Biology - Types & Effects of Genetic Mutations

A type of point mutation that alters the length of the DNA strand is _____. •A deletion. •A transition. •A base substitution •An transversion.

A deletion.

An example of a transversion mutation is _____. •A cytosine substituted for a thymine. •A guanine substituted for a thymine. •A thymine substituted a cytosine. •An adenine substituted for a guanine.

A guanine substituted for a thymine.

The best term to describe the incorporation of a random mistake into the DNA sequence at a specific point is _____.

A point mutation

Which of the following modifications of this DNA sequence, ACTGAC, would be considered a frameshift mutation? •ACCTGAC •AGTGAC •ACTGAT •ACAGAC

ACCTGAC

Based on the original sequence, ACTTGAC, which of the following answer choices includes a transition mutation? •ACTTCAC •ACTTTAC •ACTTGTC •ACTTGGC

ACTTGGC

_____ is used to describe a mutation in which one nitrogenous base is replaced by another.

Base substitution

How do mutagens cause mutations?

By increasing the likelihood of a replication error

Which enzyme checks DNA for errors?

DNA polymerase

What are mutations that result in DNA sequences that are slightly too long or too short called?

Frameshift mutation

_____ mutations result in a longer DNA strand.

Insertion

Which type of mutations can result in a frameshift?

Insertions and deletions

The eleventh amino acid of protein X should be serine, however, due to a mutation it now has the amino acid alanine in that position. Which type of mutation could have caused this change?

Missense

The deletion of a base in the DNA strand will _____.

Result in the deletion of a base in the mRNA strand and a modification to the subsequent amino acid.

In point mutations, there are changes in one or a few nucleotides at a single location in a DNA sequence. Which of the following is NOT a nucleotide? •Thymine •Adenine •Guanine •Ribose

Ribose

Part of a normal DNA sequence is TACCGG. If this sequence undergoes a base substitution, out of the possibilities given identify the sequence that could be a possible result. •TACGG •TACCGG •TACCGGA •TACAGG

TACAGG

How are the Tay Sachs and the Duchenne Muscular Dystrophy diseases different?

Tay Sachs is caused by insertion of a nucleotide base into the hexosaminidase gene while the Duchenne Muscular Dystrophy is caused by deletion of a nucleotide base from the dystrophin gene.

How does a frameshift mutation in the gene coding for the enzyme, hexosaminidase A, result in Tay-Sachs disease?

The mutation results in incorrect synthesis of the enzyme.

How would a shift in the reading frame likely alter the resulting protein?

The protein would be greatly altered because multiple amino acids would be miscoded.

Why do people try to protect their skin from ultraviolet radiation?

UV radiation is a mutagen.

When can a genetic mutation get passed down through successive generations?

When it doesn't cause significant harm to the organism's ability to survive and reproduce

Mutagens are typically found _____.

in an organism's environment

A mutation in DNA can affect the amino acid sequence because it affects the code found in _____.

mRNA

What kind of mutation causes sickle-cell anemia?

missense

Which type of mutation results in an incomplete polypeptide because of an early stop signal?

nonsense

Which type of mutation does NOT change the overall function of the protein?

silent