Reproduction in Lower and Higher Animals — BIOLOGY STD 12 Science — Question

DNA in prokaryotic and eukaryotic cells.

What do you think is the significance of reproductive health in a society?

Given below is an enlarged view of onemicro sporangium of a mature anther.

1. Name 'a', 'b' and 'c' wall layers.
2. Mention the characteristics and function of the cells forming the wall layer 'c'.

Name the kind of organisms which constitute the pioneer community of xerarch and hydrarch successions respectively.

Answer the following questions:
Would Western Ghats ecosystems be less functional if one of its tree frog species is lost forever? Substantiate your answer in the light of hypothesis proposed by Paul Ehrlich.

1. Construct a complete transcription unit with promoter and terminator on the basis of the hypothetical coding strand given below.

2. Write the RNA strand transcribed from the above transcription unit along with its polarity.

Give the names of the hormones released by neurohypophysis.
A boy shows excessive thirst and micturition because of deficiency of a hormone secreted by neurohypophysis. Name the disease he is suffering from.

Name the hormonal composition of the oral contraceptive used by human females. Explain how does it act as a contraceptive?