Mutations
Mutations
1. Changes in DNA sequences that affect genetic information are known as
a. replications.b. transformations.c. translations.d. mutations.
Mutations
2. The word mutation comes from the Latin word mutare, which means
a. duplicationb. replicationc. to changed. the effect
Mutations
3. Gene mutations that involve changes in one or a few nucleotides are known as
a. point mutations.b. mutagens.c. polyploidy.d. chromosomal mutations.
Mutations
4. A point mutation where one base is changed to a different base in a DNA sequence is called a(n)
a. insertion.b. deletion.c. polyploidy.d. substitution.
Mutations
5. A point mutation where a base is either inserted into or deleted from a DNA sequence is called a(n)
a. substitution mutation.b. frameshift mutation.c. polyploidy mutation.d. mutagen.
Mutations
6. Identify the type of point mutation that has occurred in the mutant sequence.
a. Substitution mutation.b. Frameshift due to an insertionc. Frameshift due to a deletiond. Polyploidy mutation.
A T G C G G A C T G T A…Original sequenceMutant sequence A T G C G A C T G T A…
G
Mutations
7. Identify the type of point mutation that has occurred in the mutant sequence.
a. Substitution mutationb. Frameshift due to an insertionc. Frameshift due to a deletiond. Polyploidy mutation
A T G C G G A C T G T A…Original sequenceMutant sequence A T G C T G A C T G T A…
GT
Mutations
8. Identify the type of point mutation that has occurred in the mutant sequence.
a. substitution mutation.b. frameshift due to an insertionc. Frameshift due to a deletiond. polyploidy mutation.
A T G C G G A C T G T A…Original sequenceMutant sequence A T G T C G G A C T G T A…
T
Mutations
9. Which base of the codon UCA, when substituted, would have the least effect on the amino acid it codes for?
a. U (the first base)b. C (the second base)c. A (the third base)d. There will always be an effect
Mutations
10. Which type of mutation would most likely cause a major change the shape of a protein?
a. Substitution of one nucleotideb. Substitution of two nucleotidesc. Substitution of three nucleotidesd. Insertion of one nucleotide
Remember, insertions and deletions cause frameshifts.
Mutations11. A substitution mutation occurred in the middle of a gene, causing the protein it codes for to become nonfunctional. The affected codon was changed from UAC to UAA. Explain why the protein doesn’t work.UAC codes for the amino acid Tyrosine. UAA codes for a stop codon. Since the mutation occurred in the middle of the gene, the resulting protein would be way too short to function.
Mutations
12. True or False: “All mutations are harmful.”
False
Mutations13. The blue amino acids are hydrophilic (water loving). The yellow amino acids are hydrophobic (water fearing). How might the shape of the membrane protein shown below change if a substitution mutation changes serine (ser) to valine (val)?
Cell membrane
Membrane protein
Glu
Asn
Phe
Gln
Thr
Ser
Lys
Leu
Cys
Asp
Ala
Cys
Val
Mutations13. The blue amino acids are hydrophilic (water loving). The yellow amino acids are hydrophobic (water fearing). How might the shape of the membrane protein shown below change if a substitution mutation changes serine (ser) to valine (val)?
Cell membrane
The protein’s shape may change significantly as valine tries to move towards the oily region of the cell membrane.
Before mutation
After mutation
Glu
Asn
Phe
Gln
Thr
Ser
Lys
Leu
Cys
Asp
Ala
Cys
Val
Glu
Asn
Phe
Gln Thr
val
Lys
Leu
Cys
Asp
Ala
Cys
Val
Mutations
14. List four types of chromosomal mutations.
a. Deletion
b. Duplication
c. Inversion
d. Translocation
Mutations15. A substance that can cause a change in the DNA code of an organism is called a
a. toxin.b. mutagen.c. nitrogenous base.d. nucleotide.
Mutations16. Name a common chemical that is considered a mutagen.
a. Insecticides
b. Cigarette smoke
c. Pollution
d. Heavy metals
Mutations17. Name a common physical mutagen.
a. X-rays
b. Gamma rays
c. Ultraviolet rays
MutationsUse the diagrams below to answer the question.
a. deletion. b. inversion.c. translocation. d. duplication.
18. Mutant 1 is a(n)
“Normal” chromosome
Mutant 1
Mutant 2
MutationsUse the diagrams below to answer the question.
a. deletion. b. inversion.c. translocation. d. duplication.
19. Mutant 2 is a(n)
Mutant 1
Mutant 2
“Normal” chromosome
Mutations20. Give a few examples of harmful mutations.
a. Cystic fibrosis
b. Sickle cell disease
c. Hemophilia
d. Down syndrome
e. Stunted wings
f. Albinism
Mutations21. Give a few examples of beneficial mutations.
a. Pesticide resistance (beneficial for the insect)b. Lactose tolerancec. Stronger bonesd. Ability to be very flexiblee. Ability to sing extremely wellf. Amazing muscles
Myostatin hypertrophy