BIOB 110CS 1st Edition Lecture 19 Central Dogma and Gene Expression DNA contains all info needed for an organisms Every cell contains the same DNA yet all cells are not the same Selective gene expression confers individuality to a cell turns on different genes Adenine pairs with thymine and cytosine pairs with guanine these are the four nucleotides that make up DNA DNA strands in a helix are anti parallel lower strand is the reverse complement of the upper strand DNA replication Semi constructive in new DNA strand half is new and half is old Occurs before each division in interphase daughter cell contains same amount of DNA as the mother cell DNA polymerase makes polymers is an enzyme carries out replication Mutations in DNA Errors made by DNA polymerase UV radiation x rays gamma rays chemical mutagens dioxin all can cause mutations The central dogma Transcription happens first followed by translation DNA and RNA RNA uses Uracil U instead of T thymine DNA is double stranded RNA is single stranded These notes represent a detailed interpretation of the professor s lecture GradeBuddy is best used as a supplement to your own notes not as a substitute DNA is long living RNA is used and then degrades quickly labile G Gene expression is initiated when RNA polymerase binds to a promoter sequence upstream from a gene The promoter controls where when and how much of the gene is made Introns intervene sequence are in eukaryotic genes and have to be removed from the nucleus before mRNA is transported to the cytoplasm Exon sequence that exit the nucleus Mature mRNAs are translated into proteins polypeptides by ribosomes and is in groups of three called codons Codons encode start signals amino acids and stop signals
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