Human Health and Disease — BIOLOGY STD 12 Science — Question

What are the functions of

1. Methylated guanosine cap and.
2. Poly-A tail in a mature mRNA?

Mention two important characteristics in the sexual reproduction of frogs and bony fishes.

Explain the significance of endosperm.

Write full form of ELISA. Give an example of the clinical application of ELISA test.

In the North East region of India, during the process of jhum cultivation, forests are cleared by burning and left for regrowth after a year of cultivation. How would you explain the regrowth of forest in ecological term?

A relevant portion of B-chain of haemoglobin of a normal human is given below:

The codon for the sixth amino acid is GAG. The sixth codon GAG mutates to GAA as a result of mutation 'A' and to GUG as a result of mutation 'B'. Haemoglobin structure did not change as a result of mutation 'A', whereas haemoglobin structure changed because of mutation 'B', leading to sickle-shaped RBCs. Explain giving reasons how could mutation 'B' change the haemoglobin structure or bring down mutation and not mutation 'A'.

pairs of contrasting characters of:

1. Position of flowers.
2. Colours of pod.
3. Shape of pod.
4. Colour of seed, that were selected in pea plant by Mendel.

In a sea shore, the benthic animals live in sandy, muddy and rocky substrata and accordingly developed the following adaptations. Find the suitable substratum against each adaptation.

1. Burrowing ______________________.
2. Building cubes ________________________.
3. Holdfasts/ peduncle _________________________.

An alien piece of DNA needs to be integrated to a specific sequence of host DNA for its cloning. Is it true? if yes, explain. If this DNA is not picked up by host cells. Can you suggest a reason for it?

Write a note on fossil evidence. State the method by which age of fossils is calculated.