Study questions genetics ex. 2
Which of the following statements about human oogenesis is TRUE? It starts at puberty Kryokinesis is symmetrical whereas cytokinesis is not Both A and B Neither A nor B
Kryokinesis is symmetrical whereas cytokinesis is not
It contains a single gene which affects a polygenic trait. It controls all of the variation for a polygenic trait. Both A and B
Neither A nor B
Which of the following statements about heterochromatin is TRUE? it contains most structural genes it is extended and accessible to proteins
Neither A nor B
Which of the following statements is TRUE? Aneuploidy for autosomes is more tolerated than that for sex chromosomes. Polyploidy is more common in animals than in plants. Both A and B Neither A nor B
Neither A nor B
An individual of karyotype 47, + 13 has which of the following syndromes?
Patau
Which of the following cells are diploid? Primary spermatocyte Primordial germ cell Secondary spermatocyte Spermatid Spermatogonium
Primary spermatocyte Primordial germ cell Spermatogonium
Chiasmata are formed during
Prophase I
Consider three genes P, Q and R, that have the following distances in map units: P-Q = 3 m.u; P-R = 7 m.u; and Q-R = 10 m.u. What is the gene order?
Q-P-R
Genes a, b and c are linked on a particular chromosome in this order. The distance between a and b is 9.0 map units, while b and c are 30 map units apart. What is the probability of a double crossover if interference in this chromosomal region is 70%?
0.81%
Refer to the organism of question 22. From the cross Zt/zT X ZT/zt, what is the expected frequency of individuals with zigzag tails in the progeny?
0.20
You perform a particular three-point test cross in Drosophila that produced 1,000 flies. You expect 30 double crossover recombinants, however, you could only detect 24. What is the value for interference?
0.20
In a small animal, P, E and B are found on a chromosome at map positions 5, 25, and 55, respectively. A three-factor cross was performed that yielded 1,000 progeny, including 42 double crossover recombinants. What is the value for interference?
0.30
In a Turner individual, how many unpaired chromosomes are present in metaphase I of meiosis?
1
Genes x, y and z are linked on a particular chromosome in this order. The distance between x and y is 7.5 map units, while y and z are 23.1 map units apart. What is the probability of a double crossover in this chromosomal region? (Assume no interference)
1.73%
The weight of a particular animal is controlled by four genes. Individuals can be 10, 20, 30, 40, 50, 60, 70, 80 or 90 kilograms. What proportion of the offspring of the cross of AabbccDd x aaBbccDd animals are expected to weigh 10 kg?
1/16
The housefly, Musca domestica, has 2n =12. A fly would have _____ chromosomes in metaphase of mitosis; ________ sister chromatids in metaphase I meiosis and ________ chromosomes in prophase II of meiosis.
12; 24; 6
In dragons, straight tails require the presence of either or both of two dominant alleles, Z and T. Individuals homozygous for both recessive alleles have zigzag tails. The two genes are on the same chromosome and recombine with a frequency of 24 percent. From the cross ZT/zt X ZT/zt, what is the expected frequency of individuals with zigzag tail in the progeny?
14.44 %
Assuming a case of polygenic inheritance with additive alleles, where there are seven genes involved, how many phenotypic classes are expected?
15
Consider a plant with 4n = 60. How many chromosomes would be found in a monoploid cell?
15 60/4=15
How many phenotypic classes are expected in the progeny of a FOUR-POINT test cross?
16
A certain type of grass has a diploid chromosome number of 8. A related species of grass has a diploid chromosome number of 10. Interspecific hybridization between the two species results in sterile hybrids. Endoreduplication, however, generates fertile hybrids with a chromosome number of
18
Genes A and B are linked with recombination frequency of 0.2. Both genes segregate dominant (A and B) and recessive alleles (a and b). The parental cross AABB x aabb is performed and then the F1 progeny is testcrossed to aabb. If 10 individuals are counted in the F2, how many are expected to have recombinant phenotypes?
2
A meiotic cell cycle consists of _____ cell division(s) and ____ DNA replication(s).
2 ; 1
In humans, how many chromosomes are present in metaphase II of meiosis?
23
In humans, how many tetrads are present in metaphase I of meiosis?
23
A calico cat mates with an orange cat. What percentage of their offspring is expected to be black?
25%
In a particular animal, genes C and D are unlinked. An animal of genotype C/C D/D is crossed with one of genotype c/c d/d. The F1 animals are then testcrossed. What percent of the F2 generation is expected to be c/c d/d?
25%
Species A and species B are closely related. Both are diploid with A having 2n = 12 and B having 2n = 14. How many chromosomes will an allotetraploid have?
26 12+24=26
The newly-discovered organism Yawle nhoj, has a diploid chromosome number of 56. How many bivalents and tetrads would be expected to form during meiosis?
28 and 28, respectively
In a human, how many different types of gametes are possible? Assume no crossing-over.
2^23
If a normal diploid cell is 2n, the chromosome content of a double tetrasomic cell is designated
2n + 2 + 2
In a particular animal, lung cells have 32 pairs of chromosomes. How many chromosomes does a sperm cell contain?
32
Species A has 2n = 12. How many chromosomes will an autohexaploid have?
36
The organism Sllub adirolfhtuos has 16 pairs of long chromosomes, whereas the organism Scub yabapmat has 20 pairs of short chromosomes. The expected chromosome number in somatic tissues of a hybrid between these two organisms is
36
in a particular animal, horn length is an example of continuous variation, under polygenic control. Horns could be = 1, 3, 5, 7, 9, 11, 13, 15 or 17 centimeters long. How many genes are involved?
4
In a healthy male, 100 primary spermatocytes will form ______ sperm.
400
In a particular animal, gametes contain 20 chromosomes. How many chromosomes would be found in a trisomic body cell? 21 22 41 42
41
A normal human somatic cell has _____ autosomes.
44
Which of the following is the karyotype of an individual with Edwards syndrome?
47, XX, +18
In an animal with 2n = 24, what is the total number of chromatids present at prophase I of meiosis?
48
Which of the following human karyotypes exhibit EUPLOIDY? 69, XXX 47, XX, + 13 45, XO two of the above none of the above
69, XXX
The diploid number of the garden pea is 2n=14. The number of different trisomics that could be formed is
7
A cell contains 18 pairs of chromosomes immediately after completion of mitotic cytokinesis. How many chromatids were present in metaphase?
72
A cell contains 20 chromosomes immediately after completion of telophase of meiosis II. How many chromatids were present in metaphase I?
80
In a plant with 2n = 40, what is the total number of chromatids present at prophase of mitosis?
80
A normal chromosome has the gene sequence A B C D E F G • H I. Which of the following represents a reverse duplication?
A B C D D C B E F G • H I
A normal chromosome has the gene sequence A B C D E F G • H I. Which of the following represents a tandem duplication? (duplication of exons within the same gene)
A B C D E F D E F G • H I
A normal chromosome has the gene sequence A B C D E F G • H I. Which of the following represents a pericentric inversion? A B F G • H I A B C D E F G • I H A D C B E F G • H I A B C D E H • G F I
A B C D E H • G F I
A plant has 2n = 16. Which of the following statements is TRUE?
A gamete from this plant has 8 chromosomes.
Which of the following best describes the polar body?
A nonfunctional cell produced at the same time as an egg.
Consider a eukaryotic organism whose somatic cells possess 40 chromosomes. Which of the following statements is TRUE?
A triploid individual would have 60 chromosomes.
Nondisjunction can occur in meiosis I. meiosis II. mitosis. A and B. A, B and C.
A, B and C.
In a certain plant, branch length is under the control of three genes. Branches can be absent or 1-6 cm long. Which of the following genotypes are possible for branches that are 3 cm? (only heterozygous dominant at this length)
AaBbCc
In dosage compensation: An X chromosome can be inactivated. Gene expression can be increased from a single X chromosome. Gene expression can be reduced from a pair of X chromosomes. Two of the above are possible Correct Answer All of the above are possible
All of the above are possible
In a particular plant, genes A and B are completely linked. A plant of genotype A b/A b is crossed with one of genotype a b/a b. Which of the following is TRUE? All progeny will be phenotypically Ab All progeny will be phenotypically ab The progeny will have a phenotypic ratio of 1 Ab : 1 ab The progeny will have a phenotypic ratio of 3 Ab : 1 ab none of the above
All progeny will be phenotypically Ab
Which of the following statements about chromosomal aberrations is TRUE? duplications and deletions lead to "genetic imbalance" inversions and translocations lead to "position effect" Both A and B
Both A and B
Which of the following statements about euchromatin is TRUE? it replicates earlier during the S phase than heterochromatin it stains lightly by DNA-binding chemicals
Both A and B
Which of the following statements about eukaryotic nuclear DNA packaging is TRUE? the nucleosome fiber has a diameter of 11 nm the solenoid fiber has a diameter of 30 nm Both A and B
Both A and B
Which of the following statements is TRUE about a normal distribution? Equal numbers of individuals are found above and below the mean. The mean is also the most frequent value. Both A and B
Both A and B
it inhibits the formation of spindle fibers. it can be used to induce polyploidy experimentally in plants. Both A and B Neither A nor B
Both A and B
Consider a eukaryotic organism in which the normal diploid number is 10. Which of the following statements is TRUE? A monosomic individual would have 9 chromosomes. A double trisomic individual would have 12 chromosomes. Both A and B. Neither A nor B.
Both A and B.
Assume the amount of DNA in a cell immediately following mitotic cytokinesis is C. The amount of DNA during G1 of interphase would be
C.
In polygenic inheritance, the phenotype of an allele of one gene depends on the action of alleles of other genes.
False
What is the correct order for the stages of the cell cycle?
G1-S-G2-M
The formation of the 30-nm fiber is facilitated by the protein histone ______.
H1
Which of the following histones would you expect to be the LEAST likely conserved throughout evolution?
H1
The linker DNA of a nucleosome is associated with an
H1 monomer.
The core particle in nucleosomes is composed of two molecules each of histones
H2A, H2B, H3 and H4
Which of the following statements about genome sizes is TRUE?
The genome of Escherichia coli consists of about 4.7 x 10^6 base pairs.
Which of the following processes can cause genes to move from one linkage group to another.
Translocations
In polygenic inheritance, genes are typically equivalent in their contributions.
True
Polygenic inheritance gives rise to quantitative traits that vary along a continuum or a gradient.
True
In grasshopers, sex is determined by the
XX/XO chromosome system.
A woman is a carrier for an X-linked recessive disease. Assume non-disjunction of the X chromosomes occurs during meiosis I but meiosis II is normal. She has a son that is ten years old. Which of the following best describes him?
XXY, normal
In chicken, the female has the _____ sex chromosome composition.
ZW (MALES ARE ZZ)
A triple heterozygote (AaBbCc) was mated to a triple recessive (aabbcc). The progeny were as follows: ABC 4 aBC 335 aBc 48 ABc 127 abC 123 AbC 51 Abc 327 abc 5 The allele arrangement in the triple heterozygote must have been
aBC/Abc (highest numbers)
A normal chromosome has the gene sequence A B C D E F G • H I. This chromosome is
acrocentric (near one end of the chromosome)
Assume non-disjunction occurs in meiosis II in oogenesis. If the resulting gametes are fertilized by normal sperm, what types of zygotes can be produced? trisomic disomic monosomic two of the above all of the above
all of the above
Which of the following could NOT be the genome of a virus? single-stranded circular DNA single-stranded linear DNA double-stranded circular DNA double-stranded linear RNA
all of the above could be
Which of the following human karyotypes does not exhibit ANEUPLOIDY? ( the presence of an abnormal number of chromosomes in a cell, ) 49, XXXX, + 21 48, XX, + 13, + 18 45, XO 47, XYY
all of the above exibit aneuploidy
Which of the following statements best defines a linkage group?
all of the genes that are located on the same chromosome
The condition where an organism's chromosomes are derived from two or more different species is called
allopolyploidy
The Barr body is
an inactivated X chromosome.
A human is missing the paternal chromosome 9 and the maternal chromosome 11. The individual is exhibiting
double monosomy
The condition where an organism gains or loses one or more chromosomes but not a complete chromosome set is called
aneuploidy
A human male with 48 chromosomes exhibits
aneuploidy.
Which of the following terms is NOT used to describe the position of the centromere in eukaryotic chromosomes?
anticentric
The terms cis and trans describe the
arrangement of alleles on homologous chromosomes.
The G0 phase occurs
between G1 and S.
Which of the following statements about pseudodominance is TRUE?
caused by deletion of dominant genes so that recessive alleles on homologous chromosomes are expressed.
Which one of the following CANNOT lead to trisomy 21? maternal non-disjunction in meiosis I maternal non-disjunction in meiosis II paternal non-disjunction in meiosis I paternal non-disjunction in meiosis II choose this answer if all of the above can lead to trisomy 21
choose this answer if all of the above can lead to trisomy 21
The DNA in G1 is found as
chromatin.
Which of the following events occurs in meiosis but NOT mitosis? chromatid formation spindle formation chromosome condensation chromosome pairing chromosome movement to poles
chromosome pairing
The Philadelphia chromosome is associated with which of the following cancers?
chronic myelogenous leukemia
In Drosophila, the genes j and r are linked. Parental flies of genotype j+ r+/ j+ r+ and j r/ j r are crossed. What allele arrangement would the F1 flies contain?
cis
The alignment of sister chromatids is mediated by the protein _______.
cohesin
Assume that a cross is made between AaBb and aabb plants, and all of the offspring are either AaBb or aabb. These results are consistent with which of the following circumstances?
complete linkage
A human that possesses the paternal chromosome 9 and the maternal chromosome 9, and is otherwise normal exhibits
disomy (chromosome represented twice)
Recessive genes a, b, c, d, e, and f are closely-aligned in a chromosome, but their order is unknown. Two deletions in the region are examined: one deletion uncovers genes a and e, and the other uncovers genes c and f. Which of the following could NOT be the order of genes?
e c f a b d
A gene distance of 1 cM is
equivalent to 1 % recombination and 1 map unit.
If three Barr bodies are observed in a mammal, the individual must posses
four X chromosomes.
A graph of the number of individuals in each arbitrary phenotypic class for a quantitative trait is called a(n) .
frequency distribution
Centromeres and telomeres are examples of
heterochromatin.
The synaptonemal complex is the nucleoprotein complex that
holds homologous chromosomes together during meiosis
The allotetraploid of question 49 is said to have _______________ chromosome sets.
homeologous
Recombination frequencies
increase with genetic distance
Linkage violates which of the following Mendelian principles?
independent assortment
In Drosophila, a fly is triploid and possesses a sex chromosome complement of XXY. This fly is
intersex.
In nucleosomes, the DNA associated with the core particle
is 146 bp in length.
Which of the following statements about crossing-over is TRUE?
it does not occur in Drosophila melanogaster males.
The complete set of chromosomes of an individual can best be described as
karyotype
The spindle fibers are attached to the centromere at the
kinetochore
The five sub-stages of prophase I are, in order,
leptonema, zygonema, pachynema, diplonema, diakinesis
You may have noticed that people who have red hair usually have freckles too. Which of the following can best describe this phenomenon?
linkage
Quantitative traits that can be counted and expressed in whole numbers are called _______ traits.
meristic
Introns are generally found in genes of higher eukaryotes __________ in the genes of lower eukaryotes.
more commonly than
If a pair of homologous chromosomes undergoes nondisjunction during anaphase I of meiosis, what will be the chromosome number of the four resulting gametes? Assume meiosis II is normal. n-1; n-1; n; n n+1; n-1; n; n n+1; n+1; n; n n+1; n-1; n-1; n n+1; n+1; n-1; n-1
n+1; n+1; n-1; n-1
Crossing over involves the genetic exchange between
non-sister chromatids of homologous chromosomes
Mosaics are most likely caused by
nondisjunction during mitosis.
Genes C and D are linked with a recombination frequency of 0.4. Both genes segregate dominant (C and D) and recessive alleles (c and d). The parental cross CCDD x ccdd is performed and then the F1 progeny is testcrossed to ccdd. If 10 individuals are counted in the F2, how many are expected to be dominant for BOTH genes? 0 1 2 4 Correct Answer none of the above
none of the above
The newly-discovered organism Yawle nhoj, has a diploid chromosome number of 56. Suppose that one of the chromosome pairs fails to disjoin properly during Meiosis I. How many chromosomes will be present in each of the four gametes that result from that meiosis? Assume meiosis II is normal. 12, 12, 16, 16 12, 16, 14, 14 28, 28, 0, 0 28, 0, 14, 14 none of the above
none of the above
Which of the following best describes a human with an XXXY sex chromosome complement? male with three Barr bodies male with one Barr body male with no Barr bodies female with three Barr bodies
none of the above
The weight of a particular animal is controlled by four genes. Individual animals can be 10, 20, 30, 40, 50, 60, 70, 80 or 90 kilograms. Garfield has genotype AABbCcdd, and Pluto has genotype aabbCCDD. Who is heavier? Garfield Pluto Both have the same weight of 30 kg Both have the same weight of 40 kg
none of the above is true
A cross of two Drosophila strains of genotypes z+ t+ and z t produced the following progeny: 126 z+ t+, 133 z t, 15 z+ t, and 18 z t+. What is the frequency of recombination between genes t and z? 9.3% 12.7% 15.2% 18.6% none of these choices
none of these choices
Which of the following is a correct aneuploid designation in humans? 69, XXX 46, XX, +21 45, XX, +18 -21 45, X, -21 none of these choices
none of these choices
The maximum recombination frequency between two genes is 100% 75% 25% 10% Correct Answer none of these choices
none of these choices (50%) CORRECT
The correct order of DNA packaging levels in eukaryotic chromosomes is
nucleosomes - looped domains - heterochromatin
A human fetus missing the two copies of chromosome 1 exhibits
nullisomy
In a three-factor cross, double cross-over recombinants
occur less frequently than any of the single crossovers.
At physiological pH, histone proteins are
positively-charged.
Meiosis I is called the
reductional division.
The 30 nm fibers of a chromosome are attached to a _________ that holds the fibers in large loops.
scaffold
Crit-du-Chat syndrome results from a deletion in the
short arm of chromosome 5.
DNA toposiomerases
supercoil DNA.
A locus is
the position of a gene on a chromosome.
Mendel's second law (independent assortment) can be explained by
the random arrangement of homologous chromosomes at metaphase I of meiosis
In humans, the genome refers
to the haploid set of chromosomes
In the following list, which term is least related to the others? trisomic monosomic triploid aneuploid
triploid
How many breaks does a paracentric inversion require?
two - both in the same chromosome arm
A Robertsonian translocation results from the fusion of
two non-homologous chromosomes.
Mitosis is used for asexual reproduction in unicellular organisms growth and repair in multicellular organisms production of gametes in multicellular organisms two of the above all of the above
two of the above
Which of the following statements about duplications is TRUE? they are usually more harmful than deletions of the same size they may have long term evolutionary advantage in leading to the formation of new genes. they may result from unequal crossing-over two of the above all of the above
two of the above
In Drosophila melanogaster, the wild-type eye color is red. White eyes is a recessive mutation. Which of the following genotypes will exhibit a white eye phenotype?
w w
