DNA Structure, Function & Replication

DNA stands for… DeoxyriboNucleic Acid

FUNCTION: Stores Genetic Information

LOCATION: Inside the nucleus of every eukaryotic cell

Alfred Hershey and Martha Chase that helped to confirm that DNA was the genetic material.

James Watson, Francis Crick, and Maurice Wilkins received the Nobel Prize for discovering the structure of DNA Watson Wilkins Crick

BUILDING BLOCKS Nucleotides are the building blocks of nucleic acids

NUCLEOTIDE COMPOSITION Sugar - Deoxyribose Phosphate 1 of 4 bases –Adenine –Thymine –Cytosine –Guanine

SHAPE: Spiral staircase Twisted ladder Double helix

The Untwisted Ladder Sides of ladder –Deoxyribose Sugar –Phosphate Group Rungs of ladder –Nitrogen bases Adenine (A) Guanine (G) Thymine (T) Cytosine (C)

Chargaff’s base pairing rule A is double bonded to T C is triple bonded to G

DNA REPLICATION is the process where one DNA strand is copied to make 2 identical DNA strands

1.DNA strand unzips – 2 sides separate 2.DNA polymerase adds complementary nucleotides to each strand 3.Two DNA molecules form that are identical to the original DNA molecule

Enzymes that help with replication Helicase: Separates strands DNA Polymerase: adds free nucleotides to the existing strand DNA ligase: joins the backbone of the newly formed DNA strands

Mutations Change in the order of bases