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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
Explain the process of transcription in Eukaryotes.
Explain the process of making heterogeneous nuclear RNA (hnRNA) into a fully functional mRNA in eukaryotes. Where does this process occur in the cell?
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 amino acid attaches to the tRNA at its ______.
To initiate translation, the mRNA first binds to ______.
A special feature of viruses is that they:
Ribozyme is a/an:
The most abundant type of RNA in the cell is ______.
Sigma factor is a component of ______.
A ribozyme is an:
The exon part of mRNA has code for ______
Identify the correct statement.
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 ______.
