1 / 18

Transmission of Information

REPLICATION. DNA. DNA. TRANSCRIPTION. mRNA. TRANSLATION. amino acids. protein !. Transmission of Information. SUMMARY. http://www.youtube.com/watch?v=NJxobgkPEAo http://www.youtube.com/watch?v=D5vH4Q_tAkY http://www.youtube.com/watch?v=d1UPf7lXeO8

lee-chan
Download Presentation

Transmission of Information

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. REPLICATION DNA DNA TRANSCRIPTION mRNA TRANSLATION amino acids protein ! Transmission of Information • SUMMARY

  2. http://www.youtube.com/watch?v=NJxobgkPEAo • http://www.youtube.com/watch?v=D5vH4Q_tAkY • http://www.youtube.com/watch?v=d1UPf7lXeO8 • http://www.youtube.com/watch?v=B6O6uRb1D38 • http://www.youtube.com/watch?v=yJdAxuIA6QM • http://www.youtube.com/watch?v=u9dhO0iCLww

  3. Transcription • Copies the DNA code to mRNA • DNA unwinds • Only 1 strand is transcribed • Complimentary base pairing of nucleotides C-G G-C T-A A-U • This pairing forms the mRNA • RNA polymerase helps form the new mRNA • initiation signal - “start here” • termination sequence - “stop synthesis”

  4. Transcription Termination sequence mRNA 3’ mRNA 5’

  5. Translation • Translation occurs on the ribosomes • Ribosome spheres dissociate into 2 parts • Each “half” of ribosome is made of... • rRNA • polypetides (enzymes) • 60S unit (larger piece of ribosome) • 40S unit (smaller piece of ribosome)

  6. Translation • Translation occurs on the ribosomes • mRNA is “stretched out” on ribosome • Nucleotides on the mRNA are grouped into 3s to form: “CODONS” • each CODON carries a 3 letter code to translate into an amino acid • “Anticodons” on tRNA will match-up with the codons

  7. 60 S mRNA codons UUG AUG GCU AUG 3’ 5’ Ribosome rRNA rRNA 40 S AUG – School Starts in August

  8. Genetic Code • The Genetic Code • Broken in 1961 by Marshall Nirenberg and coworkers • Made poly-U mRNA and “fed” it to ribosomes • The only peptide made was phenylalanine • Therefore, UUU codes for Phe • Each AA is coded for by a sequence of 3 nucleotides on mRNA = CODON

  9. Translation • 4 STAGES in Protein Synthesis: • Activation • Initiation • Elongation • Termination

  10. activated AA fMET anticodon C A G Activation • Each AA is activated by reacting with an ATP • The activated AA is then attached to particular tRNA... (with the correct anticodon)

  11. Elongation • The new peptide is added on and the whole ribosome “translocates” or moves down one codon. • A new “A site” is available for another AA to add.

  12. Termination • After the last translocation (the last codon is a STOP), no more AA are added. • “Releasing factors” cleave the last AA from the tRNA • The polypeptide is complete

More Related