DNA is a polymer of nucleotides which are linked to each other by $3^{\prime}-5^{\prime}$ phosphodiester bond. To prevent polymerisation of nucleotides, which of the following modifications would you choose?
Replace purine with pyrimindines
Remove/Replace 3' OH group in deoxy ribose
Remove/Replace 2' OH group with some other group in deoxy ribose
Both (b) and (c)
Discontinuous synthesis of DNA occurs in one strand, because
DNA molecule being synthesised is very long
DNA dependent DNA polymerase catalyses polymerisation only in one direction ( $5^{\prime} \rightarrow 3^{\prime}$ )
it is a more efficient process
DNA ligase has to have a role
Which of the following steps in transcription is catalysed by RNA polymerse?
Initiation
Elongation
Termination
All of these
Control of gene expression takes place at the level of
DNA-replication
transcription
translation
None of these
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?
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