using RNA for protein - 

• ribosomes - RNA-protein complexes that make polypeptides
  • has 2 subunits
  • RNA acts as main catalytic unit, ribosomal proteins has structural role
  • protein synthesis occurs at P, A, and E sites
• ribosomal RNA (rRNA) - type of RNA in ribosomes
  • provides the site where polypeptides get assembled
• transfer RNA (tRNA) - transports/positions amino acids
• messenger RNA (mRNA) - long RNA strands transcribed from DNA
• reads genetic messages in DNA and produces the proteins that the DNA asks for

central dogma - aka gene expression; info passes DNA > RNA > proteins 

• transcription - transfer of info from DNA to RNA
  • produces mRNA
  • starts when RNA polymerase binds to promoter binding site
  • creates complementary transcript (uracil in place of thymine)
• translation - transfer of info from RNA to protein
  • directs sequence of amino acids
  • each group of 3 nucleotides codes for an amino acid
  • rRNA reads the mRNA to make the polypeptide chain

genetic code - consists of codons (blocks of information) 

• same in almost all organisms
  • supports belief that all organisms have the same root
  • mitochondria/chloroplasts read code differently
• each codon corresponds to a specific amino acid
• 3-nucleotide sequence in each codon (triplet code)
• reading frame - part of genetic code being read by mRNA
• removing a single nucleotide or 2 would mess everything up
• triplet binding assay - developed by Nirenberg/Leder to see which radioactive amino acid the triplet binded to; tested all 64 possible combinations
• mRNA can be transferred from 1 organism to another and still work