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DNA Is In All of Your Cells Body Fluids and Tissues

DNA Is In All of Your Cells Body Fluids and Tissues. Blood Semen Saliva Perspiration Tissue Bones and Teeth Hair (if there is tissue on the root) Urine, Feces, Vomit. You Leave DNA Everywhere. Cigarette butts Stamps and Envelope flaps Drinking cups and Bottles Caps Gum Ear plugs

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DNA Is In All of Your Cells Body Fluids and Tissues

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  1. DNA Is In All of Your CellsBody Fluids and Tissues • Blood • Semen • Saliva • Perspiration • Tissue • Bones and Teeth • Hair (if there is tissue on the root) • Urine, Feces, Vomit

  2. You Leave DNA Everywhere • Cigarette butts • Stamps and Envelope flaps • Drinking cups and Bottles • Caps • Gum • Ear plugs • Telephone receiver

  3. Masks and Caps • Items commonly used by bank robbers to disguise themselves • DNA can be obtained from the saliva left on the mask or from the sweatband of a baseball cap

  4. Chewing Gum • A ring of thieves would steal cars to use as their “get-a-way” vehicles. • Gum taken from the ignition switch of the stolen cars matched one of the suspects • He confessed and led police to the others involved

  5. Bandages • Bank robber covered his face with bandages to disguise himself • He threw them away outside the bank • DNA recovered from the adhesive portion matched the suspect

  6. Why is DNA Testing Valuable? • can be retrieved from evidentiary stains and tissues • tests are available • DNA is unique to you (unless you have an identical twin) and therefore very discriminating • Your DNA is the same, regardless of the body fluid or tissue from which it is obtained • Therefore, DNA obtained from a semen stain from an evidentiary item can be compared to that from a suspect’s blood sample • We can “amplify” very small amounts of DNA for analysis using the Polymerase Chain Reaction (PCR)

  7. DNA Basics • DNA is a molecule located in the nucleus of a cell • Every cell in an organism contains the same DNA • Characteristics of DNA varies between individuals within a species and between species

  8. What is DNA?

  9. Figure 9–1  How nucleotides can be linked to form a DNA strand. S designates the sugar component, which is joined with phosphate groups (P) to form the backbone of DNA. Projecting from the backbone are four bases: A, adenine; G, guanine; T, thymine; and C, cytosine.

  10. Double-stranded polymer made up of nucleotides. Phosphoric acid and deoxyribose sugar form backbone Cytosine always bonds to guanine (C-G) Adenine always bonds to thymine (A-T) C-G and A-T referred to as base pairs DNA basics:

  11. Label the DNA molecule shown below. • Word List: • Cytosine Adenine Thymine Guanine Backbone • Hydrogen Bonds • BACKBONE • CYTOSINE • THYMINE • GUANINE • ADENINE • N BONDS

  12. What is DNA? • DNA stands for deoxyribonucleic acid and contains genetic information. Itis found on chromosomes located in the nucleus of our cells. • What makes up DNA? • The sides or backbone of the DNA molecule are made up of sugar (deoxyribose) and phosphate molecules. • The rungs that form the middle of the molecule are made up of pairs of nucleotides or nitrogen bases. Adenine (A) pairs with thymine (T), while guanine (G) always pairs with cytosine (C). • The order of the bases determines the genetic code. Double Helix DNA Image: http://science.howstuffworks.com/genetic-science/dna-evidence.htm

  13. Identify the complementary strand for the following strand of DNA: -C-A-A-T-G-G-A-G-A-

  14. DNA is contained in chromosomes • Chromosomes contain DNA and associated proteins (which allow the DNA to condense/wind up tightly)

  15. Inside each human cell:

  16. 23 pairs of human chromosomes:one from each parent (Karyotype)

  17. What is a chromosome? • Tightly packed • DNA wrapped • around histone • proteins

  18. Chromosomes, DNA, genes, and nucleotides • Chromosomes contain genes • Genes are sequences of DNA nucleotides (1 section of 3 nucleotides code for a specific amino acid (codon), that strings together with other amino acids to make up proteins) • Chromosomal regions in between genes contain variable nucleotide sequences

  19. Figure 9–3(a) A string of amino acids composes one of the protein chains of hemoglobin. (b) Substitution of just one amino acid for another in the protein chain results in sickle-cell hemoglobin.

  20. Genetic variation • Alleles are differences (variation) in a gene within a population of a species • Genes determine phenotype (physical characteristic) of a structure, molecule, etc.

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