Anonymous
Jul 25
Describe the process of DNA transcription?
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ChatGPT
Jul 25
DNA transcription is the process by which a segment of DNA is copied into a complementary RNA molecule by the enzyme RNA polymerase. The process of transcription can be broken down into several steps:
1. Initiation: RNA polymerase binds to the promoter region of the DNA, which signals the start of transcription. The DNA double helix unwinds, and the enzyme begins to synthesize a complementary RNA strand using one of the DNA strands as a template.
2. Elongation: As RNA polymerase moves along the DNA template, it adds nucleotides to the growing RNA strand according to the base-pairing rules (A pairs with U, G pairs with C). The enzyme continues to unwind the DNA ahead of it and rewind it behind it as it synthesizes the RNA molecule.
3. Termination: Transcription continues until the RNA polymerase reaches a termination signal in the DNA sequence. This signal causes the enzyme to release the RNA molecule and detach from the DNA template.
4. Processing: The newly synthesized RNA molecule, called pre-mRNA, undergoes several processing steps before it can be used by the cell. These steps include the addition of a 5' cap and a poly-A tail, as well as the removal of introns through a process called splicing.
5. mRNA export: The mature mRNA molecule is then exported from the nucleus to the cytoplasm, where it can be translated into a protein by ribosomes.
Overall, DNA transcription is a crucial process that allows genetic information stored in the DNA to be converted into functional proteins that carry out various cellular functions.
1. Initiation: RNA polymerase binds to the promoter region of the DNA, which signals the start of transcription. The DNA double helix unwinds, and the enzyme begins to synthesize a complementary RNA strand using one of the DNA strands as a template.
2. Elongation: As RNA polymerase moves along the DNA template, it adds nucleotides to the growing RNA strand according to the base-pairing rules (A pairs with U, G pairs with C). The enzyme continues to unwind the DNA ahead of it and rewind it behind it as it synthesizes the RNA molecule.
3. Termination: Transcription continues until the RNA polymerase reaches a termination signal in the DNA sequence. This signal causes the enzyme to release the RNA molecule and detach from the DNA template.
4. Processing: The newly synthesized RNA molecule, called pre-mRNA, undergoes several processing steps before it can be used by the cell. These steps include the addition of a 5' cap and a poly-A tail, as well as the removal of introns through a process called splicing.
5. mRNA export: The mature mRNA molecule is then exported from the nucleus to the cytoplasm, where it can be translated into a protein by ribosomes.
Overall, DNA transcription is a crucial process that allows genetic information stored in the DNA to be converted into functional proteins that carry out various cellular functions.
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Google Gemini AI
Jul 25
DNA Transcription
DNA transcription is the process by which the genetic information stored in DNA is copied into RNA (ribonucleic acid). RNA is a single-stranded molecule that carries copies of the specific genes from DNA to the part of the cell where protein synthesis occurs.
Steps of DNA Transcription:
1. Initiation:
- RNA polymerase binds to a specific DNA sequence called the promoter, located upstream of the gene to be transcribed.
- The enzyme unwinds the DNA helix, separating the two strands.
2. Elongation:
- RNA polymerase moves along the DNA template strand, using it as a guide.
- RNA nucleotides (adenine, cytosine, guanine, uracil) pair with their complementary DNA nucleotides (T replaced by U in RNA).
- A new RNA strand is synthesized in the 5' to 3' direction, complementary to the DNA template strand.
3. Termination:
- When RNA polymerase reaches a specific termination sequence in the DNA, it releases the RNA transcript.
- The DNA strands re-anneal, and the RNA polymerase dissociates from the DNA.
Types of RNA Produced:
- Messenger RNA (mRNA): Carries the genetic code from the nucleus to the ribosomes, where protein synthesis occurs.
- Transfer RNA (tRNA): Transports amino acids to the ribosomes to form polypeptide chains.
- Ribosomal RNA (rRNA): Forms the core of ribosomes, which are the sites of protein synthesis.
Key Features of Transcription:
- Transcription is semi-conservative: Only one DNA strand is used as the template, and the resulting RNA molecule is complementary to that strand.
- Transcription can occur multiple times from the same DNA template.
- Different RNA polymerases are responsible for transcribing different types of RNA.
- The rate of transcription is regulated by various factors, including the availability of RNA polymerase and the presence of regulatory elements in the DNA.
DNA transcription is the process by which the genetic information stored in DNA is copied into RNA (ribonucleic acid). RNA is a single-stranded molecule that carries copies of the specific genes from DNA to the part of the cell where protein synthesis occurs.
Steps of DNA Transcription:
1. Initiation:
- RNA polymerase binds to a specific DNA sequence called the promoter, located upstream of the gene to be transcribed.
- The enzyme unwinds the DNA helix, separating the two strands.
2. Elongation:
- RNA polymerase moves along the DNA template strand, using it as a guide.
- RNA nucleotides (adenine, cytosine, guanine, uracil) pair with their complementary DNA nucleotides (T replaced by U in RNA).
- A new RNA strand is synthesized in the 5' to 3' direction, complementary to the DNA template strand.
3. Termination:
- When RNA polymerase reaches a specific termination sequence in the DNA, it releases the RNA transcript.
- The DNA strands re-anneal, and the RNA polymerase dissociates from the DNA.
Types of RNA Produced:
- Messenger RNA (mRNA): Carries the genetic code from the nucleus to the ribosomes, where protein synthesis occurs.
- Transfer RNA (tRNA): Transports amino acids to the ribosomes to form polypeptide chains.
- Ribosomal RNA (rRNA): Forms the core of ribosomes, which are the sites of protein synthesis.
Key Features of Transcription:
- Transcription is semi-conservative: Only one DNA strand is used as the template, and the resulting RNA molecule is complementary to that strand.
- Transcription can occur multiple times from the same DNA template.
- Different RNA polymerases are responsible for transcribing different types of RNA.
- The rate of transcription is regulated by various factors, including the availability of RNA polymerase and the presence of regulatory elements in the DNA.
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