1. DNA • Structure • Replication • Functions (Stores and provides copies of genetic material- genes) • Blueprint (genes) for Protein Synthesis (Enzymes and cell building blocks)

2. Francis Crick

4. RNA (Ribonucleic Acid) • Why do we need RNA? • Why can’t DNA directly make proteins? • Where is DNA located? Can it leave? Why does it stay there? • Where are proteins made? • Temporary copies of parts of the blueprint

5. Ribonucleic acid (RNA) • carries DNA’s instructions • acts as an link between DNA in the nucleus and protein synthesis in the cytoplasm. • plays several different roles in protein synthesis.

6. Similarities DNA and RNA • Both are nucleic acids • Both are made up of nucleotides (sugar, base, phosphate)

7. DNA versus RNA

8. DNA versus RNA

9. Differences between DNA and RNA DNA RNA

10. Genes expression is through protein synthesis

11. Types of RNA 1. Messenger RNA (mRNA) -formed in nucleus from DNA template -Carries copies of instructions for protein synthesis to the ribosomes in cytoplasm (nuclear membrane pores) 2. Ribosomal RNA (rRNA) -along with some proteins make up ribosomes (cytoplasm) 3. Transfer RNA (tRNA) - transport amino acids to ribosomes (cytoplasm) All types of RNA are formed in the nucleus.

12. Transfer RNA

13. Transcription • Messenger RNA (mRNA) is made from DNA • DNA is template • Complementary RNA is produced • Nucleus (eukaryotic cells) • RNA polymerase (unwinds the DNA and adds nucleotides to form RNA) • Uracil is paired with adenine

14. Transcription steps • RNA polymerase binds to promoter (“start”) region of gene • RNA polymerase unwinds and separates the two strands of DNA • RNA polymerase adds complementary RNA nucleotides • RNA polymerase reaches a sequence of nucleotides on the gene that signals “stop” • RNA polymerase detaches

15. Transcription

16. TranscriptionTemplate versus Nonsense Strand

17. http://www.fed.cuhk.edu.hk/~johnson/teaching/genetics/animations/transcription.htmhttp://www.fed.cuhk.edu.hk/~johnson/teaching/genetics/animations/transcription.htm • What does this remind you of? • Practice creating complementary mRNA

18. Post-transcription • Pre-mRNA molecule produced and undergoes processing and editing. (spliceosomes) • Introns – cut out and discarded • Exons – remaining pieces spliced back together to form mRNA • mRNA travels through nuclear membrane pore into cytoplasm