Download mutations - Pasadena High School

WHAT IS THE RELATIONSHIP BETWEEN AN
ORGANISM’S DNA AND PROTEIN
SPECIFICITY?
a. DNA becomes a specific part of the protein
structure
b. DNA determines the ribosomal RNA sequence
that becomes part of the protein structure
c. DNA determines which RNA molecules are
incorporated into protein molecules
d. DNA determines the amino acid sequence of each
protein.
THE SYNTHESIS OF STRUCTURE X
OCCURRED IN THE:
a.
b.
c.
d.
Nucleus
Cytoplasm
Lysosome
Vacuole
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video clip?
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1.Figure out the mRNA and
amino acid sequence for
the original strand
1.Figure out the mRNA and
amino acid sequence for
the original strand
2.Repeat this for #1-#4.
AUG AUA GCU UAA
Met.-Ile.-Ala.-stop
AUG AUA CCU UAA
Met.-Ile.-Pro.-stop
AUG AUA GCC UAA
Met.-Ile.-Ala.-stop
AUG UAU AGC CUA A
Met.- Tyr.-Ser.-Leu. 
AUG AUA CUU AA
Met.-Ile.-Leu.-
1.Figure out the mRNA and
amino acid sequence for
the original strand
2.Repeat this for #1-#4.
3.Compare the mRNA and
amino acid sequence of
#1-#4 to the original
strand and write down
what you notice!
DNA MUTATIONS:
Mutation - Change in a DNA sequence
that affects genetic information;
error or mistake in copying DNA.
TYPES OF MUTATIONS:
1. Point Mutations - Mutation that affects a single
nucleotide, usually by substituting one nucleotide for
another.
 Substitution – one base is changed to another
Original: AUGUAC → Met – Tyr
Mutated: AUGUAG → Met – Stop
(causes the amino acid chain to stop protein production early)
SILENT Point mutations would NOT
change the protein
TYPES OF MUTATIONS:
2. Frameshift Mutations - Mutation that shifts the “reading”
frame of the genetic message by inserting or deleting a
nucleotide.
–Insertions – A base is inserted into the DNA sequence.
–Deletions - A base is removed from the DNA sequence.
Original: The fat cat ate the wee rat.
Frame Shift: The fat caa tet hew eer at.
(Frame shift mutations affect all subsequent amino acids!)
SIGNIFICANCE OF MUTATIONS:
Many mutations have little or no effect on the
expression of genes.
Mutations may be harmful and may be the cause of
many genetic disorders and cancer.
Source of genetic variability in a species (may be
highly beneficial).
WHAT VARIES IN OUR DNA:
Mutations cause a change in the sequence of the
nitrogen bases (or the order of nucleotides).
This creates differences between organisms (physical or
not) because the DNA sequences are not similar, so the
genes do not code for the same traits!
GENE:
AAGCCTAGCAC =
MUTATED GENE:
AAGCTTAGCAC =
no fingerprint!