bill 211 exam 2 multiple choice

What is an adaptive mutation? Give an example. A mutation that gives advantage in certain environments (is not not "revealed" in all environments), allows for organism with the mutation to survive and reproduce (to be better adapted to the environment), and occurs independent of the environment. (The environment DOES NOT cause the mutation!!! Rather it selects for the persistence of the mutation in the population.)

A mutation that gives advantage in certain environments (is not not "revealed" in all environments), allows for organism with the mutation to survive and reproduce (to be better adapted to the environment), and occurs independent of the environment. (The environment DOES NOT cause the mutation!!! Rather it selects for the persistence of the mutation in the population.)

The addition of a single nucleotide to the DNA sequence causes a frameshift mutation. A) True B) False

A) True

A mutation that changes a single nucleotide can result in a different amino acid being added into a protein. A) True B)False

A) True

DNA mutations are passed on to a cell's progeny. A) True B)False

A) True

In a frameshift mutation, all of the amino acids before the shift are changed. A) True B) False

B) False

The nucleic acid sequence in mRNA is determined by A) the order of amino acids in the protein B) nucleotide sequence in DNA C) nucleotide sequence in t-RNA D) all of the above

B) nucleotide sequence in DNA

3. A nucleotide deletion in DNA replication A) causes one amino acid of the protein to be incorrect B) causes all of the amino acids of the protein to be incorrect C) causes the amino acids inserted after the deletion to be incorrect D) causes the amino acids inserted before the deletion to be incorrect E) has no effect on the resulting protein

C) causes the amino acids inserted after the deletion to be incorrect

If a frameshift mutation causes a stop codon to be inserted into the DNA sequence A) the resulting protein will not be affected B) the phenotype will change but not the genotype C) the resulting protein will be too short and non-functional D) the resulting protein will be too long and non-functional

C) the resulting protein will be too short and non-functional

Which one of the following statements is false. A. A silent mutation or a missense mutation may not affect the activity of a protein but a frameshift mutation always will affect the activity of a protein. B. A silent mutation result in enhanced activity of a protein. C. A missense mutation may result in enhanced activity of a protein D. Insertion of a transposon into a coding region of a gene will always lead to an inactive protein.

C. A missense mutation may result in enhanced activity of a protein

Why does a frameshift mutation in a coding region of a generally lead to a shortened (truncated) polypeptide?

because a frameshift mutation generates a stop codon which stops the polypeptide chain from continuing to grow

DNA polymerases I and III have proofreading ability but still mistakes in base pairing are nor corrected 100% of the time. Is there an advantage for the process not to be 100% effective?

no, unless there's already an existing mutation and doesn't read it

Organism X has suffered a mutation in its DNA, yet its phenotype is unchanged. Explain in 2-3 sentences or less.

It has most likely gone through a silent mutation which initially has no effect on the outcome or the mutation was not in the codon region

109 E. coli cells are plated onto TSA agar containing 100ug/ml of the antibiotic streptomycin. After incubation, 50 colonies are found growing on the agar surface. These colonies are mutants that are resistant to streptomycin. Did the presence of streptomycin in the agar cause the mutation to streptomycin resistance? Explain.

No, because streptomycin is an antibiotic and antibiotics can not cause mutations just selects for it.

Could an adaptive mutation be the result of a Silent mutation? Missense mutation? Nonsense mutation? Frameshift mutation? Insertion of a transposon?

Silent mutation? no Missense mutation? yes Nonsense mutation yes Frameshift mutation? yes Insertion of a transposon? yes