From Genes to Proteins

1. From Genes to Proteins

2. RNA Single-stranded Ribose (sugar) Uracil (base)  bonds to Adenine DNA Double-stranded Deoxiribose (sugar) Thymine (base)  bonds to Adenine DNA and RNA differ in 3 ways

3. The Flow of Information

4. The Flow of Information

5. Transcription • This is the first step in Protein Synthesis: 1. The instructions are transferred (“transcribed”) to an RNA molecule.

6. To sum up Transcription… • Info transferred from DNA to RNA • What is the Enzyme involved in Transcription? • Answer  RNA Polymerase

7. Transcription has 3 steps… 1 – RNA Polymerase binds to the gene’s promoter(DNA) (like a starting line in a race).

8. 2 – RNA Polymerase UNWINDS the DNA molecule. The DNA nucleotides are exposed.

9. 3 – RNA Polymerase (yeah, that same enzyme again…) adds complimentary nucleotides to separated DNA strand. ** Remember  RNA has Uracil instead of Thymine for a base.

10. The RNA Polymerase will continue transcription until it reaches the “stop signal” on the DNA molecule (like a finish line). • Then the RNA strand is released and goes on to the next step…Translation

11. Transcription

12. Transcription

13. 3 types of RNA • mRNA (messenger RNA) • rRNA (ribosomal RNA) • tRNA (transfer RNA)

14. Messenger RNA • Delivers information to the site of Translation.

15. mRNA instructions are written in “3-nucleotide” sequences. • These sequences are called codons. • Ex. See pg. 209 • UUU, CUG, ACU, etc. • There are 64 possible codons.

16. Translation • Remember what happens in Transcription? • DNA to RNA • In Translation…RNA is coded for Amino Acids.

17. Translation takes place in the Cytoplasm. • tRNA (Transfer RNA) molecules carry single amino acids. • They also have an OPPOSITE “3-nucleotide” sequence called anticodons.

18. rRNA (Ribosomal RNA) molecules are like assembly lines  they carry: • 1 mRNA • 2 tRNA

20. 7 Steps in Translation 1 – mRNA start codonstarts the process at the P site. 2 – the next tRNA bonds to the next codon at the A site. 3 – A & P are holding 2 tRNA’s…a peptide bond is formed between 2 amino acids.

21. 4 – tRNA detaches from P-site, leaves behind amino acid, leaves Ribosome. 5 – tRNA at A-site moves to the P-site. Now a new codon is ready at the A-site for another tRNA.

22. 6 – tRNA detaches from P-site, leaves behind amino acid, leaves ribosome. 7 – (Steps 2 – 6 repeat until a stop codon is reached). Ex. UAG, UAA, UGA. • A new protein is then released into the cell.

23. Translation

24. Translation