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.