The Structure of DNA
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Transcript of The Structure of DNA
The Structure of DNA
The molecule of life
DNA is a Molecule
Held together with covalent bonds ** Hydrogen Bonds** hold the bases together
(Adenine, Guanine, Cytosine, Thymine)
http://www.envirohealthtech.com/images/DNA.jpg
The Double Helix
http://eur.news1.yimg.com/eur.yimg.com/xp/afpji/20060513/060513030238.z1molysc0_human-dna-double-helix-b.jpg
Ladder-like Structure
The base pairs form the “rungs” The phosphate and deoxyribose sugar form
the uprights
http://academy.d20.co.edu/kadets/lundberg/images/dna.gif
The Sugar Phosphate Backbone
http://www-math.mit.edu/~lippert/18.417/lectures/01_Intro/Pictures/10000000000001B00000023B34B57A9B.jpg
H
O
HHH H
OH
CH2
OH
HO
O
OP
Nucleotide
Phosphate group
Deoxyribose – pentose sugar (5 carbons)
Base (adenine, guanine, thymine, or cytosine)
The basic unit of the DNA molecule
Polynucleotide
A string of nucleotides The order of the bases
determines the genetic code of the organism
The molecule ‘unzips’ and free nucleotides attach to their base-pair partners to form two new double helices
DNA Replication
http://courses.cm.utexas.edu/jrobertus/ch339k/overheads-2/ch10_DNA-rep.jpg
Base PairsA - T
G - C
Semi-conservative Replication
New “daughter” DNA molecules are made up of one strand from the original “parental” DNA molecule and one newly formed strand.
http://nobelprize.org/educational_games/medicine/dna/b/replication/replication_schem.html
The chromosome unwinds
(Chromosomes are tightly packed strands of DNA)
The Process of Replication
http://www.microbeworld.org/news/articles/human_genes.aspx
The hydrogen bonds between the base pairs are broken
The Process of Replication
http://www.ba-education.demon.co.uk/gifs/replication.jpg
The Process of Replication
The two polynucleotide strands separate
http://en.wikipedia.org/wiki/Double_helix
The Process of Replication
Free nucleotides attach to the template made by the parent strands.
And Voilà!! Two identical DNA molecules.
http://www.chemsoc.org/ExemplarChem/entries/2003/imperial_Burgoine/replication.jpg