BMSC 210- Module 5 And 8-Test
Questions and Answers.
Why are wild type genotypes useful? - Answer They are used as a non-mutated reference
point
Screening tests hundreds/thousands/millions of colonies (select one) - Answer Thousands
What are auxoautotrophs? - Answer Mutants that cannot biosynthesize certain amino acids
What is a spontaneous mutation? - Answer A mutation that arises naturally and not as a result
of exposure to mutagens
What is an induced mutation? - Answer Caused by mutagens
What is a point mutation? - Answer Substitution, deletion, or insertion of a single base pair
What is a silent mutation? - Answer Often a base change in 3rd position of codon, that doesn't
actually effect the amino acid that is coded for (tRNA wobble)
What is a missense mutation? - Answer A point mutation, usually in the first or second
position, that changes the amino acid that is coded for
What is a nonsense mutation? - Answer A point mutation that results in the code being turned
into a stop codon, which then results in an incomplete/truncated protein
What is an indel mutation? - Answer An insertion or deletion
What is a frameshift mutation? - Answer Mutation that shifts the "reading" frame of the
genetic message by inserting or deleting a nucleotide
What is a reversion? - Answer When a second mutation cancels the effect of the first one.
There are several different types of this mutation
Revertant mutation - Answer Type of reversion. When the phenotype is returned to the wild
type
, True revertant mutation - Answer When the genotype is returned to the wild type genotype
Suppressors and types - Answer Suppress mutations
- Can be the same gene, but different location, that still restores protein activity
- Can be on a different gene, that then restores the function of the original gene
- Can be on a different gene that compensates for or replaces the original gene
The error rate for spontaneous mutation is 1 in ___________ - Answer 10 million/s
Nucleotide base analog - Answer Type of mutagen that resembles a nucleotide, and is inserted
during replication. Leads to faulty base paring, and a high error rate at the point of insertion
Chemical modification - Answer Type of mutagen that modifies one of the bases, which results
in faulty base pairing. This mutagen does not require replication to first occur
Intercalating agents - Answer Type of mutagen that inserts between two base pairs, and
induces a frameshift (single base pair insertion or deletion) during replication
What is a non-ionizing mutagen, and it's effects - Answer UV light. It tends to create
pyrimidine dimers, which causes a bump in the DNA, and impedes DNA polymerase, causing a
misreading
What is an ionizing mutagen, and it's effects - Answer X-rays. Creates free radicals, which
damages DNA by creating single and double strand break, which then leads to large deletions
and rearrangements
Ames test - Answer A test which uses auxotrophs to test mutagenic potential
True or false: replication stalls can be lethal - Answer True
SOS repair system - Answer Repairs DNA that has breaks, gaps, or legions, by using a
specialized DNA polymerase to synthesize a new DNA strand, even if there is not a normal
complementary strand to act as a template
RecA - Answer Bacterial recombinase
Transformation - Answer Uptake of foreign DNA from the surrounding environment
Questions and Answers.
Why are wild type genotypes useful? - Answer They are used as a non-mutated reference
point
Screening tests hundreds/thousands/millions of colonies (select one) - Answer Thousands
What are auxoautotrophs? - Answer Mutants that cannot biosynthesize certain amino acids
What is a spontaneous mutation? - Answer A mutation that arises naturally and not as a result
of exposure to mutagens
What is an induced mutation? - Answer Caused by mutagens
What is a point mutation? - Answer Substitution, deletion, or insertion of a single base pair
What is a silent mutation? - Answer Often a base change in 3rd position of codon, that doesn't
actually effect the amino acid that is coded for (tRNA wobble)
What is a missense mutation? - Answer A point mutation, usually in the first or second
position, that changes the amino acid that is coded for
What is a nonsense mutation? - Answer A point mutation that results in the code being turned
into a stop codon, which then results in an incomplete/truncated protein
What is an indel mutation? - Answer An insertion or deletion
What is a frameshift mutation? - Answer Mutation that shifts the "reading" frame of the
genetic message by inserting or deleting a nucleotide
What is a reversion? - Answer When a second mutation cancels the effect of the first one.
There are several different types of this mutation
Revertant mutation - Answer Type of reversion. When the phenotype is returned to the wild
type
, True revertant mutation - Answer When the genotype is returned to the wild type genotype
Suppressors and types - Answer Suppress mutations
- Can be the same gene, but different location, that still restores protein activity
- Can be on a different gene, that then restores the function of the original gene
- Can be on a different gene that compensates for or replaces the original gene
The error rate for spontaneous mutation is 1 in ___________ - Answer 10 million/s
Nucleotide base analog - Answer Type of mutagen that resembles a nucleotide, and is inserted
during replication. Leads to faulty base paring, and a high error rate at the point of insertion
Chemical modification - Answer Type of mutagen that modifies one of the bases, which results
in faulty base pairing. This mutagen does not require replication to first occur
Intercalating agents - Answer Type of mutagen that inserts between two base pairs, and
induces a frameshift (single base pair insertion or deletion) during replication
What is a non-ionizing mutagen, and it's effects - Answer UV light. It tends to create
pyrimidine dimers, which causes a bump in the DNA, and impedes DNA polymerase, causing a
misreading
What is an ionizing mutagen, and it's effects - Answer X-rays. Creates free radicals, which
damages DNA by creating single and double strand break, which then leads to large deletions
and rearrangements
Ames test - Answer A test which uses auxotrophs to test mutagenic potential
True or false: replication stalls can be lethal - Answer True
SOS repair system - Answer Repairs DNA that has breaks, gaps, or legions, by using a
specialized DNA polymerase to synthesize a new DNA strand, even if there is not a normal
complementary strand to act as a template
RecA - Answer Bacterial recombinase
Transformation - Answer Uptake of foreign DNA from the surrounding environment
