BIOLOGY CHAPTER 14 LEARNING CURVE QUESTIONS
The amount of new mutations in living organisms following a round of genome replication:
generally increases with larger genomes.
Sites in the genome that are more susceptible to mutations are called:
hotspots
Which of the following would you expect to have the lowest nucleotide mutation rate?
humans
_____ is the process where new genes evolve from duplicates of old ones.
Duplication and divergence
Which of the following statements is true of a chromosome inversion?
-An inversion usually results from breakages in non-coding DNA. -An inversion results in the "flipping" of certain chromosomal segments. -Inversions can alter the order of genes within a chromosome. -Inversions are not always fatal for an organism.
Genetic risk factors:
-can increase the likelihood of somatic mutations. -can increase the likelihood of germ-line mutations. -can work synergistically with environmental risk factors. -can be heritable.
When comparing DNA sequences of similar genes for proteins in related species, you see that some of the sequences are longer in one species compared to the other. Which of the following would most likely represent the extra number of bases that you would see?
21
Which of the following enzymes is responsible for initiating certain types of base excision repair?
DNA uracil glycosylase
A trinucleotide of 5'CTC3' or 5'TTC3' is transcribed and then translated into the amino acid glutamic acid. A trinucleotide of 5'CAA3' or 5'TAC3' is transcribed and then translated into valine. In sickle-cell hemoglobin, valine is present instead of glutamic acid. Assuming a single base pair substitution has occurred, what is the mRNA code for valine in the affected mutant?
GUA
Which of the following statements is true concerning the work of the Esther and Joshua Lederberg?
Their work relied on a technique of bacterial culture known as "replica-plating," and demonstrated that mutations occur randomly within organisms.
Which of the following statements concerning cancer and mutations is correct?
Usually multiple mutations are required in different genes to cause cancer.
Mutation rates (of nucleotides):
are highest in viruses.
The rates of evolutionary change in DNA:
are highly variable among different gene families.
What is one reason that RNA viruses and retroviruses have such a high rate of mutation?
because RNA is more fragile than DNA and because viral polymerases lack a proofreading mechanism.
Chromosomal aberrations:
can be caused by errors during cell division.
DNA repair:
can involve excision of bases flanking a distortion in the helix.
Mutations:
can leave the protein sequence intact.
You are working in a lab studying a gene and notice that there are many other genes that code for similar traits. This is most likely the result of:
duplication and divergence.
A researcher has carried out Giesma staining on a set of human chromosomes, and has arranged these chromosomes into a karyotype. She notices that in a homologous pair, a band is missing from one of the chromosomes. This likely resulted from:
either a deletion or a reciprocal translocation.
Any DNA "damage" is considered to be a mutation, even if it is immediately correct by the action of DNA polymerase.
false
Any deviation in normal gene dosage is lethal.
false
Consider a polyploid plant that has several copies of each of its genes. This plant will likely die prematurely, given this high gene dosage.
false
DNA ligase is responsible for repairing thymine dimers caused by UV light.
false
Duplication and divergence
false
In base excision repair, a whole segment of DNA is removed and resynthesized.
false
Mutations will always decrease the activity of a gene.
false
Spontaneous mutations that occur in somatic cells will be transmitted to offspring.
false
The use of antibiotics is creating the mutations in bacteria that make them resistant to these antibiotics.
false
Which of the following mutations would most likely have the most severe consequence?
frameshift
A chromosomal mutation where a segment breaks off, flips, and then reattaches itself is called a(n):
inversion
Sickle-cell anemia is an example of what type of mutation?
missense
The GAG codon, which codes for glutamic acid, is mutated to GUG, which now codes for valine. What type of mutation is this?
missense
A point mutation that now codes for the wrong amino acid is called a:
missense mutation
The fact that humans have a relatively large number of mutations per genome per generation when compared to other organisms can be explained by:
most of a human's DNA is noncoding, so most of the mutations are neutral.
Chronic myelogenous leukemia (CML) is caused when a segment of chromosome 9 and a segment of chromosome 22 both break off and switch places. How is this mutation classified?
reciprocal translocation
Which of the following would best describe the results seen in a flower whose sectors have different pigmentation?
the result of transposable elements
A chromosomal segment that breaks off and inserts into another chromosome is what type of mutation?
translocation
Normally in corn, genes for waxy and virescent kernel appearance are linked. In a certain stock, however, it was found that these two genes assort independently. Which chromosomal aberration would explain this?
translocation
A chromosomal mutation in which a segment (not containing a centromere) is missing is called a deletion.
true
A point mutation is when a single nucleotide gets replaced by a different one.
true
Dosage refers to the number of copies of each gene in a chromosome.
true
Even though the chance of a mutation for one given nucleotide is rare, mutations are rather common when looking at the whole genome.
true
Generally speaking, a nucleotide substitution has less severe consequences than a nucleotide addition/deletion.
true
Insertion of one nucleotide in a gene will lead to a frameshift mutation.
true
Movable DNA sequences that can "jump" from one spot in the genome to another are called transposable elements.
true
Mutagens increase the amount of damage to DNA.
true
Only germ line mutations are transmitted to the progeny.
true
