1 / 17

Topic 7 Cont’d

Topic 7 Cont’d. Transcription and Translation. Transcription Basics. DNA vs. RNA. Transcription Basics cont’d. Directionality: read 3’-5’; made 5’-3’ Promoter & TATA boxes Nucleoside triphosphates Contains the sense strand and antisense strand

stacy-trujillo
Download Presentation

Topic 7 Cont’d

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. Topic 7 Cont’d Transcription and Translation

  2. Transcription Basics • DNA vs. RNA

  3. Transcription Basics cont’d • Directionality: read 3’-5’; made 5’-3’ • Promoter & TATA boxes • Nucleoside triphosphates • Contains the sense strand and antisense strand • Sense strand = always 5’-3’ and is the same as the mRNA that is produced except T for U • Antisense strand = always 3’-5’ and is the strand that forms the template and is transcribed.

  4. Animation sites • http://www.stolaf.edu/people/giannini/flashanimat/molgenetics/transcription.swf • http://vcell.ndsu.nodak.edu/animations/transcription/first.htm

  5. Translation The process of polypeptide/protein production using mRNA as a guide Requires: mRNA transcript tRNA tRNA activating enzymes ribosomes genetic code…..

  6. The Genetic COde

  7. The Genetic Code cont’d • It’s a triplet code (codon) = 3 bases code for 1 amino acid • There are 64 different codons • Duplication = degeneracy = possible for 2 or more codons to code for the same amino acid • Code is essential universal (find me 2 exceptions by next class for 1 point e.c. each)

  8. Amino Acids

  9. tRNA • All tRNAs have base-paired ds sections that become loops • Triplet bases complementary to mRNA codons…called anticodons • A 3’-5’ CCA terminal end for amino acid attachment • The above permit 3 distinct binding attachment of the tRNA to the ribosome

  10. tRNA cont’d

  11. tRNA a S = F example • The base sequence of tRNa molecules vary = some variable features in its structure • An extra small loop is sometimes present • The bp sections are sometimes helical • Results in: • A distinctive 3-d shape • Distinctive chemical properties • ALLOWS THE CORRECT AA TO BE ATTACHED TO THE 3’ END BY A tRNA ACTIVATING ENZYME (aminoacyl-tRNA sythetase) • There are 20 different tRNA activating enzymes – one for each of the 20 diff. AA

  12. Ribosome Basics • Composed of protein and rRNA • Consist of 2 subunits (small and large) • Possess 3 binding sites for tRNA (2 tRNAs can bind at the same time) • Possess a binding site for mRNA • Free vs. Bound (RER) • 80S in Euks vs. 70S in Proks & Euk. organelles

  13. Ribosome (2 site version)

  14. Translation Step 1 - Initiation

  15. Polysomes & Movie Time • http://vcell.ndsu.nodak.edu/animations/translation/movie.htm

More Related