a)

Agricultural or crop fields ( like wheat or rice field) have high productivity.

Why is genetic variation important in the plant Rauwolfia vomitoria?

1

(a)

Genetic variation is important as it affects the production of the drug reserpine in the medicinal plant Rawwolfia.

Would you choose an exonuclease for producing a recombinant DNA molecule?

1

(a)

No, because exonucleases will remove the nucleotides from the ends DNA molecule and not at any particular desired region.

In which year was the Air ( Prevention and Control of Pollution) Act amended to include noise as air pollutant?

1

(a)

1987

STDs can be considered as self-invited diseases.Comment.

1

(a)

Sexually Transmitted Diseases (STDs) can be considered self-invited diseases because these diseases develop due
to our own unsafe habits. But one could be free of these infections by following the simple principles given below
(i) Avoid sex with unknown partners/multiple partners.
(ii) Always use condoms during coitus.
(iii) In case of doubt one should go to a qualified doctor for early detection and get complete treatment if
diagnosed with disease.
If all the above said precautions are not strictly adopted by people, they are inviting STDsto infect them.

Strict conditions are to be followed in Medical Termination of Pregnancy (MTP) procedures.mention two reasons.

1

(a)

1. MTP is generally advised during first trimester of pregnancy as it becomes more and riskier as after this period fetus becomes more intimately associated with the uterine wall tissue.
2. Various methods of MTP require the help of qualified doctors.
3. To prevent illegal female foeticide.

Given below is the sequences of the coding strand of DNA in a transcription unit 3' AATGCAGCTATTAGG -5'. write the sequence of:
a) It's complementary strand
b)The mRNA.

1

(a)

a) 5'-TTACGTCGATAATCC-3'
B) 3'-AAUGCAGCUAUAGG-5'