Match List – I with List – II.
|
LIST I |
LIST II |
|
A. RNA Polymerase I |
I. Transcription of hnRNA |
|
B. RNA Polymerase II |
II. Polymerisation in 5' to 3' direction |
|
C. RNA Polymerase III |
III. Transcription of rRNAs 28S,18S,5.8S) |
|
D. DNA dependent RNA Polymerase |
IV. Transcription of tRNA, 5srRNA, snRNA |
Choose the correct answer from the options given below:
Answer & explanation
Correct answer: option 4
The correct answer is Option (4) →A-III, B-I, C-IV, D-II
|
LIST I |
LIST II |
|
A. RNA Polymerase I |
III. Transcription of rRNAs 28S,18S,5.8S) |
|
B. RNA Polymerase II |
I. Transcription of hnRNA |
|
C. RNA Polymerase III |
IV. Transcription of tRNA, 5srRNA, snRNA |
|
D. DNA-dependent RNA Polymerase |
II. Polymerisation in 5' to 3' direction |
In eukaryotes, there are at least three RNA polymerases in the nucleus (in addition to the RNA polymerase found in the organelles). There is a clear cut division of labour.
The RNA polymerase I transcribes rRNAs (28S, 18S, and 5.8S), whereas the RNA polymerase III is responsible for transcription of tRNA, 5srRNA, and snRNAs (small nuclear RNAs).
The RNA polymerase II transcribes precursor of mRNA, the heterogeneous nuclear RNA (hnRNA).
The process of copying genetic information from one strand of the DNA into RNA is termed as transcription. A transcription unit in DNA is defined primarily by the three regions in the DNA :
(i) A Promoter
(ii) The Structural gene
(iii) A Terminator
There is a convention in defining the two strands of the DNA in the structural gene of a transcription unit. Since the two strands have opposite polarity and the DNA-dependent RNA polymerase also catalyse the polymerisation in only one direction, that is, 5' →3' , the strand that has the polarity 3' →5' acts as a template, and is also referred to as template strand. The other strand which has the polarity (5' →3' ) and the sequence same as RNA (except thymine at the place of uracil), is displaced during transcription.