1. LEQ: How does RNA help to make a protein? 10.6 to 10.9

2. The Central Dogma of Biology

3. The Central Dogma of Biology • Transcription – DNA making RNA • Translation – RNA making Protein; (aka protein synthesis)

4. The Central Dogma of Biology • Archibald Garrod (1909) – determined that genes dictate phenotype through enzymes • His ideas stem from his observations of an inherited disease – Alkaptonuria where affected individuals have a defective enzyme that does not break down two amino acids as aresult the produce Alkapton which makes their urine to turn black

5. The Central Dogma of Biology • George Beadle and Edward Tatum (1940’s) – American geneticists working with bread mold (Neurasporacrassa) • Strains of nutritional mutants helped them prove that specific enzymes were need to at specific steps in metabolic pathways • “One Gene/One Enzyme”

6. Transcription • DNA making RNA • Takes place in the nucleus • One main enzyme – RNA Polymerase • RNA is transcribed in a 5’ to 3’ direction • Only ONE strand of DNA is transcribed at a time

7. DNA language is rewritten in the process of Transcription

8. Nucleic acid language is converted to the language of proteins in the process of Translation

9. Transcription Initiation – DNA separates and ONE strand serves as a template for the RNA; RNA polymerase binds to the promotor region of DNA

10. Transcription Elongation -RNA elongates as complementary RNA nucleotides match up with DNA nucleotides are added in a 5’ to 3’ direction; U is substituted for T As RNA polymerase moves forward, RNA releases from DNA; and DNA rewinds

11. Transcription Termination – RNA polymerase reaches the terminator sequence & releases the DNA and RNA; DNA rewinds; RNA is ready for the next step

12. Transcription • Promoter – specific nucleotide sequence in DNA, located @ the start of a gene; binding site for RNA polymerase; where transcription begins • Transcription region – segment of DNA that is made into RNA; the gene • Terminator – sequence of nucleotides in DNA that marks the end of a gene. It signals • Sense Strand – the strand of DNA that is transcribed into DNA • Nonsense Strand – the strand of DNA this in not transcribed

13. The Rosetta Stone of Life

14. Genetic Code • Universal – shared by all organisms; the set of rules giving the correspondence between nucleotide triplets (codons) and amino acids in proteins • Codes for Amino acids – • Building blocks of a proteins • 20 different amino acids • Coded for by groups of three nucleotide bases - codons

15. Codons • Codons – groups of three consecutive nucletides in mRNA that specifies a particular amino acid or a polypeptide termination signal • AUG – start codon; indicates the starting point for translation; also codes for methionine • Stop codons – don’t code for an amino acid instead it signals the end of translation