Transcription

• Genome


  All the genes on the DNA of an Organisms or Species
• Proteome


  All the proteins that can be made by one organism or species
• Where does Transcription occur?


  Nucleus
• Stage 1 - RNA Polymerase binds to section of the DNA called the promoter region near the start codon
• Stage 2 - The hydrogen bonds between complementary DNA bases are broken by DNA Helicase, so that the DNA is unzipped
• Stage 3 - One strand is used as a template strand; mRNA nucleotides in the nucleus bind to complementary DNA bases by hydrogen bonds
• Stage 4 - RNA Polymerase forms bonds between mRNA nucleotides to form pre-mRNA
• Stage 5 - DNA strand rejoins behind the newly formed pre-mRNA strand
• Stage 6 - When RNA Polymerase reaches a stop codon, it detatches from the pre-mRNA, and the pre-mRNA strand is complete
• Stage 7 - Introns are removed by enzymes in a process known as splicing to form mature mRNA
• What are Exons?


  Coding sequences of DNA
• What are Introns?


  Non-coding sequences of DNA
• What do Prokaryotes not have?


  Introns - splicing not required