Eukaryotic cells differ from prokaryotic cells in that
B. only eukaryotes have a true nucleus.
An allele is
C. a form of a gene.
If two chromosomes of a species are the same length and have similar centromere placement
but are not homologous, then
A. one chromosome might be metacentric while the other one might be acrocentic
B. one is maternally inherited while the other is paternally inherited
C. the chromosomes contain the same set of genes
D. none of the above
If a typical diploid somatic cell of an organism has 64 chromosomes, how many chromosomes are
expected in each gamete of that organism?
C. 32
If a G1 somatic cell nucleus in a Myrmecia pilosula contains 2 picograms of DNA, how much DNA
would be expected in a gamete from this organism?
D. 1 picogram
Karyotypes are made using chromosomes at which stage of mitosis?
D. Metaphase
During spermatogenesis in an animal species with a normal haploid number of 6, one tetrad
undergoes nondisjunction during the first meiotic division. Following the second meiotic division,
how many of the four gametes produced should contain only 5 chromosomes?
B. 2
The synaptonemal complex
B. forms during prophase I of meiosis
For an organism of genotype Aa, half of its gametes contain only the A allele and half contain only
the a allele. This is essentially Mendel's law of
A. segregation
Pigeons may exhibit a checkered or plain color pattern. When checkered pigeons were crossed
with plain pigeons, 38 F1 offspring were produced and they were all checkered. When the checkered
F1 offspring were crossed, 28 checkered and 9 plain offspring were produced. From this data, the
simplest conclusion is
B. Checkered is dominant to plain.
A recessive allele in tigers causes the white tiger. Two normally pigmented tigers are mated and
produce a white offspring. If the two adult tigers produce a second offspring, what is the probability
that it will have normal pigmentation?
D. 75%
In each one of Mendel's dihybrid crosses,
B. simple dominance and recessiveness were seen.
In a cross AaBbCc x AaBBcc, where capital letters refer to dominant alleles, what is the
probability of producing an offspring that has a dominant phenotype for all three characteristics?
D. 3/8
A 9:3:3:1 ratio of phenotypes in the F2 generation of a dihybrid cross
A. indicates that the dihybrid cross is basically equivalent to two independent monohybrid
crosses.
In corn, purple kernels are dominant over yellow kernels and full kernels are dominant over
shrunken kernels. A true-breeding plant with purple, full kernels is crossed with a plant with yellow,
shrunken kernels. The F1 plants have purple, full kernels. In the F2 generation, what proportion of
the plants would be expected to have purple, shrunken kernels?
B. 3/16
In a cross between two plants of the following genotypes: (AaBb x AaBb), which one of the
following genotypes should occur in 1/8 of the offspring?
B. AABb
If an individual has the genotype AaBbCCDD and all four genes assort independently, how
many different types of gametes should that individual produce with respect to the four genes?
B. 4
Each of the following statements about meiosis is true EXCEPT
A. the products of meiosis are haploid.
B. most somatic cells do not enter into meiosis.
C. during meiosis, crossing-over often occurs between non-homologous chromosomes.
D. the complete process of meiosis requires two rounds of cell division.
C. during meiosis, crossing-over often occurs between non-homologous chromosomes.
In terms of genetic content,
A. sister chromatids are identical right after DNA replication
In animals, how many functional eggs are generally produced from one complete round of
meiosis in a female?
A. one
For the pedigree below, the condition depicted is
A. autosomal dominant
Consider the following pedigree for a very rare trait (in second and third generations of males not infecting parents and kids but across the family tree)
D. sex-linked recessive
Red-green color blindness is X-linked recessive. A color-blind woman has a child with a man
having normal vision. Which phenotype is definitely NOT expected for the child?
A. color-blind female
Consider a gene with alleles A and a. Suppose that the homozygous recessive genotype aa is
lethal during embryonic development. Consider two other genes, B and C that assort independently
from gene A and have no interactions with gene A. In a cross between two individuals, AaBbCc x
AaBbCC, what percentage of the offspring should die during embryonic development?
C. 1/4
A healthy man ("John") has a brother who has cystic fibrosis. John's parents are healthy. What
is the probability that Johns' brother is homozygous for the cystic fibrosis allele?
D. 100% -- He's homozygous since we're told that the disease is recessive
What is probability that John from question 25 is heterozygous for the cystic fibrosis allele?
C. 2/3
What is the probability that John's mother is heterozygous for the cystic fibrosis allele?
D. 100%
A condition in which one gene influences the phenotypic expression of another gene is called
D. epistasis
The trait of medium-sized leaves in iris is determined by the genotype PP'. Plants with large
leaves are PP, whereas plants with small leaves are P'P'. A cross is made between two plants each
with medium-sized leaves. If they produce 80 offspring, what would be the expected number of
offspring having medium sized leaves?
B. 40
The trait of leaf-size in iris, as described in question 29 above, is an example of:
C. partial dominance
For the cross AaBb x AaBb, if the genes assort independently, what fraction of the offspring
would you expect to have the genotype A-bb where the hyphen can be either the dominant (A) or
recessive (a) allele?
B. 3/16
In a disputed parentage case, the child is blood type O (not Bombay) while the mother is blood
type B. What blood type would exclude a male from being the father?
D. AB
With which of the following would hemizygosity most likely be associated?
C. X-linked inheritance
If a gene is subject to genomic imprinting, then
B. one inherited allele, either the maternal or paternal, is expressed while the other is silenced.
Two fruit flies that are wingless are crossed, and it is discovered that all of their offspring have
wings. This is an example of
A. complementation
For the two parent flies in question 35 above, the genetic mutations in the two flies
B. are in two different genes
Which statement is true?
A. two genes on different chromosomes will assort independently from one another.
Which phenotype pair represents the "parental" or noncrossover type of offspring? (figure 1)
B. pair B
Which phenotype pair represents the "double-crossover" type of offspring? (figure 1)
C. pair C
Which two genes are the farthest apart on the chromosome? (figure 1)
A. black & curved
In humans, the genetic basis for determining the sex "male" is accomplished by
C. the presence of the SRY gene
The genotype XYY produces a
C. male in Drosophila and a male in humans.
A somatic cell from a tetraploid person contains a total of how many chromosomes?
B. 92
A balanced translocation
A. leads to the condition of "semisterility" even in the absence of any crossing-over.
If an organism is heterozygous for a chromosomal inversion, then
C. meiotic crossovers within the inverted interval will not be recovered in offspring.
Familial Down syndrome is caused by:
D. a Robertsonian translocation.
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