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प्रश्न
Which of the following statements is correct about the role of regulatory proteins in transcription in prokaryotes?
विकल्प
They only increase expression
They only decrease expression
They interact with RNA polymerase but do not affect the expression
They can act both as activators and as repressors
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उत्तर
They can act both as activators and as repressors
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संबंधित प्रश्न
In E.coli, three enzymes β- galactosidase, permease and transacetylase are produced in the presence of lactose. Explain why the enzymes are not synthesized in the absence of lactose.
Distinguish between structural gene, regulatory gene and operator gene.
A low level of expression of lac operon occurs at all the time. Justify the statement.
______ refers to the phenomenon by which a set of genes are switched on when there is necessity to metabolise a new substrate.
Identify the process described in the following paragraph.
Repressible regulation of gene is seen when the end product of a biosyntbetic pathway like amino acid, is provided in the medium. At this time, internal biosynthesis of amino acid stops. It is negative control so the metabolite (amino acid) turns off a set of genes involved in producing that metabolite.
Which of the following factors regulate gene expression?
Which of the following is not a level at which gene expression can be regulated in eukaryotes?
Sometimes cattle or even human beings give birth to their young ones that are having extremely different sets of organs like limbs/position of eye(s) etc. Comment.
The gene which codes for enzyme β-galactosidase ______.
The image below shows the result of plating bacteria in a chromogenic medium after incorporating the gene of interest in the plasmid. Some plates had blue colonies; some plates had white colonies. A single bacterium extracted from Plate I, II, and III is shown below:
On the basis of your observations:
- Identify the plate(s) which is/are white. Give a reason.
- Identify the plate(s) which is/are blue. Give a reason.
Which of the following are the post-transcriptional events in an eukaryotic cell?
- Transport of pre-mRNA to cytoplasm prior to splicing.
- Removal of introns and joining of exons.
- Addition of methyl group at 5' end of hnRNA.
- Addition of adenine residues at 3' end of hnRNA.
- Base pairing of two complementary RNAs.
Choose the correct answer from the options given below:
Which of the following best describes gene regulation?
At how many levels can gene regulation occur in eukaryotes?
Which level of gene regulation involves the formation of the primary transcript in eukaryotes?
Which level of gene regulation specifically controls splicing in eukaryotes?
Which level of gene regulation involves the movement of mRNA from the nucleus to the cytoplasm?
At which level of gene regulation is control exerted during protein synthesis in eukaryotes?
What is feedback repression?
Which type of control is exemplified by feedback repression?
