1. Gene Action: From DNA to Protein Transcription: making a mRNA from 1 side of DNA (acts as a template) Translation: production of a protein by aligning and joining mRNA and tRNA Translation into protein Replication of DNA Transcription of mRNA

2. Ribonucleic Acid (RNA): Single-stranded Sugar: ribose Contains uracil (not thymine) Transcription: Jacob and Monod (1961): Set of genes called operon which switch on transcription process

3. Transcription factors (group of proteins) + RNA polymerase unwind DNA RNA nucleotides bond with exposed complementary bases on the DNA template strand mRNA short-lived; 500 to 4500 bases long (3 bases = codon for a specific amino acid)

4. Translation Occurs at the ribosomes Anticodon of tRNA joins with AUG codon of mRNA (rRNA helps) Amino acid pops off end of tRNA Amino acids string together to form a protein (Protein Synthesis) AUG (Initiator Codon) UGA, UAA, UAG (Terminator Codons) tRNA: cloverleaf shape (75-80 nucleotides long); smallest rRNA: acts as a ribozyme (catalyzes formation of peptide bonds between amino acids); 100-3000 nucleotides; 80% of all RNA in the cell

5. Codons 3 letters (nucleotides) = 1 amino acid 4 3 = 64 possible triplets Code: unambiguous – Each triplet is specific for only a single amino acid Code: degenerate – An amino acid can have more than 1 codon Wobble Hypothesis: (Crick) 3 rd base in the triplet is most flexible to allow it to recognize more than 1 base in the codon of mRNA Valine:GUU GUC GUA GUG Introns: base sequences within a gene that are copied and then removed before a protein can be made Exons: the DNA sequences of a gen that code for an amino acid

6. Universality of the genetic code all life evolved from a common ancestor Proteins: fold into 3D shape (to be active and functional) 1 0 Structure: amino acid sequence of a polypeptide chain 2 0 Structure: coils, loops, helices 3 0 Structure: large; attract or repel H 2 O 4 0 Structure: more than 1 polypeptide chain Misfolded proteins in Alzheimer Disease, Lou Gehrig’s Disease (ALS), Parkinson Disease