Download Activity Apr 20, 2016 – 6.3 Genetic Mutation

SBI 4UI
1.
Genetics Mutations
Read section 6.3 pages 262 to 265 and explain the following terms into your notes.
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2.
Mutation
Single-gene mutations
Chromosome mutations
Point mutations
Frame-shift mutations
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Silent mutations
Missense mutations
Nonsense mutations
Physical mutagens
Chemical mutagens
Use the following base sequence on a strand of a DNA molecule.
3’-A A T A C A A T G C C A G T G G T T C G C A C A T T C G– 5’
a) Give the base sequence of the complementary strand of DNA for the above strand of
DNA.
b) Give the base sequence of the mRNA strand for the above TEMPLATE strand of DNA.
c) Write the protein fragment that the mRNA strand in (b) above would code for.
d) If the 4th nucleotide from the left in the mRNA strand above were changed from U to C,
what mutation is this and what would the resulting mRNA look like?
e) Write the protein fragment that the mRNA strand in (d) above would code for.
g) If a G were added to the mRNA strand between the 3rd and 4th nucleotides from the left,
what mutation is this and what would the resulting mRNA look like?
h)
Write the protein fragment that the mRNA strand in #6 above would code for
i) If the 8th nucleotide from the left in the mRNA strand above were changed from G to C,
what mutation is this and what would the resulting mRNA look like?
j)
Write the protein fragment that the mRNA strand in #8 above would code for.
SBI 4UI
Genetics Mutations
Answers
Read section 6.3 pages 262 to 265 and explain the following terms into your notes.
1.





2.
Mutation
Change in the genetic code
Single-gene mutations
Changes in one gene
Chromosome mutations
Changes in many genes
Point mutations
Changes one base pair in code
Frame-shift mutations
Changes entire sequence of code
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Silent mutations
Does not change the gene expression
Missense mutations
Does change the gene expression
Nonsense mutations
Changes code to a stop codon
Physical mutagens
Physically alter the code (ie radiation)
Chemical mutagens
Chemically alter the code (ie drugs)
Use the following base sequence on a strand of a DNA molecule.
3’-A A T A C A A T G C C A G T G G T T C G C A C A T T C G– 5’
f) Give the base sequence of the complementary strand of DNA for the above strand of
DNA.
5’- TT ATG TTA CGG TCA CCA AGC GTG TAA GC- 3’
g) Give the base sequence of the mRNA strand for the above TEMPLATE strand of DNA.
Template DNA 3’-AA TAC AAT GCC AGT GGT TCG CAC ATT CG– 5’
mRNA
5’ -AUG UUA CGG UCA CCA AGC GUG UAA -3’
h) Write the protein fragment that the mRNA strand in (b) above would code for.
MET-LEU-ARG-SER-PRO-SER-VAL
i)
If the 4th nucleotide from the left in the mRNA strand above were changed from U to C,
what mutation is this and what would the resulting mRNA look like?
mRNA
5’ -AUG CUA CGG UCA CCA AGC GUG UAA -3’
Silent Mutation
j)
Write the protein fragment that the mRNA strand in (d) above would code for.
MET-LEU-ARG-SER-PRO-SER-VAL
g) If a G were added to the mRNA strand between the 3rd and 4th nucleotides from the left,
what mutation is this and what would the resulting mRNA look like?
mRNA
5’ -AUG GUU ACG GUC ACC AAG CGU GUA A -3’
Frameshift Mutation
h)
Write the protein fragment that the mRNA strand in #6 above would code for
MET-VAL-THR-VAL-THR-LYS-ARG-VAL
i) If the 8th nucleotide from the left in the mRNA strand above were changed from G to C,
what mutation is this and what would the resulting mRNA look like?
mRNA
5’ -AUG UUA CCG UCA CCA AGC GUG UAA -3’
Missence Mutation
j)
Write the protein fragment that the mRNA strand in #8 above would code for.
MET-LEU-PRO-SER-PRO-SER-VAL