LC 06: Transcription

• Genes transcribed into RNA

  • mRNA
  • tRNA
  • rRNA
• Gene


  Segments of DNA transcribed into RNA, may or may not encode for protein
• Some RNAs actually stop the production of proteins
• The molecular definition of a gene is the entire nucleic acid sequence necessary for the synthesis of a protein and its variants or RNA
• There are two types of genes: one where the resulting RNA encodes for a protein, and the other where the resulting RNA functions as RNA and may not be translated into protein
• Some RNAs function as RNA and may not be translated into protein
• All RNAs come from genes, which can be transcribed into RNA, some encoding for proteins and some functioning as RNA
• Genes

  • They are transcribed but not always result in protein production
• Transcription

  • RNA polymerase catalyzes the sequential addition of ribonucleotides from 5' to 3'
• Genes are transcribed but doesn't necessarily make protein
• Uracil can be found in DNA due to DNA damage
• RNA is made in the 5' to 3' direction
• Ribonucleoside triphosphates (ATP, UTP, CTP, GTP) are used in RNA synthesis
• Some RNAs encode for protein while others are just RNAs like TR RNA, R RNA, T RNA, and other RNAs
• Deoxyribose in DNA does not mean there is no oxygen present
• Transcription and translation

  Genes are transcribed into mRNA which is then translated into protein
• RNA is made anti-parallel and complementary to DNA
• RNA nucleotides are added in the 5' to 3' direction
• A DNA-RNA Helix is formed during RNA transcription
• RNA polymerases use ribonucleoside triphosphates, while DNA polymerase uses deoxyribonucleoside triphosphates
• RNA polymerase works similarly to DNA polymerase
• RNA nucleotides are linked by phosphodiester bonds, similar to DNA
• The DNA template is read three prime to five prime
• Ribonucleoside triphosphates are added to the RNA transcript by RNA polymerase
• RNA polymerase transcribes the DNA double helix in bacteria
• Ribonucleoside triphosphates are cut off two phosphate groups before being added to the RNA transcript
• Generation of an RNA transcript involves separating the two strands of single-stranded DNA, reading a strand of DNA, and linking RNA nucleotides by phosphodiester bonds
• RNA is made in the five Prime to three prime Direction adding on to the three prime end
• RNA polymerase synthesizes the newly synthesized RNA transcript
• Base pairing dictates the addition of nucleotides in RNA transcription
• Base pairing directs the way RNA is made
• Base pairing dictates the addition of ribonucleoside triphosphates in RNA transcription
• Base pairing continues to dictate the addition of nucleotides after the active site in RNA transcription
• RNA compares quite nicely to DNA polymerase


  It follows similar rules
• RNA polymerase is abbreviated as RNAP
• DNA or bacterial DNA is not half DNA half RNA
• RNA polymerase has a ribonucleoside triphosphate uptake Channel where ribonucleoside triphosphates come in at the active site
• Sigma Factor binds the RNA polymerase and finds the promoter sequence
• Phosphates adding in the next phosphate sugar base and of course base pairing is dictating what comes in next
• Sigma Factor recognizes the promoter and leads to localized unwinding of DNA