Wilkins
Crick
Watson
Franklin
nucleotide
Why do offspring resemble
their parents?
• The offspring have copies of the parents’ chromosomes
• Chromosomes contain sets of instructions
• Those instructions are called GENES
• Genes are made up of DNA
In what year was DNA finally concluded to be genetic
material?
•1944
HINT: D-Day: This is the U.S. Coast Guard at Normandy
the three parts of a
NUCLEOTIDE?•Nitrogen base
•Phosphate
5-carbon sugar molecule (deoxyribose)
The letters DNA stand for what words?
•Deoxyribonucleic•acid
4 different NITROGEN bases
•Adenine•Thymine
•Guanine•cytosine
Class of organic molecules for ADENINE and GUANINE
•purines
LARGE
Class of organic molecules for thymine and cytosine
•pyrimidines
SMALL
Purines have how many rings of carbon and nitrogen atoms?
•2
Pyrimidines have how many rings of carbon and nitrogen
atoms?
•1
Base-pairing rule
•Thymine always goes with Adenine
•Cytosine always goes with Guanine
•Watson, Crick and Wilkins
3 scientists who won the Nobel Prize by
understanding the 3-deminsional structure of DNA
1953………Nobel Prize in 1962
Only males were allowed
in the university
dining rooms, and after hours
Franklin's colleagues
went to men-only pubs.
Rosalind Franklin
Describe a double helix
Spiral staircase
In the DNA structure of the ‘twisted ladder’
(spiral staircase) the rungs are held
together by what bond?
•HYDROGEN
The process of making a new DNA strand is called
•REPLICATION
Before REPLICATION can begin
•The double helix must be UNWOUND
The UNWINDING of the DNA strand is
accomplished by
•ENZYMES called
• HELICASES
Differences between DNA and RNA
DNA RNA2 strands of nucleotides
Single strand of nucleotides
5-carbon sugar deoxyribose (‘de’ means without an OH)
5-Carbon ribose (sugar)
thymine Uracil
Now you try it
Draw 5 pairs of nucleotides, labeling each part.