Transcription of RNA

•Initiated by proteins → basal transcription factors • Match RNA pol with appropriate promoter region in DNA ↓ transcribes only template strand RNA Processing in Eukaryotes • Eukaryotic cells contain 3 types of RNA polymerases: . Only RNA polymerase2.Transcription initiation complex•Collection of•Regulatory protein binded to promoter•Involved in regulating transcription(↑transcripts created) Repressors reduce/inhibit transcription by preventing activators from binding or by binding to specific repressor regions •RNA polymerase untwists DNA double helix Approximately 10 to 20 bases exposed at a time RNA pol catalyzes the addition of RNA bases in 5' to 3' direction to create the mRNA transcript will be degraded 5' Guanine Cap is added immediately otherwise RNA transcript recognition signal for the translation machinery •Aids in attachment to ribosome for translation Transcription Termination Eukaryotes: RNA nucleotide sequence called the polyadenylation signal sequence is transcribed by the RNA polymerase • mRNA is released from the RNA pol Precursor mRNA is not ready for translation ! 3' Poly A Tail •poly (A) polymerase adds a poly A tail (50 to 250 adenine nucleotides) a poly A tail (50 to 250 •String of adenine at 3' end of mRNA •Added post transcriptionaly (before mRNA leaves nucleus) •Protects mRNA from nucleases, phosphatases that are present in cytoplasm (degradation) facilitates export of the mRNA from nucleus through a nuclear pore UTRs (untranslated regions) • Present on template DNA strand 5' and 3' mRNA nucleotide sequences that will not be translated into part of the polypeptide template DNA strand •Important for binding to the ribosome DNA RNA --> protein transcription ATP 3 phosphate Sugar (Ribose) Hydroxyl (Adine) Amino Acids H NH2 - C - COOH R 1 2 dehydration H2O Chromatin DNA + protein Euchromatin = loosely packed (active) Heterochromatin = densely packed (inactive) • Histone Proteins • Basic AA's • Histone 1 (H1) Cytoskeletal Filaments Name of Filament Monomer Structure Function Molecular Motor Intermediate N/A Structure (nuclear lamina) N/A N/A Microtubules Vesicular, DNA, and cell movement Kinesin away from centrosome Dynein towards centrosome Actin Microfilaments Cell movement Myosin Cell cleavage Distribution of Energy Enthalpy (H) Increases Entropy (S) Decreases Cellular Respiration generates ATP Substrate Phosphorylation Transfer of phosphate from TE to substrate ADP Oxidative Phosphorylation ATP created with ADP + phosphate by ATP synthase (proton gradient for E) monomer Enthalpy (H) Decreases Entropy (S) Increases polymer