Questions and Answers of Structural Analysis

In eukaryotes, RNA primers are primarily removed bya. DNA polymerase I.b. DNA polymerase α.c. flap endonuclease.d. helicase.
To synthesize DNA, what does telomerase use as a template?a. It uses the DNA in the 3′ overhang region.b. It uses RNA that is a component of telomerase.c. No template is used.d. Both a and b are
The complementarity of DNA strands is based ona. the chemical properties of a phosphodiester linkage.b. the binding of proteins to the DNA.c. the AT/GC rule.d. none of the above.
The origin of replication in E. coli containsa. an AT-rich region.b. DnaA boxes.c. GATC methylation sites.d. all of the above.
In the lagging strand, DNA is made in the direction _________ the replication fork and is made as __________.a. toward, one continuous strandb. away from, one continuous strandc. toward, Okazaki
The proofreading function of DNA polymerase involves the recognition of a ________ and the removal of a short segment of DNA in the __________ direction.a. missing base, 5′ to 3′b. base pair
Which of the following statements regarding DNA polymerases in eukaryotes is not correct?a. DNA polymerase α synthesizes a short RNA-DNA primer.b. DNA polymerases ε and δ synthesize most of the
A site in a chromosome where DNA replication begins isa. a promoter.b. an origin of replication.c. an operator.d. a replication fork.
The enzyme known as ________ uses ________ and separates the DNA strands at the replication fork.a. helicase, ATPb. helicase, GTPc. topoisomerase, ATPd. topoisomerase, GTP
DNA polymerase III is a processive enzyme, which means thata. it does not dissociate from the template strand after it has attached a nucleotide to the 3′ end.b. it makes a new strand very
In eukaryotes, DNA replication is initiated at an origin of replication bya. DnaA proteins.b. the origin recognition complex.c. DNA polymerase δ.d. MCM helicase.
DNA gyrasea. promotes negative supercoiling.b. relaxes positive supercoils.c. cuts DNA strands as part of its function.d. does all of the above.
According to the selfish DNA hypothesis, TEs exist becausea. they offer the host a selective advantage.b. they have characteristics that allow them to multiply within the chromosomal DNA of living
A chromosome territory is a regiona. along a chromosome where many genes are clustered.b. along a chromosome where the nucleosomes are close together.c. in a cell nucleus where a single chromosome is
Negative supercoiling can enhance transcription and DNA replication because ita. allows the binding of proteins in the major groove.b. promotes DNA strand separation.c. makes the DNA more compact.d.
The function of transposase isa. to recognize inverted repeats.b. to remove a TE from its original site.c. to insert a TE into a new site.d. all of the above.
In Noll’s experiment to test the beads-on-a-string model, exposure of nuclei from rat liver cells to a low concentration of DNase I resulted ina. a single band of DNA with a size of approximately
The role of cohesin is toa. make chromosomes more compact.b. allow for the replication of chromosomes.c. hold sister chromatids together.d. promote the separation of sister chromatids.
A bacterial chromosome typically containsa. a few thousand genes.b. one origin of replication.c. some repetitive sequences.d. all of the above.
Mechanisms that make the bacterial chromosome more compact includea. the formation of microdomains and macrodomains.b. DNA supercoiling.c. crossing over.d. both a and b.
The chromosomes of eukaryotes typically containa. a few hundred to several thousand different genes.b. multiple origins of replication.c. a centromere.d. telomeres at their ends.e. all of the above.
Which of the following are moderately repetitive sequences?a. Genes that encode rRNAb. Most protein-encoding genesc. Both a and bd. None of the above
Which of the following types of transposable elements rely on an RNA intermediate for transposition?a. Insertion elementsc. Retrotransposonsb. Simple transposonsd. All of the above
What are the components of a single nucleosome?a. About 146 bp of DNA and four core histone proteinsb. About 146 bp of DNA and eight core histone proteinsc. About 200 bp of DNA and four core histone
The compaction leading to a metaphase chromosome involves which of the following?a. The formation of nucleosomesb. The formation of the 30-nm fiberc. The further compaction of the loop domainsd. All
A key difference between the nucleotides found in DNA and those in RNA is thata. those in DNA have phosphate, and those in RNA do not.b. those in DNA have deoxyribose, and those in RNA have ribose.c.
Chargaff’s analysis of the base composition of DNA is consistent with base pairing betweena. A and G, and T and C.b. A and A, G and G, T and T, and C and C.c. A and T, and G and C.d. A and C, and T
A groove in a DNA double helix refers toa. the indentations where the bases are in contact with the surrounding water.b. the interactions between bases in the DNA.c. the spiral structure of the
A key difference between B DNA and Z DNA is thata. B DNA is right-handed, whereas Z DNA is left-handed.b. B DNA obeys the AT/GC rule, whereas Z DNA does not.c. Z DNA allows ribose in its structure,
In the experiment of Avery, McLeod, and McCarty, the addition of RNase or protease to a DNA extracta. prevented the conversion of type S bacteria into type R bacteria.b. allowed the conversion of
Going from simple to complex, which of the following is the proper order for the structure of DNA?a. Nucleotide, double helix, DNA strand, chromosomeb. Nucleotide, chromosome, double helix, DNA
Which of the following could be the components of a single nucleotide found in DNA?a. Deoxyribose, adenine, and thymineb. Ribose, phosphate, and cytosinec. Deoxyribose, phosphate, and thymined.
In a DNA strand, a phosphate connects a 3′ carbon atom in one deoxyribose toa. a 5′ carbon in an adjacent deoxyribose.b. a 3′ carbon in an adjacent deoxyribose.c. a base in an adjacent
Evidence that led to the discovery of the DNA double helix includeda. the determination of structures using ball-and-stick models.b. the X-ray diffraction data of Franklin.c. the base composition
Which of the following is not a feature of the DNA double helix?a. It obeys the AT/GC rule.b. The DNA strands are antiparallel.c. The structure is stabilized by base stacking.d. All of the above are
A double-stranded region of RNAa. forms a helical structure.b. obeys the AU/GC rule.c. may result in the formation of a structure such as a bulge loop or a stem-loop.d. does all of the above.
Humans with aneuploidy who survive usually have incorrect numbers of chromosome 13, 18, or 21 or the sex chromosomes.A possible explanation why these abnormalities permit survival is becausea. the
Staining eukaryotic chromosomes is useful because it makes it possible toa. distinguish chromosomes that are similar in size and centromeric locations.b. identify changes in chromosome structure.c.
A mechanism that can produce a translocation isa. the joining of reactive ends when two different chromosomes break.b. crossing over between nonhomologous chromosomes.c. crossing over between
Due to crossing over within an inversion loop, a heterozygote with a pericentric inversion may produce gametes that carrya. a deletion.b. a duplication.c. a translocation.d. both a deletion and a
With regard to gene duplications, which of the following statement(s) is/are correct?a. Gene duplications may be caused by nonallelic homologous recombination.b. Large gene duplications are more
The somatic cells of an allotetraploid containa. one set of chromosomes from four different species.b. two sets of chromosomes from two different species.c. four sets of chromosomes from one
In agriculture, an advantage of triploidy in plants is that the plants area. more fertile.b. often seedless.c. always disease-resistant.d. all of the above.
A chromosome that is metacentric has its centromerea. at the very tip.b. near one end, but not at the very tip.c. near the middle.d. at two distinct locations.
In a person with trisomy 21 (Down syndrome), a genetic imbalance occurs becausea. genes on chromosome 21 are overexpressed.b. genes on chromosome 21 are underexpressed.c. genes on the other
A paracentric inversiona. includes the centromere within the inverted region.b. does not include the centromere within the inverted region.c. has two adjacent inverted regions.d. is an inverted
Humans have 23 chromosomes per set. A person with 45 chromosomes can be described as beinga. euploid.c. monoploid.b. aneuploid.d. trisomic.
A bacterial cell with an F factor conjugates with an F− cell.Following conjugation, the two cells will bea. F+.b. F−.c. one F+ and one F−.d. none of the above.
What is the correct order for the steps of transformation given in the following list?Recombination with the bacterial chromosome 2.Binding of a large DNA fragment to the surface of a bacterial cell
A change in chromosome structure that does not involve a change in the total amount of genetic material isa. a deletion.b. a duplication.c. an inversion.d. none of the above.
The term endopolyploidy refers to the phenomenon of havinga. too many chromosomes.b. extra chromosomes inside the cell nucleus.c. extra sets of chromosomes in certain cells of the body.d. extra sets
In a diploid species, complete nondisjunction during meiosis I may produce a viable cell that isa. trisomic.b. haploid.c. diploid.d. triploid.
Which of the following statements is correct?a. If a deletion and a duplication are the same size, the deletion is more likely to be harmful.b. If a deletion and a duplication are the same size, the
During transduction involving a P1 phage,a. any small fragment of the bacterial chromosome may be transferred to another bacterium by a new phage.b. only a specific fragment of DNA may be transferred
Which of the following is a type of plasmid?a. F factor (fertility factor)b. R factor (resistance plasmid)c. Virulence plasmidsd. All of the above are types of plasmids.
Some bacterial species preferentially take up DNA fragments from members of their own species. This uptake can be promoted bya. competence-stimulating peptide (CSP).b. DNA uptake signal sequences.c.
In mapping experiments, ______ strains are conjugated to F−strains. The distance between two genes is determined by comparing their ________________ during a conjugation experiment.a. F+, times of
A form of genetic transfer that involves the uptake of a fragment of DNA from the environment is calleda. conjugation.b. transduction.c. transformation.d. all of the above.
With regard to conjugation, a key difference between F+ and Hfr cells is that an Hfr cella. is unable to conjugate.b. transfers a plasmid to the recipient cell.c. transfers a portion of the bacterial
Which of the following is an example of horizontal gene transfer?a. The transfer of a gene from one strain of E. coli to a different strain via conjugationb. The transfer of a gene from one strain of
For a chi square test involving genes that may be linked, which of the following statements is correct?a. An independent assortment hypothesis is not proposed because the data usually suggest
What is the map distance between the two genes for eye color and wing length?a. 32.3 mub. 34.5 muc. 16.2 mud. 17.3 mu
In the experiment by Bateson and Punnett, which of the following observations suggested genetic linkage in the sweet pea?a. A 9:3:3:1 ratio was observed in the F2 offspring.b. A 9:3:3:1 ratio was not
Morgan observed a higher number of recombinant offspring involving eye color and wing length (401 + 318) than those involving body color and eye color (17 + 12). These results occurred becausea. the
The recombinant offspring of the F2 generation were due to crossing over that occurreda. during spermatogenesis in the P generation males.b. during oogenesis in the P generation females.c. during
One yeast strain carries the alleles lys+ and arg+, whereas another strain has lys-3 and arg-2. The two strains were crossed to each other, and an ascus obtained from this cross has four spores with
Genetic linkage occurs becausea. genes that are on the same chromosome may affect the same character.b. genes that are close together on the same chromosome tend to be transmitted together to
With regard to linked genes on the same chromosome, which of the following statements is false?a. Crossing over is needed to produce nonrecombinant offspring.b. Crossing over is needed to produce
What is/are the phenotype(s) of the recombinant offspring of the F2 generation?a. red eyes, long wingsb. white eyes, miniature wingsc. red eyes, long wings and white eyes, miniature wingsd. red eyes,
A tetrad of spores in an ascus is the product ofa. one meiotic division.b. two meiotic divisions.c. one meiotic division followed by one mitotic division.d. one mitotic division followed by one
The process of mitotic recombination involves thea. exchange of chromosomal regions between homologs during gamete formation.b. exchange of chromosomal regions between homologs during the division of
A female born with Angelman syndrome carries a deletion in the AS gene (i.e., the UBE3A gene). Which parent transmitted the deletion to her?a. Her fatherc. Either her mother or fatherb. Her mother
Chloroplasts and mitochondria evolved from an endosymbiotic relationship involvinga. purple bacteria and cyanobacteria, respectively.b. cyanobacteria and purple bacteria, respectively.c.
Which of the following is not a phase of XCI?a. Nucleationb. Spreadingc. Maintenanced. Erasure
The marking process for genomic imprinting initially occurs duringa. gametogenesis.c. embryonic development.b. fertilization.d. adulthood.
Some human diseases are caused by mutations in mitochondrial genes. Which of the following statements is false?a. Human mitochondrial diseases follow a maternal inheritance pattern.b. Mutations
What is the explanation for maternal effect at the molecular and cellular levels?a. The father’s gene is silenced at fertilization.b. During oogenesis, nurse cells transfer gene products to the
According to the Lyon hypothesis,a. one of the X chromosomes is converted to a Barr body in somatic cells of female mammals.b. one of the X chromosomes is converted to a Barr body in all cells of
A female mouse that is Igf 2 Igf 2− is crossed to a male that is also Igf 2 Igf 2−. The expected outcome for the phenotypes of the offspring for this cross isa. all normal size.c. 1 normal size :
A cross is made between a green four-o’clock plant and a variegated one. If the variegated plant provides the pollen, the expected outcome of the phenotypes of the offspring will bea. all plants
A female snail that coils to the left has offspring that coil to the right. What are the genotypes of this mother and of the maternal grandmother of the offspring, respectively?a. dd, DDb. Dd, Ddc.
In fruit flies, dosage compensation is achieved bya. X-chromosome inactivation.b. doubling the expression of genes on the single X chromosome in the male.c. halving the expression of genes on each X
In mice, the copy of the Igf 2 gene that is inherited from the mother is never expressed in her offspring. This happens because the Igf 2 gene from the mothera. always undergoes a mutation that
Extranuclear inheritance occurs due toa. chromosomes that have become detached from the spindle apparatus during meiosis.b. genetic material that is found in chloroplasts and mitochondria.c.
Dominant alleles may result from a mutation that causesa. the overexpression of a gene or its protein product.b. production of a protein that inhibits the function of a normal protein.c. a protein to
A person with type AB blood has a child with a person with type O blood. What are the possible blood types of the child?a. A or Bb. A, B, or Oc. A, B, AB, or Od. O only
Hemophilia is a blood-clotting disorder in humans that follows an X-linked recessive pattern of inheritance. A man with hemophilia and a woman without hemophilia have a daughter with hemophilia. If
If the F1 offspring from question 1 are allowed to self-fertilize, what is the expected outcome for the F2 offspring?a. All whiteb. All purplec. 3 purple : 1 whited. 9 purple : 7 white
Polydactyly is a condition in which a person has extra fingers and/or toes. It is caused by a dominant allele. If a person carries this allele but does not have any extra fingers or toes, this is an
Which of the following statements is true?a. Not all inheritance patterns follow a strict dominant/recessive relationship.b. Geneticists want to understand both inheritance patterns and the
Which of the following phenotypes is not an example of a wildtype phenotype?a. Yellow-flowered elderflower orchidb. Red-flowered elderflower orchidc. A gray elephantd. An albino (white) elephant
The outcome of an individual’s traits is controlled bya. genes.b. the environment.c. both genes and the environment.d. neither genes nor the environment.
A pink-flowered four-o’clock is crossed to a red-flowered plant.What is the expected outcome for the offspring’s phenotypes?a. All pinkb. All redc. 1 red : 2 pink : 1 whited. 1 red : 1 pink
A cross is made between a white-eyed female fruit fly and a redeyed male. What would be the reciprocal cross?a. Female is XwXw and male is XwY.b. Female is Xw+Xw+ and male is Xw+Y.c. Female is Xw+Xw+
A cow with scurs and a bull with no scurs have an offspring. This offspring could bea. a female with scurs or a male with scurs.b. a female with no scurs or a male with scurs.c. a female with scurs
The Manx phenotype in cats is caused by a dominant allele that is lethal in the homozygous state. A Manx cat is crossed to a normal (non-Manx) cat. What is the expected outcome for the surviving
Which of the following is a possible explanation for pleiotropy?a. The expression of a single gene can affect cell function in more than one way.b. A gene may be expressed in different cell types in
Two different strains of sweet peas are true-breeding and have white flowers. When plants of these two strains are crossed, the F1 offspring all have purple flowers. This outcome is due toa.
An abnormal fruit fly has two sets of autosomes and is XXY. Such a fly isa. a male.c. a hermaphrodite.b. a female.d. none of the abo
In mammals, sex is determined bya. the SRY gene on the Y chromosome.b. having two copies of the X chromosome.c. having one copy of the X chromosome.d. both a and c.

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