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Genetics Review
Mrs.Paparella
Spring 2010
DNA
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Hereditary information stored in nucleus
Makes up genes which make up chromosomes
Is made up of nucleotide subunits
Each subunit has 3 things
Phosphate
Sugar
Nitrogen base: AT GC
• Has a double helix shape
Explain what this diagram means!
Nucleus
chromosome
Genes
DNA
DNA Controls Cell Activities
the main one is protein synthesis
• Determines order of amino acids in proteins
• Those proteins are used as enzymes to make
reactions in your body happen (digestion,
synthesis)
• Enzymes regulate chemical reactions
• Proteins make up hormones(Insulin, estrogen,
testosterone)
• Proteins make up antibodies
Protein Synthesis
• http://www.biostudio.com/case_freeman_protei
n_synthesis.html
• DNA in nucleus untwists and then mRNA
(messenger RNA) moves out of the nucleus and
travels through the cytoplasm to the ribosome
where the protein will get made
• tRNA(transfer RNA) will bring specific amino acids
to the mRNA and those a.a. will join together to
make a specific protein that was coded for by the
order of the ATGC’s in the original DNA strand.
Protein Synthesis
DNA in nucleus unwinds and makes a template
mRNA gets made
Moves out of nucleus to cytoplasm
mRNA travels to the ribosome
tRNA transfers the specific amino acid
to the mRNA strand
The specific protein will get made
The genes in the DNA coded for this specific
protein; the instructions are in the code
The order of the ATGC’s of the gene determine
the protein that gets made
Mutations in the gene sequence
• Any change in the normal DNA sequence (order of the
ATTCGGA etc. ) is called a mutation
• A base unit can be substituted or deleted which may
affect what amino acid gets brought to the mRNA on
the ribosome.
• For example if the normal gene code is:
ATT-GCG- AAA-CCC• If that first A is deleted, then the code would read:
TTG-CGA-AAC-CC which might bring the wrong amino
acid and then the wrong protein would get made
which wouldn’t work properly as a certain enzyme.
Causes of Mutations
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Exposure to radiation: UV radiation, X-rays
Exposure to chemicals
Viruses
Random changes during meiosis (crossing
over)
Mutations are random
• Some are not that big a
deal
• Others can make a
protein malfunction and
cause major diseases
like sickle cell anemia
which is a blood cell
disorder. The Red Blood
cells are not round, they
are deformed in shape.
How does the disease get passed on?
More Details about Sickle Cell Disease
• http://sites.google.com/site/geneticdisorders7
/sickle-cell-anemia
DNA and Individual
Cell types
• Every single cell in your body has a complete set
of identical genetic instructions in its nucleus
• So, why are there so many different kinds of
cells?
• Each cell only uses a small part of the instructions
that it needs to operate properly.
• Certain genes get switched off and on as they are
needed.
• Internal (inside the body) and external(outside)
factors can switch those genes off and on. We call
that activation of genes.
Expression of Genes
• Temperature can determine which gene gets
expressed in the Himalayan Rabbit.
• Black fur will grow when
the body area is cold.
When the body area is warm,
white fur will grow.
Why are the ears, nose and
Feet black?
The Arctic Hare in Winter and in Summer
Genetic Engineering
• Technology that humans use to alter the
genetic information in organisms
• Genetically Modified Fruits, Vegetables and
Animals are created by genetic engineers who
select certain gene sequences that will make
specific varieties of those species.
• It involves using special enzymes that cut DNA
segments in certain spots so that new
organisms can be made that do certain things.
www.pbs.org/wgbh/aso/tryit/dna/#
Science Review Games: www.sciencereviewgames.com
Genes & Chromosomes
Discusses gene chromosome theory, gene linkage
and inheritance.
Genetic Disorders & Mutations
Reasons for the following mutations are
discussed: PKU, tay-sachs, sickle-cell anemia,
and down's syndrome.
History & Technology of Genetics
Basic overview of the technologies and the
history within the genetic field.
Population Genetics
Reviews: gene pool, mutation, migrations, gene
frequencies, population genetics and geographic
isolation.
Punnet Square
Practice with Punnet Squares.
RNA & Protein Synthesis
Components of RNA and protein synthesis.