BIOL 294
Definition of trisomy.
2n + 1
Definition of monosomy.
2n - 1
Characteristics of DNA transposons.
3% of genome Has transposase gene None are mobile in humans
Characteristics of transformation in bacteria.
A cell can be treated to make it competent to take up DNA from its environment. Bacteria can acquire plasmids from outside the cell. A DNA fragment binds to a receptor site on a competent cell, and one of the strands is admitted into the cell, where it pairs with a homologous sequence in the bacterial genome.
Origin of replication in yeast.
ARS
True or False? A duplication refers only to segments of DNA that are repeated in tandem.
False
Which of the following best describes the function of telomerase at the telomere?
It adds new DNA to the 3' end of the template strand.
Lethality of trisomy.
Usually lethal in humans.
Nonhomologous chromosomes exchange parts.
reciprocal translocation
Which term describes the result of two non homologous chromosomes exchanging pieces?
reciprocal translocation
A type of transposable element that moves via RNA intermediate and reverse transcriptase.
retrotransposon
Protein that protects cohesion of the centromere region from cleavage during meiosis I.
shugoshin
Enzyme that elongates specific repetitive sequences at the ends of linear chromosomes.
telomerase
Refer to nucleosome diagram: What is region 2?
About 160 bp of DNA that wraps twice around the octameric core.
Example of monosomy.
An example in humans is XO.
Example of trisomy.
An example in humans is XXY.
What is the first stage in the sequence of the separation of sister chromatids during mitosis?
As the cell enters the S phase, each chromosome begins not only replication of its DNA but also production of histone and nonhistone proteins. (This occurs before condensation.)
Changes that prevent bacterial growth and reproduction on minimal medium.
Auxotrophic mutations
What is the third stage in the sequence of the separation of sister chromatids during mitosis?
Cohesin is cleaved by the time cells leave metaphase.
Whether a bacterial colony seen in a culture plate is large or small, shiny or dull, round or irregular.
Colony morphology mutations
Characteristics of telomerase.
Contains an RNA molecule complementary to telomere repeats Functions as an enzyme Expressed in germ cells
Refer to nucleosome diagram: What is region 1?
Core made up of a total of eight histone units: two each of H2A, H2B, H3, and H4.
Which mechanism of generating chromosomal rearrangements involves non homologous end-joining (NHEJ)?
DNA breakage
A type of transposable element that moves without an RNA intermediate.
DNA transposon
Characteristics of deletions in heterozygotes.
Del/+ genotype A loss-of-function mutation may result in loss-of-heterozygosity May have a mutant phenotype if a mutant allele is uncovered Small, single gene deletions are usually viable Mutant phenotypes may arise due to haploinsufficiency
Characteristics of deletions in homozygotes.
Del/Del genotype Large, Multigene deletions are almost always lethal Small, single gene deletions are often viable
Consider a normal chromosome with the following gene sequence along its length: F G H I J K L. Which of the following sequences represents inversion?
F K J I H G L
A fluorescent DNA probe hybridizes to chromosomal DNA on a slide to located a sequence in the genome.
FISH
The table shows three related species of potato, and the number of chromosome each species carries in its somatic cells. S. avilesii is diploid. S. tuberosum is the widely cultivated species. Potatoes propagate by asexual reproduction and do not depend only on gametes for reproduction. Solanum avilesii: 24 Solanum microdontum: 36 Solanum tuberosum: 48 True or False? Gametes produced by S. microdontum contain 18 chromosomes.
False
The table shows three related species of potato, and the number of chromosome each species carries in its somatic cells. S. avilesii is diploid. S. tuberosum is the widely cultivated species. Potatoes propagate by asexual reproduction and do not depend only on gametes for reproduction. Solanum avilesii: 24 Solanum microdontum: 36 Solanum tuberosum: 48 True or False? S. microdontum could have arisen ONLY from a cross between S. avilesii and S. tuberosum.
False
The table shows three related species of potato, and the number of chromosome each species carries in its somatic cells. S. avilesii is diploid. S. tuberosum is the widely cultivated species. Potatoes propagate by asexual reproduction and do not depend only on gametes for reproduction. Solanum avilesii: 24 Solanum microdontum: 36 Solanum tuberosum: 48 True or False? S. microdontum is aneuploid.
False
The table shows three related species of potato, and the number of chromosome each species carries in its somatic cells. S. avilesii is diploid. S. tuberosum is the widely cultivated species. Potatoes propagate by asexual reproduction and do not depend only on gametes for reproduction. Solanum avilesii: 24 Solanum microdontum: 36 Solanum tuberosum: 48 True or False? The basic chromosome number (x) for these species is 6.
False
True or False? Comparison of the location of DNA transposons in humans shows that some have moved recently.
False
True or False? Condensins decondense chromosomes after mitosis.
False
True or False? DNA reached maximum compaction during prophase.
False
True or False? DNA transposons require an RNA intermediate to move to a new location.
False
True or False? Formation of loops is thought to result in a fiber about 100 Å wide.
False
True or False? In a nucleosome, DNA wraps in a smooth coil drouth the core histones.
False
True or False? Investigators have a complete understanding of the features of higher-order chromosome packing.
False
True or False? Most duplications are lethal in heterozygotes.
False
True or False? The ends of retrotransposons are inverted repeats of each other.
False
True or False? Transposable elements are only found in Zea mays (corn).
False
True or False? Unequal crossing-over in duplication in heterozygotes changes the duplication copy number.
False
True or False? When a DNA transposon moves, a copy always remains in the original location.
False
Mammalian cell types that typically contain a Barr body.
Female skin cells Female blood cells
Regions of a chromosome that are distinguished by staining differences when treated with Giemsa stain.
G bands
Refer to nucleosome diagram: What is region 3?
H1 histone that associates with DNA as it enters and leaves the nucleosome.
In humans. a condition in which a male carries two or more X chromosome in addition to the Y chromosome.
Klinefelter syndrome
Refer to nucleosome diagram: What is region 4?
Linker DNA of about 20 bp. Linkers extend from both ends of the nucleosome and connect with other nucleosomes.
Changes that prevent bacterial cells from breaking down complex chemicals in the environment.
Metabolic mutations
Mutations in genes with crucial protein products; often studied only as conditional lethals.
Mutations in essential genes
Suppose a company develops a chemical that increases telomerase activity. Would this chemical be a suitable candidate for cancer treatment?
No, because increasing telomerase activity will increase cells' ability to grow indefinitely.
Definition of aneuploid.
Not having an exact multiple of the haploid number of chromosomes.
Characteristics of SINEs.
RNA intermediate 13% of genome Contains poly-A Few are mobile in humans
Characteristics of LINEs.
RNA intermediate 20% of genome Contains poly-A Few are mobile in humans
Characteristics of HERVs.
RNA intermediate 8% of genome Contains LTRs None are mobile in humans
Characteristics of conjugation in bacteria.
Requires a special plasmid, such as the F plasmid in E. coli, for DNA transfer. A bacterium that contains an F plasmid connects to a recipient bacterium that lacks an F plasmid with an appendage called a pills, through which the plasmid is transferred. Some DNA from the donor cell's chromosome made have become incorporated into the F plasmid and is transferred to the recipient cell.
Mutations that allow a bacterium to grow in the presence of a bacterial agent, such as a bacteriophage or antibiotic.
Resistance mutations
A reciprocal translocation occurring near the centromere of two Afrocentric chromosomes, producing one large metacentric chromosome and a very small chromosome that may be lost.
Robertsonian translocation
What is the second stage in the sequence of the separation of sister chromatids during mitosis?
The arms and centromeres of the replicated sister chromatid are held together by cohesion.
What is the fourth stage in the sequence of the separation of sister chromatids during mitosis?
The cohesion holding together the centromeres of the sister chromatids is cleaved, and the chromatids are moved to opposite poles.
A promoter in a genome is a DNase-resistant site. Which of the following events could convert the site to a DNase hypersensitive site?
The level of a transcription factor that binds a nearby enhancer increases. A remodeling complex uses ATP to move nucleosomes to expose the promoter. A histone acetyltransferase modifies histone tails in the vicinity of the promoter.
You identify a protein that colocalizes with DNA in mouse cells in culture. You find that the protein is present during all stages of the cell cycle along the length of all chromosomes. Which of the following functions of this protein are likely based on this information?
The protein could be a histone. The protein could be a part of the scaffold.
The table shows three related species of potato, and the number of chromosome each species carries in its somatic cells. S. avilesii is diploid. S. tuberosum is the widely cultivated species. Potatoes propagate by asexual reproduction and do not depend only on gametes for reproduction. Solanum avilesii: 24 Solanum microdontum: 36 Solanum tuberosum: 48 True or False? S. microdontum could have arisen from a cross between S. avilesii and S. tuberosum.
True
The table shows three related species of potato, and the number of chromosome each species carries in its somatic cells. S. avilesii is diploid. S. tuberosum is the widely cultivated species. Potatoes propagate by asexual reproduction and do not depend only on gametes for reproduction. Solanum avilesii: 24 Solanum microdontum: 36 Solanum tuberosum: 48 True or False? S. microdontum is a triploid with 3x chromosomes.
True
The table shows three related species of potato, and the number of chromosome each species carries in its somatic cells. S. avilesii is diploid. S. tuberosum is the widely cultivated species. Potatoes propagate by asexual reproduction and do not depend only on gametes for reproduction. Solanum avilesii: 24 Solanum microdontum: 36 Solanum tuberosum: 48 True or False? S. tuberosum is a tetraploid with 4x chromosomes.
True
The table shows three related species of potato, and the number of chromosome each species carries in its somatic cells. S. avilesii is diploid. S. tuberosum is the widely cultivated species. Potatoes propagate by asexual reproduction and do not depend only on gametes for reproduction. Solanum avilesii: 24 Solanum microdontum: 36 Solanum tuberosum: 48 True or False? S. tuberosum is likely to be a larger, more vigorous plant than S. avilesii.
True
The table shows three related species of potato, and the number of chromosome each species carries in its somatic cells. S. avilesii is diploid. S. tuberosum is the widely cultivated species. Potatoes propagate by asexual reproduction and do not depend only on gametes for reproduction. Solanum avilesii: 24 Solanum microdontum: 36 Solanum tuberosum: 48 True or False? The basic chromosome number (x) for these species is 12.
True
True or False? Barbara McClintock's primary work on transposable elements was done in Zea mays (corn).
True
True or False? Condensins form chromatin loops attached to the scaffold.
True
True or False? DNA reaches maximum compaction during metaphase.
True
True or False? DNA transposons have inverted repeats at the ends.
True
True or False? DNA wrapped around core histones in a nucleosome exhibits sharp bends as well as unbent regions.
True
True or False? Formation of chromatin loops results in DNA supercoiling that is relaxed by DNA topoisomerase II.
True
True or False? Human LTR retrotransposons are similar in structure to retroviruses.
True
True or False? Nearly 50% of the human genome is made up of transposable elements.
True
True or False? Packaging into nucleosomes condenses DNA approximately 7-fold.
True
True or False? Retrotransposons move via reverse transcription of an RNA intermediate.
True
True or False? Some TEs have a known function; others are characterized a "selfish" DNA.
True
True or False? Some duplication heterozygotes have visible mutant phenotypes because genes at the breakpoints have altered expression.
True
True or False? Some duplication heterozygotes have visible mutant phenotypes because some traits are sensitive to gene dosage.
True
True or False? Transposable elements (TEs) are small segments of DNA that can move from one position to another in a genome.
True
True or False? Two copies of a duplication can be arranged with their base pair sequences in the same order or reverse order.
True
In humans, a condition in which a female has only a single X chromosome.
Turner syndrome
Lethality of aneuploid.
Usually lethal in humans.
Lethality of monosomy.
Usually lethal in humans.
An artificial chromosome created by combining centromeres, telomeres, and origins or replication from yeast.
YAC
Having a chromosome number that is not an exact multiple of the haploid number.
aneuploid
Complexes of DNA and protein located in the eukaryotic nucleus.
chromatin
A gene for antibiotic resistance is flanked on either end by inverted repeats (IRs). Transposase recognizes the IRs and the resistance gene jumps to a new strain of bacteria. This is an example of a...
composite transposon
Removal of a segment of DNA.
deletion
An increase in the number of copies of a chromosomal region.
duplication
An organism that has a mosaic combination of male and female tissue.
gynadromorph
A 180 degree rotation of a chromosomal segment.
inversion
A specialized structure composed of DNA and proteins that is the site at which chromosomes attach to the spindle fibers.
kinetochore
A bread-like structure consisting of DNA wound around histone proteins.
nucleosome
An inversion that excludes the centromere.
paracentric
An inversion that includes the centromere.
pericentric
Having three or more complete sets of chromosomes.
polyploid
A short DNA segment moves from one position in the genome to another.
transposition
