1. 1copyright cmassengale

2. RNA 2

3. 3 Roles of RNA and DNA DNA is the MASTER PLAN RNA is the BLUEPRINT of the Master Plan copyright cmassengale

4. 4 RNA Differs from DNA RNA has a sugar riboseRNA has a sugar ribose DNA has a sugar deoxyribose copyright cmassengale

5. 5 Other Differences RNA contains the base uracil (U)RNA contains the base uracil (U) DNA has thymine (T) RNA molecule is single-strandedRNA molecule is single-stranded DNA is double- stranded DNA copyright cmassengale

6. 6 Remember the Complementary Bases On DNA: A-T C-G On RNA: A-U C-G copyright cmassengale

7. 7 Structure of RNA copyright cmassengale

8. 8. Three Types of RNA Messenger RNA (mRNA) copies DNA’s code & carries the genetic information to the ribosomesMessenger RNA (mRNA) copies DNA’s code & carries the genetic information to the ribosomes Ribosomal RNA (rRNA), along with protein, makes up the ribosomesRibosomal RNA (rRNA), along with protein, makes up the ribosomes Transfer RNA (tRNA) transfers amino acids to the ribosomes where proteins are synthesizedTransfer RNA (tRNA) transfers amino acids to the ribosomes where proteins are synthesized copyright cmassengale

9. 9 Messenger RNA TEMPORARY COPY OF A GENE THAT ENCODES A PROTEIN (CARRIES THE GENETIC MESSAGE FROM DNA) MADE THROUGH TRANSCRIPTION PROVIDES THE PATTERN THAT DETERMINES THE ORDER OF AMINO ACIDS OF A PROTEIN STRAND copyright cmassengale

10. 10 Messenger RNA (mRNA) Carries the information for a specific proteinCarries the information for a specific protein Sequence of 3 bases called codonSequence of 3 bases called codon AUG – methionine or start codonAUG – methionine or start codon UAA, UAG, or UGA – stop codonsUAA, UAG, or UGA – stop codons copyright cmassengale

11. 11 Ribosomal RNA (rRNA) 80% OF THE RNA IN A CELL Made inside the nucleus of a cellMade inside the nucleus of a cell Associates with proteins to form ribosomesAssociates with proteins to form ribosomes Site of protein SynthesisSite of protein Synthesis copyright cmassengale

12. 12 Transfer RNA (tRNA) Clover-leaf shape Single stranded molecule with attachment site at one end for an amino acid, LINKED TOGETHER DURING THE PROCESS OF TRANSLATION Opposite end has three nucleotide bases called the anticodon copyright cmassengale

13. 13 Transfer RNA amino acid attachment site UAC anticodon copyright cmassengale

14. 14 Codons and Anticodons The 3 bases of an anticodon are complementary to the 3 bases of a codon Example: Codon ACU Anticodon UGA UGA ACU copyright cmassengale

15. 15 The Genetic Code A codon designates an amino acid An amino acid may have more than one codon There are 20 amino acids, but 64 possible codons Some codons tell the ribosome to stop translating copyright cmassengale

16. 16 The Genetic Code Use the code by reading from the center to the outside Example: AUG codes for Methionine copyright cmassengale

17. 17 Name the Amino Acids GGG? UCA? CAU? GCA? AAA? copyright cmassengale

18. Transcription and Translation 18copyright cmassengale

19. 19 Pathway to Making a Protein DNAmRNA tRNA (ribosomes) Protein copyright cmassengale

20. 20 Protein Synthesis   The production or synthesis of polypeptide chains (proteins)  Two phases: Transcription & Translation  mRNA must be processed before it leaves the nucleus of eukaryotic cells copyright cmassengale

21. 21

22. 22 DNA  RNA  Protein Nuclear membrane Transcription RNA Processing Translation DNA Pre-mRNA mRNA Ribosome Protein Eukaryotic Cell copyright cmassengale

23. 23 Transcription MAKING mRNA FROM THE GENETIC CODE OF DNA copyright cmassengale

24. 24 Template Strand copyright cmassengale

25. 25 Question:  What would be the complementary RNA strand for the following DNA sequence? DNA 5’--3’ DNA 5’- ATCGGCTAT -3’ copyright cmassengale

26. 26 Answer: DNA: 5’--3’DNA: 5’- ATCGGCTAT -3’ RNA: 3’--5’RNA: 3’- UAGCCGAUA -5’ copyright cmassengale

27. 3 STEPS OF TRANSCRIPTION 1.RNA POLYMERASE UNZIPS THE DNA DOUBLE HELIX (INITIATION) 2.RNA NUCLEOTIDES ARE FORMED FROM THE NUCLEOTIDES IN THE DNA TEMPLATE STRAND (ELONGATION) 3.THE mRNA THAT IS FORMED LEAVES THE NUCLEUS (TERMINATION) copyright cmassengale 27

28. 28 mRNA Processing PIECES OF DNA CALLED INTRONS THAT DO NOT CODE FOR PROTEINS ARE REMOVED LEAVING THE CODING SEGMENTS CALLED EXONS copyright cmassengale

29. 29 CAP Tail New Transcript Result of Transcription copyright cmassengale

30. 30 Translation THE SYNTHESIS OF PROTEINS USING THE CODONS OF mRNA MATCHED WITH THE ANTICODONS OF tRNA Ribosomes read mRNA three bases or 1 codon at a time and construct the proteins copyright cmassengale

31. 31 Transcription Translation copyright cmassengale

32. CHARACTERISTICS DETERMINES THE AMINO ACID SEQUENCE IN A PROTEIN 64 DIFFERENT THREE-BASE CODONS “CODE” FOR 20 DIFFERENT AMINO ACIDS (CARRIED BY tRNA) THERE ARE ALSO START (1) AND STOP (3) CODONS OCCURS AT THE RIBOSOMES REQUIRES ENZYMES AND ENERGY copyright cmassengale 32

33. 33 Step 1- Initiation mRNA transcript start codon AUG attaches to the small ribosomal subunit Small subunit attaches to large ribosomal subunit mRNA transcript copyright cmassengale

34. 34 Ribosomes P Site A Site Large subunit Small subunitmRNA AUGCUACUUCG copyright cmassengale

35. Step 2 - Elongation As ribosome moves, two tRNA with their amino acids move into site A and P of the ribosome Peptide bonds join the amino acids 35copyright cmassengale

36. 36 Initiation mRNA AUGCUACUUCG 2-tRNA G aa2 AU A 1-tRNA UAC aa1 anticodon hydrogen bonds codon copyright cmassengale

37. 37 mRNA AUGCUACUUCG 1-tRNA2-tRNA UACG aa1 aa2 AU A anticodon hydrogen bonds codon peptide bond 3-tRNA GAA aa3 Elongation copyright cmassengale

38. 38 mRNA AUGCUACUUCG 1-tRNA 2-tRNA UAC G aa1 aa2 AU A peptide bond 3-tRNA GAA aa3 Ribosomes move over one codon (leaves) copyright cmassengale

39. 39 mRNA AUGCUACUUCG 2-tRNA G aa1 aa2 AU A peptide bonds 3-tRNA GAA aa3 4-tRNA GCU aa4 ACU copyright cmassengale

40. 40 mRNA AUGCUACUUCG 2-tRNA G aa1 aa2 AU A peptide bonds 3-tRNA GAA aa3 4-tRNA GCU aa4 ACU (leaves) Ribosomes move over one codon copyright cmassengale

41. 41 mRNA GCUACUUCG aa1 aa2 A peptide bonds 3-tRNA GAA aa3 4-tRNA GCU aa4 ACU UGA 5-tRNA aa5 copyright cmassengale

42. 42 mRNA GCUACUUCG aa1 aa2 A peptide bonds 3-tRNA GAA aa3 4-tRNA GCU aa4 ACU UGA 5-tRNA aa5 Ribosomes move over one codon copyright cmassengale

43. 43 mRNA ACAUGU aa1 aa2 U primarystructure of a protein aa3 200-tRNA aa4 UAG aa5 CU aa200 aa199 terminator or stop or stop codon codon Termination copyright cmassengale

44. 44 End Product –The Protein! The end products of protein synthesis is a primary structure of a protein A sequence of amino acid bonded together by peptide bonds aa1 aa2 aa3 aa4 aa5 aa200 aa199 copyright cmassengale

45. 45 Coding process methionineglycineserineisoleucineglycinealanine stop codon protein AUGGGCUCCAUCGGCGCAUAA mRNA start codon Primary structure of a protein aa1 aa2aa3aa4aa5aa6 peptide bonds codon 2codon 3codon 4codon 5codon 6codon 7codon 1 copyright cmassengale