Warm Up 2 1/27 1. From this experiment, Griffith concluded that one strain of bacteria is changed in form by the gene of another. This is called ______________.

2. When DNA is destroyed from heat killed poisonous sample, there is NO transformation. This means that it is _______ that stores and transmits genetic information.

3. Hershey-Chase infected a cell with radioactive DNA, and then with radioactive protein. He concluded that the genetic material of the bacteriophage was ___________ not __________.

DeoxyriboNucleic Acid DNA Structure DeoxyriboNucleic Acid

Nucleotides -make up DNA -has 3 parts Phosphate group Nitrogenous Base Deoxyribose 5 carbon sugar

A C T G G A T C

DNA is made up of _____________________.

The three parts of a nucleotide are:

Nitrogen Bases A Adenine T Thymine C Cytosine G Guanine

Nitrogenous Bases Pure As Gold PURINES Adenine (A) , Guanine (G) PYRIMIDINES Cytosine (C) , Thymine (T) All have Y’s- pYrimidines cYtosine thYmine

Chargaff’s Rule/Base Pairing # of A’s = T’s, # of C’s=G’s Adenine (A)----Thymine (T) bonded by hydrogen bond AT&T PYRIMIDINES Cytosine (C)----Guanine (G) Bonded by hydrogen bond -Cingular

A C T G G A T C

Nucleotides Sugar phosphate backbone Nitrogen bases= steps to ladder

Which are the 2 purines? Which are the 2 pyrimidines?

Chargaff’s Rule states that A- _____ C- _____

Strands in DNA are twisted There are 2 strands Nitrogen bases are near the center

1953 Watson and Crick Watson & Crick’s model of DNA was a double helix in which 2 strands were wound around each other Double helix- 2 stranded spiral

Who are the 2 men that discovered the structure of DNA?

What does double helix mean?