Reproductive Health — BIOLOGY STD 12 Science — Question

Following is the DNA sequence representing a part of the gene:
TAC CCC CAC GAG TTA TAT ATA CGG GGG CAT CAT ATG From it derive

1. The RNA transcript
2. The spliced mRNA (assuming that all codons containing a C represent the intron)
3. The number of amino acids it can code for

Three water samples namely river water, untreated sewage water and Secondary effluent discharged from Sewage treatment plant were subjected to BOD test. The samples were labelled in A, B and C; but the laboratory attendant did not note which was which. The BOD values of the three samples A, B and C were recorded as 20 mg/L, 8mg/L and 400mg/L, respectively. Which sample of the water is most polluted? Can you assign the correct label to each assuming the river water is relatively clean?

“Pollen grains in wheat are shed at 3-celled stage while in peas they are shed at 2-celled stage.” Explain. Where are germ pores present in a pollen grain?

Name the hormone that maintains the functions of male accessory ducts and glands.

What is triple fusion ? Where and how does it take place ?

Give the chromosomal constitution and the resulting sex in each of the following syndromes:
Turner’s syndrome.

Name the embryonic stage that gets implanted in the uterine wall of a human female.

What are the characteristic features of a true-breeding line?

When was earth formed? What was its conditions at that time?

Write a short article on the utility of bacteriophage as a vector.