Presentation on theme: "Deoxyribonucleic Acid. Double Helix James Watson and Francis Crick developed a model They used clues through Franklin’s experiment Their model is a double."— Presentation transcript:
Double Helix James Watson and Francis Crick developed a model They used clues through Franklin’s experiment Their model is a double helix (a spiral consisting of 2 strands in a surface of a cylinder that coil around its axis).
Definition Nucleic acid that contains the sugar deoxyribose It is the hereditary material in humans and almost all other organisms
DNA VRML* http://www.chm.bris.ac.uk/motm/dn a/dnav.htm Paul May, School of Chemistry, University of Bristol http://www.chm.bris.ac.uk/motm/dn a/dnav.htm Paul MaySchool of Chemistry
DNA Structure Made of nucleotides Nucleotides made of deoxyribose (5- carbon sugar), phosphate and a nitrogenous base The four bases are adenine, thymine, cytosine and guanine
Nitrogenous Bases Purines: Adenine and Guanine Purines are the larger of the two types of bases found in DNA. Pyrimadines:Cytosine and thymine
DNA Replication Each half of a DNA double helix has the information to reconstruct the other half Complimentary strands: A-T and C-G Replication occurs on 100’s of points Replication proceeds in both directions A replication fork is where the chromosome separates and replicates
Duplicating DNA Occurs before the cell divides DNA molecule separates Each strand produces a new complimentary strand: Example: Strand one A-T-G-C-C-T Complimentary strand U-A-C-G-G-A
Duplicating DNA Enzymes “unzip” the DNA molecule (hydrogen bond between base pairs are broken) Each strand of DNA becomes a template for a complimentary strand Principal enzyme involved is DNA Polymerase (checks for mutations)
Activity “Have Your DNA and Eat It Too!”* In the activity, you will be given the following items: 2 pieces of licorice 12 toothpicks 36 marshmallows 5 paperclips Masking tape You are to construct a strand of DNA and its complimentary strand. If you are a #1, your strand one is T A C G T A T G A A A C If you are a #2, your strand one is T G G T T T A G A A T T When you are finished, have the instructor check it. *http://gslc.genetics.utah.edu copyright 2004 University of Utah
Research Assignment We will learn how to use the library by getting instructions and practice from Mr. Smith. Handout: Complete the questions on the handout. Check the answers for accuracy.