Question

what different purposes between the DNA replication and Transcription.

what enzymes be used on DNA replication(at least 3 types) and Transcription(at least 2 types).

Answer 1

Different Purposes between DNA replication and transcription   :-

purposes of DNA replication:-

1.Replication is the basis of biological inheritance.

2.Replication is responsible for copying of DNA.It's purpose is to form DNA having one parental strand and one newly synthesised strand.Two replicas are formed by this process,which are equally distributed to two new cell that are formed after cell division.

3.Replication plays vital role in cell division.it's main purpose is to have same genes in the progeny after the reproduction.

Purposes of transcription:-

1.Transcription plays vital role in regulating gene expression.

2..The purpose of transcription is to produce an mRNA copy of a gene.It is the process of copying genetic information from one strand of the DNA into RNA .unlike replication,only single stranded fragment of DNA gets copied into RNA.

3.mRNA is required in formation of particular protein.it translated into protein.so,transcription plays vital role in gene expression by forming mRNA.

Enzymes used in DNA replication:-

i.DNA-dependent DNA polymerase:-It catalysts the polymerisation of deoxynucleotides on DNA template.

ii.Helicase:-It unwinds the DNA strand to form the replication fork.

iii.DNA ligase:-It joins the okazaki fragments which are formed on the lagging strand.

iv.Primase:-It initiates replication of the strand oriented in the 3' to 5' direction.

Enzymes used in transcription:-

i.RNA polymerase:-It is the main enzyme in transcription.it binds to the promoter region in order to initiate transcription.In bacteria ,the transcription of all the three types of RNA (mRNA,tRNA,rRNA)is catalysed by single DNA-dependent enzyme that is RNA polymerase.

ii.In eukaryotes three types of RNA polymerase are found in nucleus,RNA polymerase I(transcribes rRNAs),RNA polymerase II(transcribes the precursor of mRNA),RNA polymerase III(transcribes tRNA,5S rRNA and snRNAs).