DNA replication and transcription are the biological processes that help in passing down the genetic information from the parent cell to the identical daughter cells. There are several differences between the two processes but the main difference is while the DNA replication process replicates the DNA to produce DNA, transcription replicates the DNA to produce RNA.

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DNA Replication vs Transcription

The main difference between DNA replication and transcription is that DNA replication is a process where two identical DNA (daughter strands) are formed and each one contains half of the original double helix structure. On the other hand, DNA is used as a template in transcription to synthesize RNA.

DNA replication is the process by which the double helix DNA makes a copy of itself during cell division. From a single DNA, two new DNA strands are formed and each one contains half the original content of the parent DNA. Through the process of DNA replication, genetic information is passed from one generation to the other.

Through the process of transcription, an RNA copy of the gene sequence is produced from the DNA template. Though the RNA formation takes place inside the nucleus, most of the product passes into the cytoplasm from the nucleus. In the cytoplasm, it directs the synthesis of the protein.

Comparison Table Between DNA Replication and Transcription

Parameters of Comparison	DNA Replication	Transcription
Definition	DNA replication is a process through which two daughter strands are produced and each one contains half the original DNA double helix.	Transcription is a process of synthesizing RNA by using DNA double helix as a template.
Occurrence	This process occurs in the S phase of the cell cycle and along the strands of DNA.	This process occurs in the G1 and G2 phases of the cell cycle and along a single strand of DNA.
Purpose	It is essential because the newly formed daughter cells conserve the same genetic information as that of the parent cells.	The RNA that is produced helps in carrying the information required to build a polypeptide.
Enzymes	The enzymes involved in the process are DNA Helicase and DNA Polymerase.	The enzymes involved in the process are transcriptase and RNA polymerase.
Raw materials	dATP, dGTP, dTTP, and dCTP starts the process.	ATP, UTP, GTP, and CTP start the process.
Products	Two identical DNA molecules are formed.	mRNA, tRNA, rRNA, and non-coding RNA are formed.
Primers	DNA replication requires RNA primer to start the process.	No primer is required to initiate the process.
Specific genes	It copies the entire genome.	It copies only certain individual genes.

What is DNA Replication?

DNA replication takes place inside the nucleus of the cell where the double helix DNA structure is unzipped with the help of an enzyme, helicase. It separates the hydrogen bonding between the complementary bases and a “y” shaped structure is formed called the replication fork. These two separate single strands of the same DNA act as templates to form new and identical daughter strands.

During the time of DNA replication, when the strands separate, one strand is called the leading strand and the other one is called the lagging strand. So, the way these two strands get replicated is different. Continuous replication takes place in the leading strand whereas discontinuous (Okazaki fragments) replication takes place in the lagging strand.

DNA replication is the process to pass the identical genetic material from the parent cell to the daughter cells. It also avoids the idea of mutation that can take place due to insertions, substitutions, and deletions.

What is Transcription?

In simple words, transcription is a process through which the information held in a DNA strand is copied into a new molecule of mRNA (messenger RNA). The RNA after formation migrates from the nucleus into the cytoplasm. Though mRNA contains the same information as the DNA strand that was used as a template, the sequence of the mRNA is complimentary.

Transcription takes place in the presence of an enzyme called RNA polymerase along with several accessory proteins that are called transcription factors. These transcription factors bind to specific DNA sequences followed by binding with RNA polymerase to the appropriate transcription site.

Unlike DNA replication, in transcription, only specific individual genomes are copied. The mRNA copies that are formed take part in protein synthesis during translation.

Main Differences Between DNA Replication and Transcription

DNA replication is a process through which two daughter strands are produced and each one contains half the original DNA double helix. On the other hand, transcription is a process of synthesizing RNA by using DNA double helix as a template.
DNA replication occurs in the S phase of the cell cycle and along the strands of DNA whereas transcription occurs in the G1 and G2 phases of the cell cycle and along a single strand of DNA.
DNA replication is essential because the newly formed daughter cells conserve the same genetic information as that of the parent cells whereas the RNA that is produced helps in carrying the information required to build a polypeptide.
The enzymes involved in DNA replication are DNA Helicase and DNA Polymerase whereas the enzymes involved in transcription are transcriptase and RNA polymerase.
dATP, dGTP, dTTP, and dCTP starts DNA replication whereas ATP, UTP, GTP, and CTP start transcription.
Two identical DNA molecules are formed after DNA replication whereas mRNA, tRNA, rRNA, and non-coding RNA are formed after transcription.
DNA replication requires RNA primer to start the process whereas no primer is required to initiate transcription.
DNA replication copies the entire genome whereas transcription copies only specific individual genes.

Conclusion

DNA replication and transcription both start from DNA strands. While in DNA replication, the new identical daughter strands stay inside the nucleus, in transcription, the mRNAs travel into the cytoplasm for protein synthesis.

The formation of identical daughter strands by diving into the double helix DNA (parent strand) makes sure that the entire genetic information is passed to the next generation. It minimizes the chance of any sort of mutation. On the other hand, the RNAs have a copy of the gene’s DNA sequence and they take part in protein formation.

References

https://onlinelibrary.wiley.com/doi/abs/10.1111/j.1365-2958.2012.08102.x
https://www.annualreviews.org/doi/abs/10.1146/annurev.biochem.76.060305.152028