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प्रश्न
Define a cistron. Giving examples differentiate between monocistronic and polycistronic transcription unit.
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उत्तर
Portion of DNA having information for an entire polypeptide or trait is called cistron. However, by defining a cistron as a segment of DNA coding for a polypeptide, the structural gene in a transcription unit could be said as monocistronic (mostly in eukaryotes) or polycistronic (mostly in bacteria or prokaryotes). In eukaryotes, the monocistronic structural genes have interrupted coding sequences—the genes in eukaryotes are split.
The coding sequences or expressed sequences are defined as exons. Exons are said to be those sequence that appear in mature or processed RNA. The exons are interrupted by introns. Introns or intervening sequences do not appear in mature or processed RNA.
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संबंधित प्रश्न
What is a cistron?
Explain (in one or two lines) the function of the following:
Exons
The correct sequence of gene expression is:
- Formation of the primary transcript
- Regulation of splicing
- Transport of mRNA from the nucleus to the cytoplasm
- Translation
The transcription unit is represented in the diagram given below.
Identify site (i), factor (ii), and Enzyme (iii) responsible for carrying out the process.
Gene is:
The functional unit of DNA molecule that codes for particular gene product is ______.
Exons help in synthesis of ______.
Do you think that the alternate splicing of exons may enable a structural gene to code for several isoproteins from one and the same gene? If yes, how? If not, why so?
Frequency of recombination between gene pairs on same chromosome as a measure of the distance between genes to map their position on chromosome, was used for the first time by ______.
In prokaryotes, which of the following DNA sequences is typically found in the promoter region?
The Coding Strand is also known by which alternative names?
What is the relationship between the Coding Strand sequence and the mRNA sequence produced during transcription?
With respect to which strand are all coordinates such as 'upstream' and 'downstream' defined in a transcription unit?
Which organism type typically produces Polycistronic mRNA?
The Lac operon in E. coli is an example of which type of mRNA?
In the context of a transcription unit, how do the Promoter and Terminator work together to regulate the transcription process?
