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