DNABlueprints of life
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WHAT IS DNA? DNA stands for: DeoxyiriboNucleic Acid Code that stores a cell’s hereditary
materialContains info for cell’s growth and function
DNA is copied during passed on to daughter cells during cell division
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STRUCTURE OF DNA 1952: Scientist Rosalind Franklin
discovers the Double HelixTwo chains of molecules in a spiral formSimilar to a twisted ladder
Referred to as “Twisted Ladder” Each side of the ladder is made up of
sugar-phosphate molecules Each molecule consists of the sugar
called dioxyribose and a phosphate group
STRUCTURE OF DNA The “rods” of the ladder are made up of
other molecules called nitrogen bases Nitrogen bases occur in pairs
Adenine (A)- Thymine (T)Guanine (G) – Cytosine (C)
How does DNA replicate?
Ladder “un-zips” Each side becomes a pattern for the
new DNA strand to build off of New DNA has bases that are identical to
the original DNA
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DNA REPLICATION
GENES DNA contains “instructions” for making
the proteins that determine a person’s characteristics
Gene – section of DNA on a chromosome where the instructions are found
Proteins are composed of amino acids Genes determines the order of the amino
acids Each cell of your body only uses a portion
of the thousands of genes in your DNA
Where are genes found?
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PROTEIN SYNTHESIS Made in the ribosomes of a cell RNA – RiboNucleic Acid
code for making proteins
RNA Structure is similar to ½ of a ladder Ribose - sugar phosphate molecule in
RNA RNA nitrogen bases occur in pairs
Adenine (A) - Uracil (U)Guanine (G) -Cytosine (C)
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TYPES OF RNA
Type Description
Messenger(mRNA)
- Begins protein Synthesis- Provides code that directs sequences for amino acids
Ribosomal(rRNA)
- What Ribosomes are composed of
Transfer(tRNA)
- Serves as the “link” between mRNA and amino acids sequence of
proteins
MUTATIONS Mutation: any permanent change in
the DNA Sequence Occurs when DNA is not copied exactly Examples: extra chromosome, missing a
chromosome X-rays, sunlight, and some chemicals
can also cause mutations
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RESULT OF A MUTATION May or may not be life threatening If mutation occurs in a sex cell, then all
cells that form from that cell will also be mutated
Mutations add variety to speciesSome mutation are harmful, some are
beneficial
What disease is a result of a mutation?
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