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Replication is the process of making two identical DNA molecules from a double-stranded DNA molecule. One of the most important things that happens in a cell is when DNA is made. The process of transcribing information from a strand of DNA into a new messenger RNA molecule is known as transcription (mRNA). A template, or reference, is kept in the nucleus of cells by DNA, which keeps the genetic material there in a secure and stable way.
Replication:
The biological process of copying or making an exact copy, such as a polynucleotide strand, is known as replication (DNA). One of the most important biological processes in all living organisms is DNA replication. It is a molecular process that occurs in dividing cells and involves the replication of DNA. In biology, the term “replication” also refers to performing the same technique. A good example of this is the repetition of a laboratory procedure. In scientific studies and statistics, replicates are required to draw a more precise conclusion from the experimental results .
Steps of DNA Replication :
Step 1: Identification of the origin of replication (ori)
It’s at this point that DNA replication starts. The ori binding proteins bind to an AT-rich section of DNA just near to ori. At ori, the ori binding proteins unwind the DNA. The single-strand binding proteins (SSB) stabilise the unravelled DNA and prevent it from reannealing .
Step 2: The unwinding of the DNA
The enzyme helicase is responsible for subsequent DNA unwinding. Supercoiling happens upstream of the replication fork and is handled by the enzyme topoisomerase as the helicase enzyme works .
Step 3: Formation of the replication fork
A replication bubble is generated when the DNA is unwound. Replication forks are the two halves of this replication bubble .
Step 4: Actual DNA synthesis
An enzyme called primase first creates a 10-nucleotide long RNA primer, which DNA polymerase III then adds further nucleotides to. Later, DNA polymerase I removes the primer and fills the gap that has been produced .
Step 5: Termination of DNA replication
Following the replication of DNA, specialised termination sequences known as ter help in the termination of the replication process. The ter sequence, also known as terminator utilisation sequence, is bound by the tus proteins. Tus proteins serve as anti-helicases, preventing DNA replication .
Transcription:
The process of making RNA from DNA is known as transcriptionDNA sends information about an organism’s genes to protein, the material that makes it look like a living thing. The process of transcription (turning DNA into RNA) and translation are what make this information move (RNA to protein) . When a specific gene product is required at a certain time or in a specific tissue, transcription occurs .
Difference between replication and transcription:
Replication | Transcription |
It passes on the whole genome to its descendants . | It makes RNA copies of a certain gene . |
Topoisomerase, Helicase, DNA primase, and DNA ligase are some of the enzymes found in the human body. | RNA polymerase and transcriptase (a form of DNA helicase). |
It happens during the S phase, when the cell is prepared to divide . | When the cell needs to synthesise proteins, it happens in the G1 and G2 phases . |
As precursors, it uses dATP, dGTP, dTTP, and dCTP. | As precursors, it uses ATP, UTP, GTP, and CTP. |
Through its 3′ to 5′ exonuclease action, DNA polymerase maintains high fidelity . | When compared to DNA polymerase, RNA polymerase has lower fidelity . |
It can make very long DNA strands . | It makes RNA strands that are quite short . |
Hydrogen bonds hold a new DNA strand to its template when it is made. | RNA that has been transcribed splits from its template. |
For the replication to begin, DNA polymerase requires an RNA primer . | No primers are required by RNA polymerase . |
There are two daughter strands formed. | It produces mRNA, tRNA, rRNA, and non-coding RNA like microRNA. |
There is no processing of newly synthesised DNA. | Post-transcriptional changes are made to transcribed RNAs. |
Replicated DNA is passed down through the generations. | Even before they can function, most RNAs are destroyed. |
DNA that has been replicated remains in the nucleus. | The majority of the product is absorbed by the cytoplasm. |
Conclusion:
In a cell, both DNA replication and transcription require making a new copy of the DNA. DNA transcription is involved in the conversion of DNA to RNA, whereas DNA replication is the process of making another copy of DNA. In the synthesis of new nucleic acids, either DNA or RNA, both processes are involved. The newly created nucleic acids are identical in appearance but differ in function. One is responsible for cell division, while the other is responsible for gene expression .
