Difference between DNA Replication and Transcription

Making copies of DNA in the cell is essential in the life process. There are different ways of doing so and the common ones are transcription and DNA replication. DNA replication is the process of making another copy of DNA while transcription copies the DNA into RNA.

Both have similarities and differences. We are going to tackle the differences and similarities between the two in this article.

Image 1: The image shows how a DNA transcription takes place.

Picture Source: encrypted-tbn0.gstatic.com

What is transcription?

It involves making a copy of DNA into RNA. The part of DNA that codes for genes is copied into the messenger RNA. The two strands of DNA helix are unwind and separated. The RNA polymerase, a special type of enzyme travels along the strands of DNA and binds RNA nucleotides to it until it forms a complete strand of messenger RNA.

The messenger RNA also known as mRNA is the cell’s blueprint, which is used to construct a specific type of protein. The mRNA travels from the nucleus to the cytoplasm where the gene expression takes place. ^{(1, 2, 3, and 4)}

Image 2: An image presentation on how DNA replication takes place.

Picture Source: wikimedia.org

 

What is DNA Replication?

It pertains to the process of copying the DNA in the cell to produce two copies. DNA replication is vital for cell division or mitosis. Before the cell division takes place, the DNA must be copied so the resulting daughter cells have the same copy of DNA. The DNA is unwind to separate the two strands of helix. The DNA polymerase travels along each strand and bind the complementary nucleotides – the DNA’s building block. It results in two double-stranded helices. ^{(4, 5)}

Image 3: A comparison image between DNA replication and transcription.

Picture Source: encrypted-tbn0.gstatic.com

Image 4: The image represents how DNA replication and transcription take place.

Picture Source: encrypted-tbn0.gstatic.com

 

Are there any similarities?

1. They both involve binding complementary nucleic acids to DNA which results in the formation of a new strand of either RNA or DNA.
2. The possibility of error is always there for both DNA replication and transcription. Error is possible if a wrong nucleotide is incorporated. An error in the DNA process could result in a wrong protein sequence translation. ^{(4, 5, and 6)}

Let us take a look at the differences between DNA replication and transcription.

Definition

• DNA Replication – The process of creating two daughter strands and each strand has half of the original DNA double helix.
• Transcription – It is the synthesis of RNA with the use of DNA.

Uses/Purpose

• DNA Replication – The purpose of DNA replication is to conserve genome for the next generation.
• Transcription – The purpose of transcription is to create RNA copies of individual genes.

Enzyme Requirements

• DNA Replication – DNA polymerase and DNA helicase
• Transcription – RNA polymerase and transcriptase ^{(6, 7)}

Occurrence

• DNA Replication – It takes place in the S phase cell cycle, along the strands of DNA, and in preparation for the cell division.
• Transcription – It takes place in the G1 and G2 phases of the cell’s cycle, along one strand of the DNA, and preparation for translation of protein.

Bond

• DNA Replication – The replicated DNA strands remains hydrogen bonded to the DNA strand.
• Transcription – The transcribed RNA strand has separated from the DNA template strand.

Primers

• DNA Replication – For DNA replication to take place, it needs RNA primer.
• Transcription – Transcription can occur even without a primer.

Resulting Products

• DNA Replication – The process would result in the formation of two daughter strands, which remain within the nucleus and do not degrade.
• Transcription – It results in the formation of different kinds of RNA like the rRNA, tRNA, and mRNA. In fact, even non-coding RNA becomes a product too. These products pass from the nucleus into the cytoplasm. Unlike replication, the products of transcription are degraded once they already perform their functions. ^{(8, 9, and 10)}

Copying

• DNA Replication – The entire genome is copied.
• Transcription – It only copies a certain type of individual genes.

Processing

• DNA Replication – It leads to a normal DNA molecule, which makes processing no longer needed.
• Transcription – The process leads to the primary RNA transcript molecule that needs to be processed to reach the final form and size.

Unwinding and Splitting 

• DNA Replication – The entire DNA is split and unwind.
• Transcription – Unwinding and splitting only occurred on genes that need to be transcribed. ^{(2, 4, 7, and 8)}

Differences between DNA replication and transcription in detail.

Characteristic	DNA Replication	Transcription
Definition	The creation of two daughter strands with each strand containing half of the original DNA double helix.	The synthesis of RNA using DNA.
Uses	For conservation of genome for the next generation.	For creating RNA copies of individual genes.
Enzyme requirements	DNA polymerase and DNA helicase	RNA polymerase and transcriptase
Occurrence	In the S phase cell cycle, along the strands of DNA, and in preparation for the cell division.	In the G1 and G2 phases of the cell’s cycle, along one strand of the DNA, and preparation for translation of protein.
Bond	Replicated DNA strands remains hydrogen bonded to the DNA strand.	Transcribed RNA strand has separated from the DNA template strand.
Primers	It needs an RNA primer.	Primer is not needed.
Resulting Products	Two daughter strands	Different kinds of RNA like rRNA, tRNA, mRNA, and non-coding RNA
Copying	The whole genome is copied.	Copies a particular type of individual genes.
Processing	Normal DNA molecule – processing is not needed.	The primary RNA transcript molecule needs to be processed.
Unwinding and Splitting	The DNA is split and unwind.	Only genes to be transcribed need unwinding and splitting.

DNA replication is a part of cell division. It is essential in regulating the cell’s growth and division. If the cell lacks a particular growth factor, the replication process will not take place. On the other hand, DNA transcription regulates gene expression. Transcription only takes place when a gene is turned on.

References

1. https://sciencing.com/difference-between-transcription-dna-replication-9038.html
2. https://microbiologyinfo.com/difference-replication-transcription/
3. https://www.atdbio.com/content/14/Transcription-Translation-and-Replication
4. https://biodifferences.com/difference-between-replication-and-transcription.html
5. https://www.diffen.com/difference/Replication_vs_Transcription
6. https://www.nature.com/scitable/topicpage/dna-transcription-426/
7. https://microbenotes.com/differences-between-dna-replication-and-transcription/
8. https://vivadifferences.com/replication-vs-transcription/
9. https://www.majordifferences.com/2013/10/difference-replication-vs-and.html#.XaPdcS2B3fY
10. https://pediaa.com/difference-between-dna-replication-and-transcription/