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NAME ______________________________________ PERIOD__________________ DATE_________
Genetic Mutations Practice
Background Information:
Mutations are changes in genetic material (DNA). Mutations occur in 1 in every 1 billion base pairs. This
computes to everyone having an average of 6 mutations in each cell in their body. Mutations are not always
seen and the affected gene may even still function. Mutations can be harmful, beneficial, or have no effect
on the organism. They are a major source of genetic variation in a population and increase biodiversity.
Mutations are only passed on to the offspring if they occur in the gametes (egg and sperm). Mutations that
occur in body cells only affect the organism in which they occur and are not passed onto offspring.
Point mutations occur when the one base sequence of a codon is changed. These mutations can result in
codons having nitrogen bases being added, deleted, or exchanged. There are 3 types of point mutations:
Substitution mutations, deletion mutation, and insertion mutations.
Mutations can be caused naturally by simply a mistake as the DNA is being copied, or through an
environmental events. Environmental events that cause mutations are called mutagens. Examples of
mutagens are x-rays, chemicals, UV light, and radiation.
Directions:
Use the information above, your notes, and your text book to answer the following questions.
1. Define mutation. _____________________________________________________________________
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2. What happens to the DNA code in a gene mutation? _________________________________________
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3. What affect do mutations have on an organism? ____________________________________________
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4. How do mutations affect a population? ___________________________________________________
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5. How are mutations inherited? ___________________________________________________________
6. What mutations are not inherited? _______________________________________________________
7. What is a point mutation? ______________________________________________________________
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NAME ______________________________________ PERIOD__________________ DATE_________
Background Information
Use the normal DNA, mRNA, tRNA, and amino acids to determine the type and severity of the following mutations.
Use the notes from the DNA mutation PPT.
Normal DNA:
Normal mRNA:
Normal tRNA:
Normal Amino Acid
–
–
–
–
GTA
CAU
GUA
Histidine
AGG
UCC
AGG
Serine
–
–
–
–
TAG
AUC
UAG
Isoleucine
–
–
–
–
CAT
GUA
CAU
Valine
–
–
–
GCC
CGG
GCC
Arginine
PROCEDURE
Transcribe and translate the following segment of DNA into the correct amino acids. Group your mRNA and tRNA
into triplets to help you find the amino acid easier.
MUTATION #1
MUTATED
DNA:
mRNA:
–
GTA
Amino Acid
–
AGG
–
TAC
–
CAT
–
–
–
–
–
–
–
–
GCC
1. What is the name of the mutation? ______________________________________________________________
2. How did this mutation affect the amino acids that were made (compared to the normal amino acids)? Explain your
answer. ___________________________________________________________________________________
_________________________________________________________________________________________
MUTATION #2
MUTATED
DNA:
mRNA:
–
GTA
Amino Acid
–
AGG
–
TGC
–
ATG
–
–
–
–
–
–
–
–
CC
3. What is the name of the mutation? ______________________________________________________________
4. How did this mutation affect the amino acids that were made (compared to the normal amino acids)? Explain your
answer. ___________________________________________________________________________________
_________________________________________________________________________________________
MUTATION #3
MUTATED
DNA:
mRNA:
Amino Acid
GTA
–
AGG
–
TAG
–
GCA
–
–
–
–
–
–
–
–
–
TGC
C
5. What is the name of the mutation? ______________________________________________________________
6. How did this mutation affect the amino acids that were made (compared to the normal amino acids)? Explain your
answer.
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Conclusion: Which of the above point mutations are considered to be the most dangerous and why?
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