Modern Genetics

DNA Genetic material in the chromosome. DNA=Deoxyribonucleic acid DNA is made up of small subunits called nucleotides. DNA is found in the nucleus.

The Nucleotide Each nucleotide consists of 3 parts: 5 carbon sugar called deoxyribose Phosphate group Nitrogenous base

Four bases: The Nitrogen Bases Adenine (A) Thymine (T) Guanine (G) Cytosine (C)

Types of Nitrogen Bases Purines: Adenine (A) Guanine (G) Pyrimidines: Thymine (T) Cytosine (C)

Base Pairing Rule A pairs with T C pairs with G Held together by Hydrogen Bonds

Watson and Crick Model of DNA Shape of DNA Double helix, twisted ladder Sides of the ladder consists of alternating sugar phosphate molecules Rungs of the ladder consist of nitrogenous base pairs

The Story of the DNA’s Discovery http://www.hhmi.org/biointeractive/double-helix

DNA Replication Double stranded DNA molecule unzips along the hydrogen bonds located between nitrogen bases. Free nucleotides that are present in the nucleus attach themselves to the exposed bases. The new double stranded DNA molecules that are identical to the original molecule are produced.

http://www.youtube.com/watch?v=zdDkiRw1PdU

Helicase & DNA Polymerase