Download Guanine – Cytosine

If you unraveled all your chromosomes from all
of your cells and laid out the DNA end to end,
the strands would stretch from the Earth to
the Moon about 6,000 times.
DNA nucleotides
Phosphate group
Nitrogenous base
Pentose sugar
Nucleotide
Polynucleotide
chain
Sugar phosphate
backbone
4 different bases
G
C
A
T
two groups of bases:
Purines- ADENINE (A) and GUANINE (G)
Pyrimidines- THYMINE (T) and CYTOSINE
(C)
• -- Only 2 combinations of base pairs can form
the rungs of the DNA molecule.
Adenine - Thymine (A-T)
AND
Guanine – Cytosine (G-C)
• --This specific matching up of the nitrogenous
bases is called complementary base pairing.
Okay… show the resulting base pairings below!
ATGCCTACGTTAGATTACAACCTAAGCAAT
TACGGATGCAATCTAATGTTGGATTCGTTA
Did you find the hidden word?! 
• DNA- TACGCATACGATTC
• DNA• mRNA• tRNA• AA-
• DNA mRNAtRNA Amino Acid Protein
In 1996 Wilmut et al used a
similar method to clone the
first mammal, Dolly.
Since then many different
species of mammal have
been cloned, and their is
serious debate about the
cloning of humans.