1. Ch.6s.1 Genetics: History and Structure of DNA
First Last
Date
Period #
Chromosome
DeoxyriboNucleic Acid
Since chromosomes contain both protein and DNA, scientists did not know which one contained the instructions, the gene.
The gene must do two things: have instructions for cell processes and for building cell structures, and must be copied each time a cell divides
DeoxyriboNucleic Acid (DNA) was thought to be a simple molecule, so most scientists thought genes were made of protein

2. Ch.6s.1 Genetics: History and Structure of DNA
First Last
Date
Period #
nucleotide
Sugar
Phosphate
Nucleotide base (A, T, C, G)
Chargaff’s rule
A unit of DNA is a strand composed of subunits called nucleotides.
Each DNA nucleotide is composed of a sugar (deoxyyribose), phosphate, and nucleotide base. <<<draw picture>>>
Chargaff found that the amount of T=A and G=C in a sample of DNA

3. Ch.6s.1 Genetics: History and Structure of DNA
First Last
Date
Period #
Maurice Wilkins
Rosalind Franklin
Watson
Double helix
Nobel Prize
Maurice Wilkins and his student, Rosalind Franklin, used X-ray diffraction to determine DNA has a spiral shape.
James Watson and Francis Crick examined Franklin’s work and determined that DNA is a double helix of sugar and phosphate connected by pairs of bases
Crick, Watson & Wilkins shared Nobel Prize in 1963

4. Ch.6s.1 Genetics: History and Structure of DNA
First Last
Date
Period #
Double helix
Twisted ladder
Adenine (A)
Thymine (T)
Guanine (G)
Cytosine (C)
Base-pairing rules
On the double helix, or twisted ladder, the rails of the ladder are made from alternating sugar and phosphate; the rungs of the ladder are made from nucleotide base-pairs. <<<draw picture>>>
The nucleotide bases on DNA are adenine (A), thymine (T), guanine (G), and cytosine (C).
They always bond according to the base-pairing rules: A-T and G-C. <<<draw picture>>>

5. Ch.6s.1 Genetics: History and Structure of DNA
First Last
Date
Period #
complementary
X: AGTCGAC
TCAGCTG
Replicate
template
A is complementary to T and G is complementary to C, so the sequence of bases on one entire strand of DNA is always complementary to the sequence of bases on the entire other strand
A replicate of one strand is made by separating the two strands, and attaching complementary nucleotides to each strand
Each OLD strand is a template to build each NEW strand on
Each replicate has one OLD template and one NEW strand