1. RNA and Protein Synthesis

2. Central Dogma (idea) DNA  RNA  Proteins
Replication Transcription Translation  Protein Synthesis
Proteins are used to build cells and do much of the work inside cells

3. The Structure of RNA RNA, like DNA, is made up of nucleotides
However, there are 3 differences between DNA and RNA:
RNA has Ribose instead of Deoxyribose
RNA has Uracil instead of Thymine
RNA is Single-stranded instead of Double-stranded

4. 3 Types of RNA
Messenger RNA (mRNA) – carries the message from the DNA to the ribosomes
Ribosomal RNA (rRNA) – make up part of the structure of a ribosome
Transfer RNA (tRNA) – transfers amino acids to the ribosomes

5. Protein Synthesis

6. Transcription Making RNA from DNA (in the nucleus)
DNA helicase unzips the DNA stand
RNA polymerase binds to a special region of DNA called a promoter
The RNA polymerase then attaches to the DNA strands and uses it as a template to build the mRNA
A will now pair with U, T still pairs with A
C and G still pair with each other

7. Transcription

8. Practice Transcription…
DNA – AGC-TCC-GAT-GCA-TAC-TTG
RNA – UCG-AGG-CUA-CGU-AUG-AAC
DNA – GCC-AGT-GCT-TAC-GAA-CTG
RNA – CGG-UCA-CGA-AUG-CUU-GAC

9. RNA Editing
RNA requires a little editing before it is ready to go to the ribosome to make proteins
Introns – sections of RNA that do not code for a protein (“in the way”)
Cut out
Exons – sections of RNA that do code for a protein (“expressed”)
spliced back together

10. RNA Editing

11. Translation

12. Translation Making the proteins from the mRNA (“translating the code”)
Occurs on the ribosomes

13. Translation
mRNA must be transcribed from the DNA in the nucleus and released into the cytoplasm
The mRNA attaches to the ribosome
Start Codon is AUG (this tells the ribosome where to start translation) ADD TO YOUR NOTES
The tRNA brings the proper amino acid to the ribosome
Anticodon – sequence of bases on the tRNA that pair with the mRNA

14. Translation The amino acids form a peptide bond to hold them together
The next amino acid is brought in and is attached
This continues until the ribosome reaches a stop codon
The completed protein is then released

15. Translation

16. The Genetic Code Proteins are made of amino acids
There are 20 different amino acids
A codon is a 3 base sequence that codes for a specific amino acid
There are 64 possible codons

17. The Genetic Code

18. Another way to read the codons

19. The Genetic Code mRNA sequence:
UCGCACGGU
Separate into codons (groups of 3 bases):
UCG-CAC-GGU
Identify the amino acids:
Serine-Histidine-Glycine

20. Mutations

21. Mutations Changes in the DNA sequence that affect genetic information
Gene mutations – result from changes in a single gene
Chromosomal mutations – involve changes in whole chromosomes

22. Gene Mutations
Frameshift or Point mutations – a mutation that occurs at a single point (only 1 nucleotide is changed)
Substitution – a single nucleotide is substituted for another one (A instead of G)
Insertion – a single nucleotide is added
Deletion – a single nucleotide is removed

23. Gene Mutations
Insertions and deletions cause frameshift mutations because they shift the “reading frame” of the genetic message.

28. Chromosomal Mutations
Deletion – a section of a chromosome is deleted
Duplication – a section of a chromosome is copied and inserted
Inversion – a section of a chromosome is moved from one spot to another
Translocation – a piece of a chromosome is moved from one chromosome to another

29. Chromosomal Mutations