DNA: The Genetic Material

Identifying the Genetic Material Experiments of Griffith and Avery yielded results that suggested DNA was genetic material (1944) Experiments of Griffith and Avery yielded results that suggested DNA was genetic material (1944)

Hershey & Chase used the bacteriophage T2 and radioactive labels to show that virus genes are made of DNA, not protein (1952) Hershey & Chase used the bacteriophage T2 and radioactive labels to show that virus genes are made of DNA, not protein (1952)

DNA stores information that tells cells which proteins to make and when to make them DNA stores information that tells cells which proteins to make and when to make them

The Structure of DNA Discovered by Watson & Crick in 1953 & received Nobel Prize in 1962 along with Maurice Wilkins Discovered by Watson & Crick in 1953 & received Nobel Prize in 1962 along with Maurice Wilkins =sf0YXnAFBs8&feature=autoplay& list=PL4900A D0&lf=res ults_video&playnext=2

DNA  Polymer : Nucleotide  Monomer DNA  Polymer : Nucleotide  Monomer Each Nucleotide has 3 parts: Each Nucleotide has 3 parts: 1) 5 carbon sugar  Deoxyribose 1) 5 carbon sugar  Deoxyribose 2) Phosphate group  PO 4 2) Phosphate group  PO 4 3) Nitrogen Base 3) Nitrogen Base

Nitrogen Bases Purines Adenine Guanine Pyrimidines Thymine Cytosine

DNA forms a spiral ladder  Double Helix DNA forms a spiral ladder  Double Helix Double helix is held together by weak Hydrogen bonds Double helix is held together by weak Hydrogen bonds Erwin Chargaff Discovery  Chargaff’s Rule  A=T, G=C Erwin Chargaff Discovery  Chargaff’s Rule  A=T, G=C ATGC Human Plant Virus

DNA Replication Phase of Cell Cycle? Why replicate? Phase of Cell Cycle? Why replicate? Step 1: DNA Helicase unzips DNA by breaking weak Hydrogen bonds. Step 1: DNA Helicase unzips DNA by breaking weak Hydrogen bonds. Step 2: DNA polymerase adds nucleotides to exposed nitrogen bases. Step 2: DNA polymerase adds nucleotides to exposed nitrogen bases. Step 3: Two DNA molecules form that are identical to original. Step 3: Two DNA molecules form that are identical to original.

DNA is referred to as “Semi-conservative”, Each DNA molecule  1 template & 1 new strand DNA is referred to as “Semi-conservative”, Each DNA molecule  1 template & 1 new strand DNA polymerase proofreads DNA during its replication so that very few errors occur DNA polymerase proofreads DNA during its replication so that very few errors occur watch?v=zdDkiRw1PdU

500/sec bacteria 500/sec bacteria 50/sec human 50/sec human

Eukaryotes Eukaryotes

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