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DNA stands for:
D: Deoxyribose
N: Nucleic
A: Acid
DNA is too
small to see,
but under a
microscope it
looks like a
twisted up
ladder!
Every living thing has DNA. That means
that you have something in common with a
zebra, a tree, a mushroom and a beetle!!!!
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1800’s Scientists know that the nuclei of cells
contain large molecules called nucleic acids.
1950 chemist learn DNA is made of but not
how it is arranged
1952 Rosalind Franklin that DNA is two
chains of molecules in a spiral form
•
established by
James Watson
and Francis Crick
•
Shape of a double
helix

4 nitrogen bases (rungs of the DNA ladder)
Adenine, guanine, cytosine, and thymine
Which are abbreviated A, G, C, and T
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The amount of C = amount of G
The amount of A= amount of T
One side:
Other side:
A T A
T C A
T G C
G G G
The combination of A,T,G,C determines what
traits you might have, for ex.
C A T C A T = purple hair
T A C T A C = yellow hair
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DNA unzips and replicates new base pairs to
match the existing ones on each strand
Sections of DNA on a
Chromosome
 Contain instructions for making
specific protein
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Contain the information needed to make
specific proteins
Each chromosome contains hundreds of genes
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Ribonucleic Acid
Like DNA but only one side of the ladder
3 kinds of RNA
1. Messenger RNA (mRNA)
2. Ribosomal RNA (rRNA)
3. Transfer RNA (tRNA)
2. RNA carries the codes for making proteins
from the nucleus to the ribosomes in the
cytoplasm
a.
Messenger RNA carries the code that directs
the order in which the amino acids bond
b. Ribosomal RNA makes up Ribosomes, where
proteins are built
c.
Transfer RNA brings amino acids to the
ribosomes to build the protein.
3. Cells use only the genes that directs the making
of proteins needed by that cell.
RNA carries the
"message" to the
ribosomes, where
proteins are made
1.
2.
Can be caused by outside factors
like Xrays, sunlight, and some
chemicals have been know to
cause mutations.
A change in a gene or
chromosome can change the
traits of an organism.
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A.
B.
C.
D.
E.
F.
DNA
A = adenine
T = Thymine
Phosphate
Sugar (deoxyribose)
G = Guanine
C = Cytosine