DNA replication and transcription are the biological processes that help in passing down 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.
Key Takeaways
- DNA replication is the process of copying the entire DNA sequence, while transcription is the process of making an RNA copy of a specific gene.
- Replication occurs in the S-phase of the cell cycle, while transcription occurs throughout the interphase.
- Replication requires multiple enzymes, including helicase and DNA polymerase, while transcription requires RNA polymerase and several transcription factors.
DNA Replication vs Transcription
DNA replication is the process by which a cell makes an exact copy of its DNA and is essential for the transmission of genetic information from one generation to the next. Transcription is the first step in gene expression by which genetic information in DNA is used to synthesize RNA molecules.
DNA replication is the process by which the double helix DNA makes a copy of itself during cell division.
Two new DNA strands are formed from a single DNA, 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
| 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 DNA replication, when the strands separate, one strand is called the leading strand, and the other is called the lagging strand.
So, the way these two strands get replicated is different. Continuous replication occurs in the leading strand, whereas discontinuous (Okazaki fragments) replication occurs in the lagging strand.
DNA replication is the process of passing 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 used as a template, the mRNA sequence is complementary.
Transcription occurs in the presence of an enzyme called RNA polymerase and several accessory proteins called transcription factors.
These transcription factors bind to specific DNA sequences and bind 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, each containing half the original DNA double helix. On the other hand, transcription is a process of synthesizing RNA by using a 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.
- 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
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