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Snurps? describe how cells modify RNA after transcription.

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Presentation on theme: "Snurps? describe how cells modify RNA after transcription."— Presentation transcript:

1 Snurps? describe how cells modify RNA after transcription

2 Promoter DNA sequence where RNA polymerase initiates transcription describe how cells modify RNA after transcription

3 Trasnscription Transcription factors + RNA polymerase2 = Transcription initiation complex describe how cells modify RNA after transcription

4 Why is it called the TATA BOX? describe how cells modify RNA after transcription

5 Termination Transcription occurs until Polymerase II reaches polyadenylation signal (AAUAAA) describe how cells modify RNA after transcription

6 RNA processing 5’Cap and poly-A-tail Pre mRNA describe how cells modify RNA after transcription

7 Predict what needs to happen to this molecule. Average length of transcription is 27,000 base pairs. Average protein coded by 1,200 bp.

8 Splicing describe how cells modify RNA after transcription

9 Introns Cut out of the pre- mRNA Will be used later describe how cells modify RNA after transcription

10 Exons “exit nucleus” as finished mRNA describe how cells modify RNA after transcription

11 What do snRNPs do? describe how cells modify RNA after transcription

12 snurps Recognize splice sites RNA and protein molecules snRNPs join with eachother to build Spliceosome describe how cells modify RNA after transcription

13 What properties allow RNA to function as enzymes? describe how cells modify RNA after transcription

14 What properties allow RNA to function as enzymes? Single stranded Bases match up with each other Some bases contain functional groups that may participate in catalysis Hydrogen bonding adds to specificty to its catalytic ability describe how cells modify RNA after transcription

15 Ribozymes Introns become self splicing ribozymes

16 What are Ribosomes?

17 Ribosomes rRNA Transcribed from DNA  rRNA 3 molecules (bacteria) 4 molecules (eukaryotes) 2 sub Units Describe how RNA is translated into proteins

18 Psite- holds tRNA Asite- holds next tRNA holding next amino acid Esite- exiting tRNA Describe how RNA is translated into proteins

19 Fig. 17-17 3 3 5 5 U U A A C G Met GTP GDP Initiator tRNA mRNA 5 3 Start codon mRNA binding site Small ribosomal subunit 5 P site Translation initiation complex 3 EA Met Large ribosomal subunit

20 Video 1

21 Video 2

22 Fig. 17-18-1 Amino end of polypeptide mRNA 5 3 E P site A site

23 Fig. 17-18-2 Amino end of polypeptide mRNA 5 3 E P site A site GTP GDP E P A

24 Fig. 17-18-3 Amino end of polypeptide mRNA 5 3 E P site A site GTP GDP E P A E PA

25 Fig. 17-18-4 Amino end of polypeptide mRNA 5 3 E P site A site GTP GDP E P A E PA GTP Ribosome ready for next aminoacyl tRNA E P A

26 Predict which end of the mRNA moves through the ribosome first. Describe how RNA is translated into proteins

27 Poly Ribosomes Why? Describe how RNA is translated into proteins

28 Where does polypeptide synthesis always begin? Describe how RNA is translated into proteins

29 Where does polypeptide synthesis end? Option 1: cytosol Option 2: Endoplasmic reticulum (marked by signal peptide) Describe how RNA is translated into proteins

30 The ribosome recognizes these molecules at a complex called signal-recognizing particle (SRP)

31

32 Write your summary and Q’s


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