Station 10
2D Describe the relationships between
changes in DNA and potential
appearance of new traits including
 Alterations during replication
 Insertions
 Deletions
 Substitutions
 Mutagenic factors that can alter
DNA
5’ AUGUCGCAA 3’ 5’ AUAUCGCAA 3’
5’ AGCGUCUAG 3’  5’ AGCGUCUAU 3’
5’ GUGCGAUUU 3’  5’ GUGGGAUUU 3’
5’ ACGGCUACC 3’  5’ ACGGGUACC 3’
A A A A A A
A A A A U U
U U U U G G
G G G G C C
C C C C C C
C G U A
Changes to the Genetic Code
1.
Arrange the colored letters in the order shown below. Note that the letters are arranged
in groups of three which represent a codon.
Determine the name of the amino acid each codon represents using the mRNA Genetic
Code chart. Write the name of the amino acids on your student answer sheet.
2. Genetic mutations are often caused by changes in the bases of the codons. Compare the
sequence of codons above to the sequence below and find the change that has occurred in one
of the codons.
What amino acid has been changed? What is the new amino acid? This type of mutation is
called a point mutation. One base changed but resulted in a different amino acid. Write the new
codon arrangement on your answer sheet and identify the amino acid sequence.
3. Using the original codon sequence in question 1, add one additional cytosine before the second
codon, GCG. Now shift the remainder of the bases into new codon groups of three bases. You
will have one base left over at the end. How have the amino acids changed from the original
sequence? This is called a frame-shift mutation known as insertion. Write the new codon
arrangement on your answer sheet and identify the amino acid sequence.
4. Using the original codon sequence in question 1, remove a base from the first codon, AUG.
Rearrange the bases into new codons with three bases for each codon. How have the amino
acids changed from the original sequence? This is a frame-shift mutation know as deletion.
Write the new codon arrangement on your answer sheet and identify the amino acid sequence.
Sickle cell anemia is the result
of a point mutation, a change in
just one amino acid in the gene
for hemoglobin. The mutation
causes red blood cells to become
rigid and sickle-shaped, which
can lead to lung tissue damage,
pain episodes, stroke and
damage to most organs including the spleen, kidneys
and liver. Symptoms can range from mild to severe,
and there is currently no cure available.
Duchenne Muscular
Dystrophy results from
a mutation caused by the
deletion of DNA bases
that lead to errors in the
translation and loss of
the production of the
dystrophin protein.
The lack of dystrophin,
An important protein in skeletal muscles, leads to
severe muscle weakness and eventually death.
Huntington's disease is a disorder in which nerve cells
in certain parts of the brain waste away, or degenerate.
A CAG repeat occurs many more times than it is
supposed to. Normally, this section of DNA is
repeated 10 to 28 times.
Strawberries that are Polyploid have multiple sets of
chromosomes. Mutations such as this have positive
effects and are not harmful.
Alpha1 Antitrypsin Deficiency is caused by a single
point mutation that results in rare form of emphysema
in adults and a rare form of liver disease (cirrhosis) in
children and adults. The liver does not make enough of
a protein that protects the lungs and liver from damage
Cystic Fibrosis is a
disease that causes
thick, sticky mucus
to form in the
lungs, pancreas
and other organs. In the lungs, mucus blocks airways,
causing lung damage and making it hard to breathe. In
the pancreas, it clogs the pathways leading to the
digestive system, interfering with proper digestion.
The disorder is caused by the deletion of three bases
which prevents phenylalanine in the cell membrane.
Tay-Sachs disease is a
rare disorder that results
in the destruction of
nerve cells in the brain
and spinal cord. The
disorder is caused by an
addition of base pairs
that alter the coding of
the mRNA sequence and
causes problems in
lysosomes, the waste
processing centers of the
cell.
Polyploidy in orchids result in larger flowers. This
type of orchid has twice the number of chromosomes
as found in other orchids.