As you come in,

1. As you come in, • Materials: • Karyotyping Activity worksheet • PICK UP Molecular Biology notes packet and Nucleic Acids packet • Plan: • Complete Karyotype Activity (‘til 12:45 pm) • History of DNA notes (12:50 to 1:30 pm) • CrashCourse DNA Intro (1:30 to 1:52 pm) • Homework: • Review notes • Complete Nucleic Acids packet pages 1-2

2. Molecular Biology - DNA History, Structure, Replication, Transcription, and Translation

3. History of DNA

4. Genetic Facts in 1900 • Both female and male organisms have identical chromosomes except for one pair. • Genes are located on chromosomes • All organisms have two types of chromosomes: • Sex chromosomes • Autosomes

5. Male vs. Female Male • Usually the Y chromosome. • Y is usually smaller than the X. • Male genotype: XY • Usually the X chromosome. • X is usually larger than the Y. • Female genotype: XX Female

6. Frederick griffith British bacteriologist 1928 = designed and performed experiment on rats and bacteria that causes pneumonia. 2 strains of the bacteria Type S = causes severe pneumonia Type R = relatively harmless • Because the dead rat tissue showed living Type S bacteria, something “brought the Type S back to life” • Actually one bacterial type incorporated the DNA, or instructions, from the dead bacteria into its own DNA • Known as transformation. Confirmed by Avery, MacLeod, and McCarty in 1944

7. Oswald Avery • Canadian biologist (1877-1955) • Discovered DNA in 1944 with a team of scientists.

8. Hershey and Chase • 1952 • Attempted to solve the debate on whether DNA or proteins are responsible for providing genetic material. • Use a bacteriophage virus (a virus that attacks bacteria) to prove that DNA is definitely the genetic material.

9. The Hershey-Chase Experiment Agitate in a blender to separate phages outside the bacteria from the cells and their contents. Centrifuge the mixture so bacteria form a pellet at the bottom of the test tube. Measure the radioactivity in the pellet and liquid. Mix radioactivelylabeled phages with bacteria. The phages infect the bacterial cells. 1 2 3 4 Radioactiveprotein Emptyprotein shell Radioactivityin liquid Phage Bacterium PhageDNA DNA Batch 1Radioactiveprotein Centrifuge Pellet RadioactiveDNA Batch 2RadioactiveDNA Centrifuge Radioactivityin pellet Pellet

10. Chargaff’s Rules • The relative amounts of adenine and thymine are the same in DNA • The relative amounts of cytosine and guanine are the same. • Named after Erwin Chargaff

11. Rosalind Franklin • Used X-Ray diffraction to get information about the structure of DNA • Died in 1958 at the age of 37 of ovarian cancer

12. Watson and Crick - Structure • 1953 discovered the double helix structure of DNA. • Admitted to using Franklin’s data without her knowledge.

13. Double-helix • A twisted ladder with two long chains of alternating phosphates and sugars. The nitrogenous bases act as the “rungs” joining the two strands.

14. Length of a DNA molecule • The nucleus of one human cell contains approximately 2.5 MILLION nucleotide bases. • One cell has about 1.7m of DNA if unwound • That means DNA in every cell in your body could stretch to the MOON and BACK 1500 times!

15. How does it all fit into a cell’s nucleus? • Histones = DNA tightly wrapped around a protein

16. As you come in, • Materials: • Molecular Biology notes pages • PICK UP Intro to DNA Internet workshop • Plan: • DNA Structure and Replication notes • Intro to DNA Workshop (Look up Karyotype Disorder if needed, too!) • Complete Understanding DNA Worksheet • Homework: • Finish any incomplete classwork

17. Molecular Biology of the Gene Nucleic Acids DNA RNA

18. Nucleic Acid Review • Made of monomers called nucleotides • Nucleotides are made up of • a 5-carbon sugar • phosphate group • a nitrogen base • Types • RNA (ribonucleic acid) • DNA (deoxyribonucleic acid) • Functions • Store hereditary information (DNA) • Transmit hereditary information (RNA)

19. DNA • Polymer of nucleotides • Made of monomers of deoxyribonucleotides • In DNA, the nucleotides of TWO strands will come together • The two strands will connect at the nitrogen bases with hydrogen bonds and twist forming a DOUBLE HELIX

20. Phosphate group Nitrogenous base Nitrogenous base(A, G, C, or T) Sugar Phosphategroup Nucleotide Thymine (T) DNA nucleotide Sugar(deoxyribose) Polynucleotide Sugar-phosphate backbone

21. DNA Bases Thymine (T) Cytosine (C) Adenine (A) Guanine (G) Pyrimidines Purines Single ring structure Double ring structure

22. mRNA rRNA tRNA RNA • Made of monomers of ribonucleotides • Only occurs in SINGLE-STRANDED form • Three main types

23. RNA vs. DNA Nitrogenous base(A, G, C, or U) • 3 Differences: • RNA has a different sugar (ribose). • RNA has Uracil instead of Thymine. • RNA is a single strand. Phosphategroup Uracil (U) Sugar(ribose)

24. Structure of DNA • Consists of 2 polynucleotide strands wrapped around each other in a double helix Twist

25. Base Pairs • Strands are held together by hydrogen bonds. • “Complementary Base Pairing” • In DNA (A, T, C, G) • Adenine will base pair with Thymine • 2 H-bonds between • Cytosine will base pair with Guanine • 3 H-bonds between • In RNA (A, U, C, G) • Adenine will base pair with Uracil • Cytosine will base pair with Guanine

26. DNA Bases

27. DNA Replication • Each time a cell divides, it must first make a copy of its chromosomes (which are made of DNA) • Throughout the process, one strand of the DNA molecule will be “conserved” and one will be given away… • This is known as “semiconservative replication”… • Resulting strands will contain one old strand and one new strand

28. DNA Replication • In DNA replication, the strands separate. • Enzymes use each strand as a template to assemble the new strands. A A Nucleotides Parental moleculeof DNA Both parental strands serveas templates Two identical daughtermolecules of DNA

29. DNA Replication: A Closer Look • DNA replication begins at specific sites • Begins when HELICASEunwinds a segment of the DNA and breaks hydrogen bonds between the two complimentary strands of DNA • Helicase “unzips” the helix

30. Each strand of the double helix is oriented in the opposite direction • 5’to 3’ is forward or leading strand (has to do with “where” the phosphate group is hanging off) • 3’to 5’ is the lagging strand 5 end 3 end P P P P P P P P 3 end 5 end

31. How Daughter Strands are Synthesized • Leading Strand • Daughter will be synthesized continuously with DNA POLYMERASE(from 3’ to 5’) • Lagging Strand • Since DNA POLYMERASEcan only add a new nucleotides to a free 3’ end, this strand is DIScontinuouslysynthesized • RNA PRIMASEattaches to the DNA and synthesizes many short RNA primers • DNA POLYMERASE will then remove the RNA primers and replace them with DNA

32. 3 DNA polymerasemolecule 5 5 end Daughter strandsynthesizedcontinuously Parental DNA 5 3 Daughter strandsynthesizedin pieces 3 P 5 DNA Helicase • Finally, DNA Ligaseinserts phosphates into any remaining gaps in the sugar-phosphate backbone 5 P 3 DNA ligase Overall direction of replication

33. As you come in, • Materials: • Molecular Biology notes pages • PICK UP Simulating Protein Synthesis handout • Plan: • Protein synthesis notes • Simulating Protein Synthesis handout • Homework: • Complete Nucleic Acids packet • Watch linked CrashCourse Transcription & Translation video

34. The Flow of Genetic Information from DNA to RNA to Protein The DNA genotype is expressed as proteins, which provide the molecular basis of phenotypic traits.

35. “VocabuLarry” • Genotype vs Phenotype • Every living organism is the outward physical manifestation of internally coded, inheritable, information. • Outward physical manifestation = phenotype • Internally coded, inheritable information = genotype • Understand now? “The DNA genotype is expressed as proteins, which provide the molecular basis of phenotypic traits.” • The information constituting an organism’s genotype is carried in its sequence of bases.

36. A specific gene specifies a protein • DNA is transcribed into RNA which is translated into the protein. DNA TRANSCRIPTION RNA TRANSLATION Protein

37. How? • Genetic information transcribed in codons is translated into amino acid sequences. • CODON = words in DNA language; triplets of bases that RNA uses to specify a protein • The codons in a gene specify the amino acid sequence of a protein. • EXAMPLE: • Amino acid chain: Lysine – serine – leucine– glutamic acid • A triplet of DNA bases codes for an amino acid. • The order of the DNA bases leads to the order of the amino acids. • The order of the amino acids leads to the phenotype (physical trait).

38. Transcription • Through transcription, the DNA code is transferred to mRNA in the NUCLEUS. • DNA is unzipped in the nucleus and RNA polymerase binds to a specific section where an mRNA will be synthesized. Transcribe: To make a written copy

39. mRNA rRNA tRNA Types of RNA • Messenger RNA (mRNA) • Long strands of RNA nucleotides that are formed complementary to one strand of DNA (TRANSCRIPTION) • Ribosomal RNA (rRNA) • Associates with proteins to form ribosomes in the cytoplasm • Transfer RNA (tRNA) • Smaller segments of RNA nucleotides that transport amino acids to the ribosome

40. Transcription to Genetic Code • mRNA now has a transcribed copy of the DNA codons • mRNA is moved to the ribosome where it is read.

41. Gene 1 Gene 3 DNA molecule Gene 2 DNA strand TRANSCRIPTION RNA Codon TRANSLATION Protein Amino acid

42. The Genetic Code is the Rosetta stone of life

43. Translation • In translation, tRNA molecules act as the interpreters of the mRNA codon sequence. • At the middle of the folded strand (of tRNA) there is a three-base coding sequence called the ANTI-CODON. • Each anti-codon is complementary to a codon on the mRNA. • tRNAs add amino acids to a growing polypeptide chain as the mRNA molecule moves through the ribosome one codon at a time. • When the STOP codon is reached, translation terminates and the polypeptide is released.

44. An exercise in translating the genetic code Transcribed strand DNA Transcription RNA Startcodon Stopcodon Translation Protein

45. An exercise in translating the genetic code Transcribed strand DNA Transcription RNA Startcodon Stopcodon Translation Protein

46. An exercise in translating the genetic code Transcribed strand DNA Transcription RNA Startcodon Stopcodon Translation Protein

47. An exercise in translating the genetic code Transcribed strand DNA Transcription RNA Startcodon Stopcodon Translation Protein

48. An exercise in translating the genetic code Transcribed strand DNA Transcription RNA Startcodon Stopcodon Translation Protein

49. An exercise in translating the genetic code Transcribed strand DNA Transcription RNA Startcodon Stopcodon Translation Protein

50. An exercise in translating the genetic code Transcribed strand DNA Transcription RNA Startcodon Stopcodon Translation Protein