What does DNA stand for? Deoxyribonucleic acid DNAs Func*ons: —  Controls the production of proteins —  Can copy itself for new cells —  Carries genetic information from one generation to the next Central Dogma:
replication
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video/2933/The-­‐Human-­‐
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Anima*on-­‐Introduc*on II. Structure of DNA —  Monomer of DNA= nucleotide —  DNA is made of 2 chains of nucleotides. —  3 parts of a nucleotide: —  Pentose (5C) sugar= deoxyribose —  Phosphate group —  Nitrogen base Bases in DNA
adenine
purines
N9
guanine
cytosine
pyrimidines
thymine
N1
Complementary bases: —  Watson and Crick deduced that A must pair with T and G with C =complimentary pairs —  Watson and Crick realized in 1953 that the DNA molecule is a Double Helix. Double helix —  The two strands are linked in the center by hydrogen bonds. The sequence of nitrogen bases DNA Replica*on-­‐How DNA is copied —  Before a cell divides,
it s DNA is copied so
each new cell gets a
complete set of DNA
Replica*on=process of copying DNA 1. 
2. 
3. 
4. 
An enzyme unzips the DNA molecule by
breaking the hydrogen bonds
New nucleotides pair up with the original
nucleotides
Two identical DNA strands are produced
http://www.hhmi.org/biointeractive/dna/
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—  Mutation- a mistake in DNA structure
—  Mutagen- environmental agents that alter DNA
structure
—  Examples: radiation, viruses, chemicals (cigarette
smoke)