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प्रश्न
Depending upon the chemical nature of the template (DNA or RNA) and the nature of nucleic acids synthesised from it (DNA or RNA), list the types of nucleic acid polymerases.
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उत्तर
The types of nucleic acid polymerases required for the synthesis of DNA and RNA are:
- DNA polymerase I, II, and III: They help in the replication of DNA.
- RNA-dependent DNA polymerase: It helps in the synthesis of DNA from RNA (reverse transcription).
- DNA-dependent RNA polymerase: It helps synthesise RNA from DNA (transcription).
In eukaryotes, there are at least three RNA polymerases in addition to those found in cell organelles.
- RNA polymerase I transcribes rRNA (28S, 18S and 5.8S).
- RNA polymerase II transcribes the precursor of mRNA called heterogeneous nuclear RNA (hnRNA).
- RNA polymerase III transcribes tRNA, 5SrRNA and snRNAs.
संबंधित प्रश्न
Answer the following question.
Construct and label a transcription unit from which the RNA segment given below has been transcribed. Write the complete name of the enzyme that transcribed this RNA.
Regulatory proteins are the accessory proteins that interact with RNA polymerase and affect its role in transcription. Which of the following statements is correct about regulatory protein?
The most abundant type of RNA in the cell is ______.
The most likely method, used to determine the structural details of the cell organelle is ______.
Which of the following pair lack the unit membrane?
Which enzymes are responsible for the synthesis of tRNA?
The exon part of mRNA has code for ______
What are the functions of methylated guanasine cap?
Give an account of post transcriptional modifications of a eukaryotic mRNA.
Observe the segment of mRNA given below.
(a) Explain and illustrate the steps involved to make fully processed hnRNA?
(b) Gene encoding RNA Polymerase I and III have been affected by mutation in a cell. Explain its impact on the synthesis of a polypeptide, stating the reasons.
- Assertion: Ribosomal RNA is synthesized in the nucleus of the cell.
- Reason: It is translated with the enzyme RNA polymerase III.
Streptokinase produced by bacterium Streptococcus is used for ______.
Given below are two statements:
Statement I: Transfer RNAs and ribosomal RNA do not interact with mRNA.
Statement II: RNA interference (RNAi) takes place in all eukaryotic organisms as a method of cellular defence.
In the light of the above statements, choose the most appropriate answer from the options given below:
During bacterial transcription elongation, what happens to the two DNA strands as RNA polymerase moves forward?
How many DNA strands are read simultaneously by RNA polymerase during bacterial transcription?
Which mechanism of transcription termination in bacteria does not require a protein factor?
Which single enzyme in bacteria synthesizes all types of RNA (mRNA, tRNA, and rRNA)?
At which step of bacterial transcription does the sigma (σ) factor dissociate from the RNA polymerase?
Which DNA sequence element serves as the primary recognition site for the sigma factor in bacterial promoters?
