Download 12.1 * The Genetic Code

12.1 – The Genetic Code
Essential Questions:
1.
What forms the genetic code?
2.
How does DNA copy itself?
What Forms the Genetic Code?
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Sugar Molecules (Deoxyribose)
Phosphate Molecules
Nitrogen Bases
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Adenine (A)
Thymine (T)
Guanine (G)
Cytosine (C)
What Forms the Genetic Code?
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Smallest
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Nitrogen Bases
DNA
Gene
Chromosome
Cell Nucleus
Cell
Largest
DNA, Genes, and Chromosomes
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DNA – Twisted ladder of nitrogen bases.
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All body cells contain DNA except red blood cells.
Gene – A section of DNA that contains the code for
one specific protein.
Chromosome – A collection of genes.
Order of the Bases
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The order of the
nitrogen bases along a
gene forms the genetic
code that creates a
specific protein.
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Proteins are made of
amino acids.
How Does DNA Copy Itself?
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When one cell divides and becomes two daughter cells,
DNA needs to be copied.
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This is called DNA replication.
How Does DNA Copy Itself?
DNA unwinds and separates.
Nitrogen bases pair up.
1.
2.
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3.
Adenine always pairs with Thymine
Cytosine always pairs with Guanine
Two identical DNA strands are formed.