Presentation on theme: "FINDING DNA. National DNA DAY April 15, 2011 National DNA Day commemorates the successful completion of the Human Genome Project in 2003 and the discovery."— Presentation transcript:
National DNA DAY April 15, 2011 National DNA Day commemorates the successful completion of the Human Genome Project in 2003 and the discovery of DNA's double helix by James Watson and Francis Crick in 1953.
Proof of DNA as Genetic Material Was the genetic material protein or DNA? Mendel (peas) and Morgan (flies) did not know it was DNA.
Did you know… Every cell in your body has the same DNA (you got it from Dad and Mom). The reason the cells look different is because different genes were turned on.
Frederick Griffith A medical officer was trying to find a vaccine against pneumococcus
Rough and Smooth Pneumococcus
Griffith 1920’s Transformation
Griffith’s Conclusion harmless R cells (pneunomia) used the genetic information from the dead S cells and became harmful = transformation = passing the inheritance factor from one organism to another
Oswald Avery He had reported that DNA, not protein (which was believed at the time), was the hereditary substance.
Oswald Avery 1940’s Separated: RNA DNA Protein Caused S strain to cause pneumonia Gave each to mice Simple centrifuge video
Alfred Hershey and Margaret Chase 1953 Showed that the hereditary material in bacteriophage viruses is DNA. McGraw Hill Ani
Hershey-Chase CONCLUSION – DNA is genetic material because ( 32 P) DNA not ( 35 S) protein guides viral replication
Bacteriophages (“bacteria-eaters”) Mostly made of just protein coat and DNA
Virus: Are they Alive? Viruses can only replicate in a living host.
pp Bacteriophage Lytic Infection 1.Attach to host 2. Insert DNA 3. Make and assemble DNA parts 4. Lyse (burst) Bacteriophage Infection Video
Examples: Cold Flu
Lysogenic Infection BIOL 230 Lecture Guide - Lysogenic Life Cycle of a Temperate Bacteriophage (animation link)BIOL 230 Lecture Guide - Lysogenic Life Cycle of a Temperate Bacteriophage 1. Virus lands on host. 2. Virus injects DNA into host. 3. Virus DNA attaches to host DNA = prophage. 4. Virus Prophage will become lytic when conditions are favorable (you are sick, tired).
Lysogenic Cycle Animation EXAMPLES: HERPES HIV GOOD ONE! McGraw Hill Lytic- Lysogenic AnimationMcGraw Hill Lytic- Lysogenic Animation Herpicide-SWEET Valtrex
Click on “Journey into DNA” NOVA Online | Cracking the Code of Life | Journey into DNA (keep clicking on “zoom” + button)NOVA Online | Cracking the Code of Life | Journey into DNA
What is the structure of DNA? It is a nucleic acid Polynucleotide = Made of long chains of Nucleotides
DNA Nucleotide O O=P-O OPhosphate Group Group N Nitrogenous base (A, G, C, or T) (A, G, C, or T) CH2 O C1C1 C4C4 C3C3 C2C2 5 Sugar Sugar(deoxyribose)
DNA Structure NUCLEOTIDEPOLYNUCLEOTIDE
A Nucleotide MADE OF: –Sugar –Phosphate –Base Deoxyribose sugar PO 4 4 kinds: (A) (G) (T) (C) (names on next slide)
4 Types of Base Pairs A = adenine T = thymine C = cytosine G = guanine NOW SING THE DNA SONG
Nitrogenous Bases PURINES -2 ringsPURINES -2 rings Adenine (A) 1.Adenine (A) Guanine (G) 2.Guanine (G) PYRIMIDINES -1 ringPYRIMIDINES -1 ring Thymine (T) 3.Thymine (T) Cytosine (C) 4.Cytosine (C) T or C A or G
DNA Deoxyribonucleic Acid (Get out colored pencils)
DNA Double Helix Nitrogenous Base (A,T,G or C) “Rungs of ladder” “Legs of ladder” Phosphate & Sugar Backbone
DNA Structure Rungs of the Ladder: –Various orders of A, T, C, G Backbone: –Sugar and phosphates –Alternate
DNA Double Helix P P P O O O P P P O O O G C TA
The other nucleic acid: RNA Ribonucleic Acid Three types: –mRNA (messenger) –tRNA (transfer) –rRNA (ribosomal)
THE RNA’s JOBS mRNArRNAtRNA Takes code out of nucleus to ribosome Part of the structure of the ribosome Takes amino acids to ribosomes
Comparing DNA and RNA DNA Double stranded Sugar = deoxyribose Bases: A-T, C-G Found only in nucleus Can repair itself RNA Single stranded Sugar = ribose Bases: A-U, C-G Found in and out of the nucleus Cannot repair itself
RNA DNA Making mRNA
Pretty Similar Uracil Thymine
DNARNA - Contains Thymine - Contains deoxyribose sugar - Double stranded molecule - Found only in nucleus - Single stranded molecule - Contains uracil - Contains ribose sugar - Found in nucleus and cytoplasm - Made of nucleotides - Contain adenine, guanine and cytosine Both
Relative Proportions (%) of Bases in DNA Organisms A T G C Human Chicken Grasshopper Sea Urchin Wheat Yeast E. coli
Question: Adenine CytosineIf there is 30% Adenine, how much Cytosine is present? HINT: A –T and C - G
Answer: CytosineThere would be 20% Cytosine. Adenine (30%) = Thymine (30%) Guanine (20%) = Cytosine (20%) Total of 100% Total of 100%
Chargaff’s Rules the amount of (A)denine will always equal the amount of (T)hymine And the amount of (G)uanine will always equal the amount of (C)ytosine. HOT!!!
Nitrogenous Bases Why does A bond only with T and C only with G? What do you notice?
Nitrogenous Bases T and C are single-ring Pyrimidines A and G are double-ring Purines A single bonds with a double
2 chains of nucleotides bind to form a DNA molecule Hydrogen bonds form between the nitrogenous bases to join the 2 chains together The sugar and phosphate group together is known as the sugar-phosphate backbone
ENZYMES FOR DNA REPLICATION Helicase = separates 2 DNA strands (breaks H bonds) Primase=RNA primers at INITIATION
REPLICATION ENZYMES Topoisomerase = unwinding DNA DNA Polymerase = Adding of DNA nucleotides ELONGATION (proofread and repair)
DNA REPLICATION ENZYMES LIGASE= Binds the Okazaki fragments Watch the enzymes in DNA Replication AnimationWatch the enzymes in DNA Replication Animation
AT and C-G Base Pairing DNA Replication simple version) (link)DNA Replication Media Showcase (cool animation link)Media Showcase Detailed Replication Link
DNA STRUCTURE A-T C-G in tons of combinations makes our genetic code
DNA Replication Hi!...Still Awake? DNA Replication Animation click hereDNA Replication Animation
What is the complementary base sequence on the other strand of the DNA? T A A C G G G A T T A T T G C C C T A A
The Race is On! To Determine the Structure of the DNA molecule.
DNA Geek Rosalind Franklin was an English chemist who was working in an X-ray crystallography lab in Paris, France in FAMOUS PHOTO 51 (correct orientation of DNA- double helix)
X ray Diffraction
Linus Pauling American biochemist suggested helix (spiral)shape Most famous for Vitamin C prevents colds
DNA Geek Linus Pauling was a Caltech chemist (USA), who in 1951 had discovered the alpha helical nature of protein structure. I remember his books: Vitamin C and the Common Cold and Cancer and Vitamin C also The Nature of the Chemical Bond and protested nuclear testing
DNA Geeks James Watson, a biologist from Indiana University, and Francis Crick, a physicist, were working at the Cavendish Lab in Cambridge, England Nobel Prize for structure of DNA
Watson and Crick’s Wire Model DOUBLE HELIX First put the nitrogenous bases on the outside (incorrectly)
Beadle and Tatum Beadle and Tatum experiment animationBeadle and Tatum experiment
Happy DNA DAY The day commemorates the completion of the Human Genome Project in April 2003, and the discovery of DNA's double helix. DNA SongDNA Song NOVA | Ghost in Your Genes | PBS