Question: The single-celled yeast, Saccharomyces cerevisiae, was used to construct the first eukaryotic artificial chromosome. This was a significant achievement because
Answer Options:
• A) yeast centromeres are identical to human centromeres.
• B) it defined chromosomal regions that serve as centromeres and origins of replication in yeast.
• C) it revealed the rate of DNA replication in yeast.
• D) it demonstrated that some yeast genes are not essential.
• E) it defined the chromosomal region with the TRP+ gene for tryptophan synthesis in yeast.
Answer: B) it defined chromosomal regions that serve as centromeres and origins of replication in yeast.
Question: Which sequence of elements represents a complete yeast artificial chromosome (YAC) that is most likely to replicate and segregate correctly?
Answer Options:
• A) telomere — ARS — centromere
• B) telomere — ARS — centromere — 100,000 bp insert
• C) telomere — centromere — 100,000 bp insert — telomere
• D) telomere — ARS — centromere — 11,000 bp insert — telomere — suitable selectable markers
• E) telomere — ARS — centromere — 100,000 bp insert — telomere
Answer: D) telomere — ARS — centromere — 11,000 bp insert — telomere — suitable selectable markers
Question: Sites of transcription and therefore most of the genes along the length of the chromosome appear to be found in
Answer Options:
• A) heterochromatin.
• B) euchromatin.
• C) constitutive heterochromatin.
• D) centromeric regions.
Answer: B) euchromatin
Question: When a chromosomal rearrangement, such as an inversion, places a known gene into or next to a heterochromatic region, the gene’s transcription
Answer Options:
• A) will turn on.
• B) may be amplified.
• C) may cease.
• D) may be inverted.
Answer: C) may cease.
Question: Position-effect variegation of red and white eye color in Drosophila produces
Answer Options:
• A) one red eye and one white eye.
• B) two red or two white eyes depending on which gene is dominant.
• C) eyes alternating red and white eye facets.
• D) eyes with red and white patches of varying sizes and positions.
Answer: D) eyes with red and white patches of varying sizes and positions.
Question: In which of the following cases will a Barr body be seen?
Answer Options:
• A) only XX
• B) XY
• C) XO
• D) only XXY
• E) both XX and XXY
Answer: E) both XX and XXY
Question: During development, an XX human female embryo will condense one of the X chromosomes in each cell into a Barr body. This usually occurs
Answer Options:
• A) at the 500–1000 cell stage, about two weeks after zygote formation.
• B) by the end of the first trimester.
• C) at the 16-cell stage.
• D) in the X that has the most recessive alleles.
Answer: A) at the 500–1000 cell stage, about two weeks after zygote formation.
Question: FISH analysis is useful for determining the
Answer Options:
• A) order of DNA fragments in a BAC.
• B) pattern of expression of a cloned gene.
• C) chromosomal location of a gene.
• D) map order of two closely linked genes.
Answer: C) chromosomal location of a gene.
Question: You treat a sample of chromatin with DNase and run the digested fragments out on an electrophoretic gel. You find mostly long DNA fragments. What can you conclude about this sample of chromatin?
Answer Options:
• A) The sample contains mostly euchromatin.
• B) The sample contains relatively few histone proteins.
• C) The sample contains mostly heterochromatin.
• D) The DNA is from yeast cells.
• E) The sample likely represents actively transcribed genes.
Answer: C) The sample contains mostly heterochromatin.
Question: You are studying a histone complex that contains an unusually high level of modification with acetyl groups. What can you conclude about the DNA bound to this histone complex?
Answer Options:
• A) It contains actively transcribed genes.
• B) It is most likely heterochromatin.
• C) It is most likely telomeric.
• D) It is most likely derived from a condensed Barr body.
Answer: A) It contains actively transcribed genes.
Question: Which of the following predictions could you make about a cell in which the HP1 protein was disabled?
Answer Options:
• A) Methylation of DNA would increase.
• B) All of the cell’s chromosomes would be completely condensed into heterochromatin.
• C) Histone methyltransferase would bind to chromatin more easily.
• D) Heterochromatin would not be formed.
Answer: D) Heterochromatin would not be formed.
Question: Which of the following is a predicted consequence of kinetochores not achieving the correct level of tension from the mitotic spindle?
Answer Options:
• A) Sister chromatids will no longer be held together at their centromeres.
• B) All chromosomes will migrate to one pole instead of to two opposite poles.
• C) Mitosis will not progress beyond metaphase.
• D) No prediction can be made.
Answer: C) Mitosis will not progress beyond metaphase.