Question

Problem 2 (5 marks) Gene expression can be regulated at 3 levels. Which are these 3 levels? Which mode of regulation is the slowest in response to time, and which is faster? Which is the most efficient in resource use? Explain.

Answer 1

KAINA : 4V can be regulated at 3 levels Answer Gene expression Transcriptional > Post-transcriptional " Post- translational In transcriptional regulation, the transcription of the gene at the level of DNA ees regulated. Based on the requirement of the cell, the transcription of the gene make the mRNA e made from the DNA to Tt mainly involves the use of repressor on or off ... olecules that binds to the operator region and prevents the mbase to initiate branscription. But poo RNA poly- when the condition in favourable the the repressor is made inactive and hence transcription can initiate na C regulation to Post-franscriptional and takes blace at the mRNA level, ie the transcri- a of the ption of the gene to mRNA have already gene place. taken represson In this case, as molecules bunds to some specific sequence IDNA to prevent transcription similarki g certain pen regulatory proteins bind i the the MRNA an mRNA and procent to sequences on their translation.. ha regulate This mode of regulation is less efficient and also a occurs less frequente Post - translational regulation takes place after the mRNA has been translated onito proteins. This regulation is based on the on the modifications made rotein such as phosphorylation, on the methylation, acetylation ele rotein that actually makes the protein ready for functioning. Otherwise the protein is not folded property and hence degraded by proteasomal machinery regs less frequently

The post-translational valustadion is the regulation, Slowest in response to time and moreover it is far less efficient than the other 2 methods of regulation. W Do The transcriptional regulation is the fastest with respect to time, as it is much more efficient process as compared to the other 2 methods. The transcriptional mode of regulation is the most efficient mettrad a g in resource use. This is because , et prevents the formation of mRNA from the DNA which o the very initial step of gene expression in the gene product is not necessary o the cell: This prevents the loss of rees in the cell for and the product which is necessary. This Keeps the actually not But in case I control post of halten post transcriptional and post-translational ene regulation, the regulation is made has been abready formed the to when energy and resources in te maket making the product we not gene expression at a regulatoru crary loss of energy urces opticient and hence they are o at resource use no as out only to regulaló, after the product has been abready which causes unnecessary loss of and resources and he not efficient at rese regielation is parkeren product formation for efficient use of resource and energy and prevent unnecessary loss of resources that puts a strain on the cell.. the proa

The regulation of gene expression is extremely necessary to control the level of synthesis and acccumulation of gene product according to the need of the cell .The expression which takes place all the time irrespective of any condition in the cell is called Constitutive expression .The Loss of regulatory control can make some genes constitutive which may result in drastic result that may be harmful to the organism.Cancer is the result of failure of some regulatory mechanisms in cell cycle pathway.