Criteria for Hereditary Material 1)Found in nucleus 2)Arranged into chromosomes 3)Can control heredity 4)Self-replicating

How did scientists show that the transforming material was DNA?

Pneumoniae cell extracts contain protein, DNA, and RNA. How did scientists show that the transforming material was DNA?

Avery, MacLeod and McCarthy 1)Mix dead S and Live R bacteria 2) Add protease 3) Add RNA-ase 4) Add DNA-ase

Conclusion: DNA is the hereditary material! Techno

April 29, 2010 Ms. Simon Regents Biology Do Now: Turn in Lab Activity How did Griffiths show that bacteriophage DNA can “transform”?

DNA Stored in the nucleus as chromosomes Each chromosome is a long strand of DNA Chromosomes are coiled using histones (proteins)

What is the structure of DNA?

DNA= Deoxyribose nucleic acid The monomers of DNA are nucleotides Each nucleotide contains: 1) phosphate (PO4) backbone 2) deoxyribose (5 Carbon sugar) 3) nitrogenous base

Nitrogenous Bases Purines have two rings Pyrimidines have one ring

Chargoff analyzed DNA of different species # Adenine= # Thymine # Guanine= #Cytosine Hypothesis: Maybe A is bound to T and G is bound to C

Rosalind Franklin X-ray diffraction technique- allows her to take pictures of DNA’s structure Helix shape

Watson and Crick Won the Noble Prize for discovering the structure of DNA Model of DNA is a double helix, two strands are wound around each other

Double-helix model Ribose and Phosphate on the outside Nitrogenous bases pair as “rungs” of the ladder equidistant

Nitrogenous bases are bound through weak hydrogen bonds Phosphates and riboses are covalently bonded Adenine and Thymine= 2 hydrogen bonds Guanine and cytosine= 3 hydrogen bonds

Template Strand CTAGTTACACTAGTTACA GATCAATGTGATCAATGT Complementary Strand

During DNA replication, DNA molecule separates into two strands. Two new complementary strands are formed.

Replication is carried out by enzymes that unzip DNA molecule

Helicase- enzyme that unwinds DNA

DNA Polymerase DNA polymerase forms the new strand of DNA