4.2 Mutation
Name: _________________
1. Given the normal DNA sequence ACTGGTACTGTTA, identify each of the following an
addition, deletion, or substitution of a base.
Base Sequence
Addition, deletion, or substitution
ACTGCTACTGTTA
Substitution
ACTGGTACTGTT
Deletion
ACTGGGTACTGTTA
Addition
2. What are the three different effects a mutation can have on an individual? Give an
example of each.
Effect
Positive
Negative
Neutral
Example
Viral/Fungal resistance
(Plants, Humans/HIV)
Sickle Cell Anemia
White Spirit Bear
3. Why is the white coat colour of the Spirit Bear considered to be a neutral mutation?
The white coat colour of the Spirit bear is considered to be a neutral mutation because it neither
harms the bear nor gives the bear a survival advantage.
4. Explain the purpose of gene therapy and order the steps of the process.
Purpose
To correct mutations.
Summary of Steps
2
The healthy gene is delivered to a cell in an inactivated virus.
1
Researchers determine which gene is mutated and causes the
disease.
4
The functioning protein is used in the cell.
3
The cell starts copying the healthy gene.
Science 9 ● Biology● Assignment
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5. What can happen when a mutated gene makes a protein that doesn’t function properly?
Provide an example.
Result
Example
If a gene produces a protein that does not function properly, this
may cause disease.
Sickle cell anemia and cystic
fibrosis.
6. Mutations to DNA cause changes in organisms. Explain why this might be important to
the survival of a species.
Mutations are important to the survival of a species because, if conditions in the environment change,
entire populations of individuals could be wiped out. For example, a virus that spreads very quickly
in an organism may affect some individuals differently depending on genetics.
7. Predict whether a mutation in a human skin cell that results in cancer can be passed on
to an offspring. Explain.
Prediction
No
Explanation
A mutation in a skin cell will only affect the individual. Genetic information can
only be passed on to the next generation by sperm and egg cells.
Science 9 ● Biology● Assignment
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8. Complete the following table regarding sickle cell anemia.
Draw an Affected Cell
Drawing will vary
Is the mutation positive, neutral or
Negative
negative?
How does this mutation affect individuals that have this mutation?
Individuals do not receive enough oxygen because it cannot be carried
efficiently and blockages in blood vessels might occur, which could
cause organ damage.
Some individuals living in Africa have this mutation, but may be less likely to contract the
potentially fatal disease malaria. Does this change the overall effect of this mutation for these
individuals?
Yes. Mutations can be both positive in one way and negative in another.
9. Explain why sun tanning can be dangerous for a skin cell?
During sun tanning, skin cells are exposed to ultraviolet light (ie. radiation). This causes mutation and
possible skin cancer.
10. Why should proper protection always be used when handling chemicals?
Some chemicals are mutagens and can cause mutations. Protection helps prevent our DNA from
being changed.
11. How can viruses cause mutations?
Viruses can cause mutations by attaching to DNA, which will cause the gene to be misread or copied
incorrectly.
Science 9 ● Biology● Assignment
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