1. Key Terms in Transcription Coding strand (Sense strand) of dna has the same sequence as mRNA The antisense strand (Template strand) of dna is complementary to the sense strand, and is the one that acts as the template for synthesis of mRNA. RNA polymerases are enzymes that synthesize rna using a dna template(formally described as dNa-dependent rna polymerases) Promoter is a region of dna involved in binding of rna polymerase to initiate transcription Startpoint(Startsite ) refers to the position on DNA corresponding to the first base incorporated into rna Terminator is a sequence of DNA, represented at the end of the transcript, that causes RNa polymerase to terminate transcription
1. Key Terms in Transcription • Coding strand(Sense strand) of DNA has the same sequence as mRNA. • The antisense strand (Template strand) of DNA is complementary to the sense strand, and is the one that acts as the template for synthesis of mRNA. • RNA polymerases are enzymes that synthesize RNA using a DNA template (formally described as DNA-dependent RNA polymerases). • Promoter is a region of DNA involved in binding of RNA polymerase to initiate transcription. • Startpoint (Startsite) refers to the position on DNA corresponding to the first base incorporated into RNA. • Terminator is a sequence of DNA, represented at the end of the transcript, that causes RNA polymerase to terminate transcription
Key Terms in Transcription Transcription unit is the distance between sites of initiation and termination by rna polymerase; may include more than one gene Downstream identifies sequences proceeding farther in the direction of expression for example the coding region is downstream of the initiation codon Upstream identifies sequences proceeding in the opposite direction from expression; for example, the bacterial promoter is upstream from the transcription unit, the initiation codon is upstream of the coding region Primary transcript is the original unmodified rna product corresponding to a transcription unit
Key Terms in Transcription • Transcription unit is the distance between sites of initiation and termination by RNA polymerase; may include more than one gene. • Downstream identifies sequences proceeding farther in the direction of expression; for example, the coding region is downstream of the initiation codon. • Upstream identifies sequences proceeding in the opposite direction from expression; for example, the bacterial promoter is upstream from the transcription unit, the initiation codon is upstream of the coding region. • Primary transcript is the original unmodified RNA product corresponding to a transcription unit
Transcription: similar to replication but different Polymerases use ribonucleotides(NTPs) and Uracil instead of Thymine 2. Produces mainly single-stranded molecules that are complementary to one strand of the DNA template(or non-coding strand) 3. Only part of the genome is transcribed functional genome"or"transcriptome
Transcription: similar to replication but different 1. Polymerases use ribonucleotides (NTPs) and Uracil instead of Thymine 2. Produces mainly single-stranded molecules that are complementary to one strand of the DNA template (or non-coding strand) 3. Only part of the genome is transcribed – “functional genome” or “transcriptome
2. Transcription: Basic Enzymology 1. DNA-dependent RNA Polymerases 2. RNA Pols polymerize in the 5 to 3 direction (rNTP added only to the 3 end) 3. 3 OH of chain reacts with the a po of incoming rNTP, liberating pyrophosphate 4. Added ribonucleotide follows Watson -crick pairing rules, determined by template strand 5. RNA polymerases dont need a primer, but do need DS dna
2. Transcription: Basic Enzymology 1. DNA-dependent RNA Polymerases 2. RNA Pols polymerize in the 5’ to 3’ direction (rNTP added only to the 3’ end) 3. 3’ OH of chain reacts with the a PO4 of incoming rNTP, liberating pyrophosphate 4. Added ribonucleotide follows Watson-Crick pairing rules, determined by template strand 5. RNA polymerases don’t need a primer, but do need DS DNA
E coli rna polymerases(RNAPs a-2 copies 1 copy Core holoenzyme β3 1 cop copy There are multiple forms of o
E. coli RNA polymerases (RNAPs) а- 2 copies b - 1 copy b’ - 1 copy s - 1 copy Core holoenzyme There are multiple forms of s