Section 8.7 Study Guide: Mutations
Vocabulary
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Mutation
Point mutation
Frameshift mutation
Mutagen
Review Questions
1. What is a mutation?
Mutations are changes to an organism’s DNA. The changes may or may not affect the organism’s
phenotype.
2. If a nucleotide is deleted from a strand of DNA, what type of mutation has occurred?
A frameshift mutation
3. List two types of gene mutations.
Point mutation/substitution and frameshift mutation
4. List two types of chromosomal mutations
Gene duplication and translocation
5. Which type of mutation affects more genes, a gene mutation or a chromosomal mutation? Please
explain.
A chromosomal mutation typically affects more genes because it takes place at a chromosomal
level. Chromosomal mutations can have a large effect and may result in a disrupted gene or
abnormal regulation of genes.
6. What leads to gene duplication?
Unequal crossing over between homologous chromosome pairs.
7. What is translocation?
The attachment of a piece of one chromosome to a non-homologous chromosome
8. In a frameshift mutation, what is the “frame” that is being shifted?
This mutation involves the insertion or deletion of a nucleotide in a DNA sequence, which shifts
the entire sequence by one or more nucleotides – throwing off the reading frame.
9. How might a point mutation in a gene affect the resulting protein?
Point mutations may result in premature stop codons or the coding for alternate amino acids,
which may change the proteins that are produced. Changes in proteins can disrupt metabolic
functions.
10. Below is a string of nucleotides. With the string of nucleotides, you are going to 1) use brackets to
indicate the reading frame of the nucleotide sequence; 2) write the nucleotide sequence making a
point mutation; and 3) write the nucleotide sequence again but this time make a frameshift
mutation. Use brackets to indicate how the reading frame would be altered.
Nucleotide sequence: A G G C G T C C A T G A
1. Use brackets to indicate the reading frame.
2. Make a point mutation.
3. Make a frameshift mutation.
11. For a mutation to be passed to an offspring, in what type of cell must it occur?
Germ Cell
12. Can DNA polymerase catch and correct every replication error? Explain
No. There is no system of replication that is perfect and DNA polymerase is not perfect (it is very
good at catching and correcting replication errors but it is not perfect).
13. What is a mutagen?
An agent in the environment that can change DNA.
14. In evolution, how do natural selection and mutation work together to better adapt organisms to
their environment (this is worth two extra credit points)?