Forensics Chp. 12 DNA Analysis DNA Structure Forensics Chp. 12 DNA Analysis

DNA Structure A gene is a long section of a DNA molecule whose sequence of building blocks specifies the sequence of amino acids in a particular protein. Protein- fundamental component of living cells Enzymes Hormones Antibodies Hemoglobin Insulin

How does DNA work DNA (nucleic acid)  RNA  Ribosome Amino Acids  Protein  Do a job (perform a function) An Analogy can help you remember this: Come up with your own…(5 min.) Ex: Build a house DNA is the blue prints (instructions) Amino Acids are the lumber Proteins are the house…

DNA Structure View from the side - Helix Partially unwound double helix so you can see components

Views from the top Model X-Ray Photo-51

DNA composed of nucleotides Sugar (deoxyribose) Phosphate group Nitrogenous bases A - T C - G

A 5 C sugar and a phosphate group form the backbone DNA Structure A 5 C sugar and a phosphate group form the backbone

Nitrogenous bases DNA Structure A, T, C, & G make up the rungs on the ladder

Complimentary Base Pairing Bases held together with Hydrogen bonds- WEAK BONDS Guanine pairs with Cytosine Triple bond Adenine pairs with Thymine Double bond

DNA Structure 3D Video Clip (Click next 4 times)

3 methods to analyze DNA RFLP- Restriction Fragment Lengths Polymorphism Restriction enzymes cut DNA up Not best method because we need a lot of DNA PCR – Polymerase Chain Reaction Polymerase – enzyme that replicates (makes more) DNA STR – Short Tandem Repeats Specific sequences of DNA fragments that are repeated at a particular site on a chromosome

Replication Technology Mitochondrial DNA- from mom only good for hair, teeth, and bone PCR- Perhaps the most successful technology to ever emerge from LIFE SCIENCE!!! Many Uses Forensics- blood, convict, exonerate false accusations Agriculture, Vet., Medicine, Envi. Sci., Microorganisms, viruses, parasites…