RNA Structure and Function How Genes Work AP

RNA Structure and Function How Genes Work AP Biology

What do genes code for? n How does DNA code for cells & bodies? u how are cells and bodies made from the instructions in DNA AP Biology proteins cells bodies

The “Central Dogma” n Flow of genetic information in a cell u How do we move information from DNA to proteins? DNA tran replication AP Biology n io t p i r sc RNA tr on i t a l ans protein DNA gets all the glory, but proteins do all the work! trait

a a From gene to protein nucleus DNA cytoplasm transcription m. RNA a a translation a a a protein a a a a ribosome trait AP Biology

Transcription from DNA nucleic acid language to RNA nucleic acid language AP Biology 2007 -2008

RNA n n ribose sugar N-bases uracil instead of thymine u. U : A u. C : G u n n single stranded lots of RNAs u DNA AP Biology m. RNA, t. RNA, r. RNA, si. RNA… transcription RNA

Transcription n Making m. RNA u u transcribed DNA strand = template strand untranscribed DNA strand = coding strand n u same sequence as RNA enzyme n RNA polymerase coding strand 5 C DNA G 3 AP Biology build RNA 5 3 A G T A T C T A rewinding m. RNA 5 G C A T C G T T A 3 G C A U C G T A G C A T RNA polymerase C A G C T G A T unwinding 3 5 template strand

Matching bases of DNA & RNA n Match RNA bases to DNA bases on one of the DNA strands G C U A G G U U C A AG A C G A U A C 5' RNA A C C polymerase G A U 3' T G G T A C A G C T A G T C A T CG T A C CG T AP Biology U C

Translation from nucleic acid language to amino acid language AP Biology 2007 -2008

How does m. RNA code for proteins? DNA TACGCACATTTACGCGG m. RNA AUGCGUGUAAAUGCGCC 4 ATCG 4 AUCG protein ? Met Arg Val Asn Ala Cys Ala 20 AP Biology How can you code for 20 amino acids with only 4 nucleotide bases (A, U, G, C)?

m. RNA codes for proteins in triplets DNA TACGCACATTTACGCGG codon m. RNA AUGCGUGUAAAUGCGCC ? protein AP Biology Met Arg Val Asn Ala Cys Ala

The code n Code for ALL life! strongest support for a common origin for all life u n Code is redundant several codons for each amino acid u Why is the wobble good? n Start codon u u n AP Biology AUG methionine Stop codons u UGA, UAG

How are the codons matched to amino acids? DNA m. RNA 3 5 5 3 TACGCACATTTACGCGG AUGCGUGUAAAUGCGCC 3 t. RNA amino acid AP Biology UAC Met codon 5 GCA Arg CAU Val anti-codon

Transfer RNA structure n “Clover leaf” structure anticodon on “clover leaf” end u amino acid attached on 3 end u AP Biology

Ribosomes n Facilitate coupling of t. RNA anticodon to m. RNA codon u n organelle or enzyme? Structure ribosomal RNA (r. RNA) & proteins u 2 subunits u large n small n AP Biology E P A

Building a polypeptide n Initiation brings together m. RNA, ribosome subunits, initiator t. RNA u n Elongation adding amino acids based on codon sequence u n Termination 3 2 1 end codon u Val Leu Met Met Leu Ala Leu release factor Ser Trp A C t. RNA G U AC 5' CUGAA U m. RNA A U G 3' E P A AP Biology 5' U A C G A C AA U G CU G 5' 3' U A C GA C A U G C UG AAU 3' 5' U A C G A C AA U AU G C U G 3' A CC U GG U A A 3'

Bacterial chromosome Protein Synthesis in Prokaryotes Transcription m. RNA Psssst… no nucleus! Cell membrane Cell wall AP Biology 2007 -2008

Translation in Prokaryotes n Transcription & translation are simultaneous in bacteria DNA is in cytoplasm u no m. RNA editing u ribosomes read m. RNA as it is being transcribed u AP Biology

Any Questions? ? What color would a smurf turn if he held his breath? AP Biology 2007 -2008

Substitute Slides for Student Print version AP Biology 2007 -2008

Can you tell the story? AP Biology

The Transcriptional unit enhancer 1000+b 3' exons 20 -30 b RNA TATA polymerase TAC transcriptional unit 5' DNA ACT introns 5' 3' 5' AP Biology 3'