Ch 9 Expressing Genetic Information

1. 1 Ch 9 Expressing Genetic Information Once you have a gene, then what? How does a sequence of nucleotides carry information?

2. Know Fig. 1.35 on P. 47 3 4 2 The Central Dogma9 S Phase Transcription Translation Cell Functions Structure Function Transport Etc. ... (See 9.2) 5

3. Protein Examples17 • Membrane Transport Channels • Tubulin (microtubules) • ATP Synthetase • RuBisCo • Hemoglobin • Cyclin • Keratin (fingernails and hair) E. coli ATP Synthetase

4. Base sequence acts like letters of the alphabet spelling words and sentences Base pairing: One half of DNA can be used to copy more. 2 Main Steps 1. Transcription: Using DNA (gene) as a template to make mRNA molecules. Ribosome = Protein + rRNA 80% of RNA in the body is rRNA 2. Translation:Using tRNA to match amino acids to the mRNA pattern and synthesize a functional protein. Nucleus DNA Transcription RNA Translation Protein Cytoplasm How do Nucleic Acids Carry Information? Gene = Fundamental physical unit of heredity; Section of DNA that codes for a specific polypeptide product

5. Protein Synthesis Overview10 One Gene  One Polypeptide

6. Remember… It is the side chains that make one amino acid different from another! So, differences in amino acid order changes the shape and function of the protein. 4

7. Remember also about RNA…4 • It is a nucleic acid • It is made up of nucleotides • The nucleotides contain ribose, phosphate, and a nitrogenous base (A,U,C,G) • It is single stranded

8. Loop 3 Loop 1 Loop 2 9 The 3 Faces of RNA All are transcribed from DNA with complementary sequences to DNA (Base paired) tRNA:Transfer RNA Cross shaped molecule that brings specific amino acids to ribosomes in correct order to add to polypeptide chain mRNA: Messenger RNA Dictates amino acid sequence at ribosome during protein synthesis rRNA: Ribosomal RNA Combines with proteins to form ribosomes which synthesize polypeptides

9. P. 241 in your text!

10. Quick Quiz… For the following DNA template sequences, write the complementary RNA sequences from 5’ – 3’. Don’t forget antiparallel structure • 5’ – ATGCCG – 3’ • 5’ – CCGTTA – 3’ • 3’ – GTA – 5’ • CGGCAU • UAACGG • CAU

11. Know start and stop codons! Table on P. 237 Quick Quiz: What’s the DNA sequence for Methionine (5’-3’) What’s wrong with the answer TAC? CAT 6

12. Cracking the Genetic Code6 Each 3 letter codon is a word… Marshall Nirenbergshared the Nobel Prize in 1968 for helping to crack the genetic code. 8 7 Think about naming one amino acid. How many different words are possible? 9

13. How many words are possible? ____ _____ _____ A base goes in each space 4 x 4 x 4 = 64 Maximum 64 words in our system… But we only have 20 or so amino acids. Like English, some words are synonyms. How many codons could you make if each codon is 4 bases long? 4 x 4 x 4 x 4 = 256

14. Also need initiation factors to start… In the Nucleolus… Transcription – the synthesis of mRNA 10 Different RNA Polymerase for each kind of RNA!

15. 1. Add mG cap (methyl Guanine) – helps ribosome attach to the beginning of the mRNA for translation 2. Add Poly-A Tail ~ 100-200 adenines Both protect the mRNA from enzyme degradation 3. Splicing out introns to leave only exons. Requires special enzymes that know where/how to cut. Introns = “In-between” – doesn’t code for part of the protein RNA Processing10 See p. 245 in your text mRNA has a very short life span… Enzymes continually decompose it.

16. tRNA ~ the Amino Acid Adapter10 Primary transcript has bases modified and is folded into the right cross shape

17. tRNA Charging10 • Requires ATP • Attaches the RIGHT amino acid to the tRNA • - Makes sure the amino acid matches the anti-codon on the tRNA

18. Initiation of Translation10 See P. 249

19. Translation Elongation10 See P. 250

20. Termination of Translation10 Stop codons don’t match any amino acid charged tRNA, so a release factor protein is bound instead.

21. Polyribosomes10 More than one ribosome can hook onto any one mRNA, greatly speeding translation!

22. 1 Transcription Nucleus RNA transcript DNA 2 Intron RNA processing Amino acid CAP Tail mRNA Intron Enzyme tRNA 3 Amino acid attachment Ribosomal subunits 4 Initiation of translation Stop codon Anticodon Codon 6 Termination 5 Elongation Hana hou…10

23. Protein Modification 11 Chaperone Protein Different proteins may help stabilize the polypeptide as it folds or cut it into appropriate pieces. Eg. Pepsin

24. Reading Frame Initiation determines where translation starts… After that, just count by 3s… Frame 1 A A U G C G G A C U A A Asparagine Alanine Aspartate Stop Frame 2 A A U G C G G A C U A A Methionine Arginine Threonine Frame 3 A A U G C G G A C U A A Can you find the amino acid sequence for frame 3? Cysteine-glycine-leucine

25. Translation Errors12 Use the genetic code on p. 237 Any change in “reading frame” or mistakes in DNA or mRNA sequence can change the amino acid sequence, making a different protein!

26. Viruses10 Virus = RNA/DNA + Protein Coat + (A Few Enzymes) Can’t reproduce on their own Are they alive?!? Viruses can cause— Bacteria to die HIV/AIDS Colds Flu Etc.

27. 10

28. Virus Life Cycle Retroviruses have RNA instead and use “reverse transcriptase” to turn their RNA into DNA before step 1. Eg. HIV 10

29. Lysogenic vs. Lytic Infection10 Can camouflage with part of the cell membrane

30. Gene Therapy Theory 14 Ebola Reston Ebola Zaire 15 13 Viruses in Life 16 Influenza A 31,710x 16 HIV 14,555x 16 Herpes simplex 25,120x

31. Sources Cited 1. www.lbl.gov/enews/ 2-15-02.html 2. library.thinkquest.org/3659/ orgchem/nucleicacids.html 3. tRNA: niko.unl.edu/bs101/notes/ lecture10_1.html 4. http://gened.emc.maricopa.edu/bio/bio181/BIOBK/BioBookTOC.html 5. Epithelial Cell: www.durr.demon.co.uk/ algae%20&%20protozoa%202.html 6. www.accessexcellence.org/ AB/GG/genetic.html 7. www.zum.de/Faecher/Materialien/ beck/13/bs13-5.htm 8. http://www.nobel.se/medicine/laureates/1968/ 9. http://www.emc.maricopa.edu/faculty/farabee/BIOBK/BioBookPROTSYn.html 10. BioCD. From Biology, Fifth Edition. Campbell, Reece, Mitchell. Addison, Wesley, Longman. 1999. 11. http://cwx.prenhall.com/horton/medialib/media_portfolio/text_images/FG04_33.JPG 12. www.orst.edu/instruction/bb331/ lecture02/Figframeshift.html 13. http://www.cnn.com/HEALTH/9604/16/nfm/ebola.levine/ebola.reston.large.jpg 14. www.virology.net/Big_Virology/ BVRNAfilo.html 15. www.accessexcellence.org/AB/WYW/ wkbooks/PAP/therapy.html 16. www.denniskunkel.com with permission 17. http://www.nature.com/nsmb/journal/v11/n2/fig_tab/nsmb0204-110_F1.html

32. Cookbook http://www.cookbookswelove.com/images_cookbooks/cooksillustrated_thenewbestrecipe_475h.jpg www.biologycorner.com/ images.php http://www.simonsays.com/assets/isbn/0684818701/C_0684818701.gif

33. Cookbook: DNA I am the source of the master knowledge of chefs over the years. Though I cannot leave the pantry, all cooking wisdom comes from me. What am I? Answer: I am DNA, the famous double helix, the source of all the information required to build cell proteins and structure.

34. The Copyist

35. The Copyist: RNA Polymerase I copy the recipes from the master cookbook to distribute to the kitchen for the cooks to make. What am I? Answer: I am RNA Polymerase, the enzyme that unzips DNA to make an mRNA copy of the gene.

36. The Recipe Card http://www.frugalcooking.com/printables/recipecards/cardswrecipe/pumpkinroll.gif http://www.biologycorner.com/resources/mRNA-colored.gif

37. The Recipe Card: mRNA I am a transcribed copy of the recipe from the master cookbook. I am directions followed by the chef to create the food. What am I in the cell? Answer: I am mRNA – transcribed from DNA to provide the working copy of the gene. I will provide instructions to the ribosomes to bind amino acids together in the right order.

38. The Chef http://www2.wb.psu.edu/content/cafe/images/chef.gif http://fig.cox.miami.edu/~cmallery/150/cells/ribosome.jpg

39. The Chef: A Ribosome I am the heart of the kitchen. Using a recipe card and ingredients, I prepare ono food. What am I? Answer: I am a ribosome. Made of protein and rRNA, I take the information in mRNA and use it to translate the mRNA message into an amino acid sequence that will become a protein.

40. The Faulty Recipe http://www.frugalcooking.com/printables/recipecards/cardswrecipe/pumpkinroll.gif http://www.monografias.com/trabajos5/virus/Image164.gif

41. The Faulty Recipe: Viral RNA I am a suspicious looking recipe that if cooked would create poisonous food. What am I? Answer: I am viral or other intruder RNA which would make the ribosome create proteins that are bad for the cell, and eventually more viruses to infect other cells.

42. The Food Service Inspector http://photos1.blogger.com/blogger/6132/611/200/policeman-cartoon.jpg http://www.cshl.edu/public/releases/images/model-schematic.gif

43. The Food Service Inspector: RNAi Molecule I patrol the kitchen, looking for suspicious recipes and tearing them up before they can be made into poisonous food. What am I? Answer: I am the RNAi molecule, a complex of enzymes and RNA which allow me to identify dangerous RNA and destroy it.

44. Ingredients for Food http://www.yfc.org/columns/devos.php?DevoID=291

45. Ingredients for Food: Amino Acids I am the critical ingredients required for producing the recipes for ono food. Without me, there would be no food made. What am I? Answer: I am amino acids, waiting to form peptide bonds with the help of a ribosome.

46. Bread, Pancakes, Biscuits, Muffins http://www.bavarianinn.com/bi/home.nsf/LookupFiles/breads.gif/$file/breads.gif

47. Food: Cellular Proteins I am the end product of this complex process. Bread, pancakes, biscuits, or muffins – from the same basic starting ingredients, come different yummy things to nourish the body. What am I? Answer: I am the many cellular proteins that are required to make a cell function. Enzymes, hemoglobin, keratin in your hair, ATP Synthetase, and pepsinogen are just a few examples. Cells would not exist without me.

48. Nucleus www.cdli.ca/~dpower/ cell/nucleus.htm