Exam 3
CSS/Hort 430/530
2008
1) In a hermaphroditic plant that shows maternal inheritance of organelle genomes you expect to see
a) autosomal patterns of inheritance for nuclear genes and maternal inheritance of the organelles
b) sex-linked inheritance
c) paternal patterns inheritance of genes in the mitochondrion
d) all of the above
2) In a monohybrid cross, you can demonstrate
a) independent assortment
b) epistasis
c) segregation and independent assortment
d) segregation
Consider the following phenotypic frequency distributions for plant height and seed weight observed in
an F2 population of 100 plants developed by self pollinating the F1 of a cross between two completely
inbred parents. Questions 3 – 7 refer to these frequency distributions.
3) Plant height is best described as showing what type of inheritance?
a) Quantitative
b) Qualitative
c) Monomorphic
d) Impenetrable
4) Seed weight is best described as showing what type of inheritance?
a) Quantitative
b) Qualitative
c) Monomorphic
d) Impenetrable
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5) If you decided to perform a chi square test on the plant height data, how many degrees of freedom
would you use for your test?
a) 1
b) 2
c) 3
d) 4
6) If your calculated chi square test for plant height showed excellent fit to the expected ratio, how
many loci do you hypothesize are involved in determining plant height?
a) 1
b) 2
c) 3
d) 4
7) If the species in which you are studying plant height is a diploid, how many alleles are possible at
the height locus in any single plant?
a) 1
b) 2
c) 3
d) 4
8) Expected dihybrid ratios for backcross and doubled haploid progeny of crosses between two
completely inbred parents are
a) 1:1
b) 1:1:1
c) 1:1:1:1
d) 1:1:1:1:1:1:1
9) Sex chromosomes are common in animals but they are never observed in plants
a) T
b) F
10) Pleiotropy and penetrance are terms describing the consequences of interactions of alleles at
multiple loci.
a) T
b) F
11) Epistasis is the consequence of alleles at distinct loci failing to assort independently.
a) T
b) F
12) In complementary base pairing,
a) purines always pair with purines
b) purines pair with pyrimidines
c) pairing is accomplished through phosphodiester bonding
d) pyrimidines always pair with pyrimidines
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13) A polynucleotide DNA strand is formed by hydrogen bonding between the phosphate group
attached to the 5' carbon of one nucleotide and the 3' OH group of the next nucleotide.
a) T
b) F
14) A DNA sequence is 5’ATCGCTA3’. Which of the following represents the complementary DNA
sequence?
a) 3’TAGCGAT5’
b) 3’UAGCGAU5’
c) 5’TAGCGAT3’
d) 5’UAGCGAU3’
15) DNA replication is semiconservative because
a) only one parent strand serves as a template for transcription
b) both parental strands serve as templates for replication
c) DNA polymerase is pro-choice
d) promoters have consensus sequences
16) A chromosome contains a single DNA molecule and at different points on the chromosome, either
strand of the helix can serve as a template for transcription.
a) T
b) F
17) Telomeres are of particular interest due to
a) the role of these structures in spindle fiber attachment
b) the relationship of telomere shortening with aging
c) the key role they play in assembly of ribosomes
d) what happens to them after mRNA processing
18) Centromeres and telomeres are organelles that are added to chromosomes during the
sporophytic generation.
a) T
b) F
19) A reasonable range of genome sizes typical for most higher plants is
a) 100 Mb – 15,000 Mb
b) 1 Mb - 10 Mb
c) 100 kb - 1,000 kb
d) 100 – 1,000 nucleotides
20) If a diploid organism is 2n = 20, how many pairs of homologous chromosomes will it have?
a) 0
b) 10
c) 20
d) 40
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21) In higher plants,
a) almost all of the DNA seems to be coding for something.
b) the amount of DNA in the genome corresponds directly to evolutionary complexity.
c) the amount of DNA increases exponentially with each meiosis.
d) a lot of the DNA is composed of transposons, inside of transposons, inside of transposons…
22) Transcription of genes located on the 20 chromosomes of maize occurs
a) in the cytoplasm
b) in the nucleus
c) in both the nucleus and cytoplasm
d) only in translocation heterozygotes
23) The nucleotide sequence of the promoter can be deduced from a mRNA nucleotide sequence.
a) T
b) F
24) What segment of a gene would most likely have consensus regions including CCAAT and TATA
boxes?
a) Promoter
b) Coding region
c) Intron junction
d) Termination signal
25) The synthesis of the mRNA stops when
a) a stop codon is encountered
b) the telomere is reached
c) the polymerase encounters the promoter
d) a specific signal for chain termination is encountered
26) mRNA processing in eukaryotes refers to
a) the addition of a 5’ cap and a 3’ tail and intron removal
b) telomere trimming
c) the first order of compaction
d) degradation of transcripts
27) The DNA code is degenerate because
a) The same codons specify different amino acids in different organisms
b) Start and stop codons are reversed in prokaryotes and eukaryotes
c) The same codon can specify multiple amino acids
d) The same amino acid can be specified by more than one codon
28) Transfer RNAs (tRNAs)
a) are very specialized, with each tRNA able to carry a specified amino acid
b) very generic, with each tRNA able to carry any of a number of amino acids
c) are coded for by sequences in introns
d) are capable of their own transposition
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29) Ribosomes are
a) part of the mitochondrion
b) coded for by nuclear genes
c) formed by exon shuffling
d) double stranded RNA molecules
30) During the elongation phase of the translation process, the next incoming tRNA will
a) arrive at the ribosome’s P site
b) carry an amino acid at its 5’ end
c) have an anti-codon sequence complementary with the codon in the mRNA
31) A single amino acid change in an otherwise identical protein of 300 amino acids could lead to a
very distinct gene product.
a) T
b) F
32) The minimal requirements for a transgene construct are
a) promoter, coding region, and terminator
b) coding region only
c) selectable marker only
d) start and stop codon
33) Selectable markers (e.g. antibiotic resistance genes) are added to transgene constructs
a) to make plants resistant to bacteria
b) to facilitate selection of cells that incorporated and are expressing the transgene
c) to irritate opponents of genetic engineering
d) to prevent the tissue cultures from becoming contaminated
34) If you use a promoter that is expressed only in floral tissue it would be best described as
a) 35S
b) Ribosomal
c) Constitutive
d) Tissue-specific
35) If you wanted to use a reporter gene to determine at what stages and in what tissues a particular
promoter regulates gene expression, you would use
a) GUS or GFP
b) The 35S promoter
c) Golden rice as your test plant
d) The C4P ESPS gene
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36) A genetic engineering technique that involves microprojectile bombardment of tissues with small
particles coated with transgene DNA is known in the popular press as
a) the gene gun method
b) the agrobacterium method
c) the pollen pathway method
d) the sexual reproduction method
37) The principal drawback to the Agrobacterium method of gene transformation is that all the
transformed plants also have crown gall disease.
a) T
b) F
38) If you crossed a transgenic tomato, homozygous for the Bacillus thuringensis (Bt) insect resistance
gene, with a tomato that did not have the Bt gene, the expected phenotypic ratio for insect
resistance: insect susceptibility in the F2 generation would be:
a) 1:1
b) 3:1
c) 9:3:3:1
d) 15:1
39) The creeping bentgrass (Agrostis stolonifera) case study presented in class was of particular interest
because
a) it is a success story where the c4 ESPS gene was completely contained
b) it is an example of using transgenic technology to improve human health via higher vitamin A
content in a species that lacks the biosynthetic pathway
c) it resulted in significant gene migration outside the containment area
d) it is an example of there being no way to determine if transgenes can migrate
40) The alternation of generations refers to:
a) the progeny of controlled crosses between hermaphrodites
b) genetic engineering of parents and offspring
c) the haploid and sporophytic stages of plant life cycles
d) primogeniture and entailment
41) The site of pollen reception on the pistil is the
a) stigma
b) style
c) ovary
d) carpel
42) If you asexually propagate a heterozygote, the progeny will have identical genotypes
a) T
b) F
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43) All components of a monocot seed are derived from the zygote
a) T
b) F
44) In both angiosperm microsporogenesis and megasporogenesis, all products of meioses survive as
gametes:
a) T
b) F
45) In the development of the male gametophyte in higher plants, the
a) generative nucleus undergoes a second mitotic division to give two tube nuclei
b) tube nucleus fertilizes the central cell
c) the generative nucleus undergoes a second mitotic division to give two sperms
d) two sperm produced by a second mitosis in the generative nucleus both fertilize the endosperm
46) In the case of double fertilization, the endosperm is 3n and will have two alleles from the “mother”
and one allele from the father.
a) T
b) F
47) Apomixis is a phenomenon in plants that gives rise to seeds without sex due to
a) parthenogenesis
b) parthenocarpy
c) pleiotropy
d) poltroonism
48) The keen interest in apomixis by seed companies is attributable to the fact that if they understood
the genetic basis they would be able to propagate the same heterozygous genotype, by seed, for
multiple generations.
a) T
b) F
49) An obligate apomict is likely to have tremendous evolutionary success because it can reproduce
sexually or asexually.
a) T
b) F
50) Sporophytic apomixis involves the formation of an unreduced (2n) embryo sac via apospory or
dipospory
a) T
b) F
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51) In the wild blackberry (Rubus spp) example given in class, the AFLPs revealed many
polymorphisms in the native range of the plant and very few (if any) polymorphisms in the places
where the species had been introduced.
a) T
b) F
52) Transposable elements have primary responsibility for the C-value paradox in higher plants. This
means that
a) the elements replace thymine with cytosine, leading to higher percentages of cytosine than
expected
b) the elements cause genome expansion
c) transposable elements cause genome contraction
d) if you centrifuge total DNA extracts, the transposable elements rise to the top as the lightest
fraction
53) Both Class I and Class II elements remain in the DNA and transpose via an mRNA intermediate
that is converted to DNA by RNA polymerase.
a) T
b) F
54) [ Not on exam ]The primary difference between the Ac and Ds elements of maize is that
a) Ac is approximately 100 bp long, whereas Ds is much longer
b) Ac is alternating current whereas Ds is direct scurvy
c) Ac has DNA encoding transposase whereas Ds does not
d) Ds is autonomous whereas Ac is non-autonomous
55) Transposable elements in higher plants have the capacity to routinely excise themselves from the
DNA in a nucleus, pass through the nuclear membrane and cell wall, flow through the xylem and
then enter another cell where they pass through the cell and nuclear membrane and finally insert
themselves into a chromosome in the new host.
a) T
b) F
56) Transposable elements are a genetic curiosity limited to maize and the account for a small
proportion of the total DNA in that species.
a) T
b) F
57) When a transposon shows its effect in a maize kernel, where a gene encodes purple pigment,
a) insertion leads to color and excision leads to lack of color
b) insertion leads to lack of color and excision restores color
c) patters are due to suppression of homologous pairing
d) patterns are due to inversions and translocations
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58) The Evolution Canyon case study of DNA elements causing genome expansion in wild barley was
an example of helitrons creating new genes by creating new combinations of exons.
a) T
b) F
59) The idea of transposon tagging is to
a) watch transposons play tag in the genome
b) put a poly A tail on the transponson
c) clone a gene by looking for loss of function when the transponson goes into that gene
d) use a transposon to degrade double stranded RNA
60) Mutation is a nasty phenomenon with universally deleterious effects.
a) T
b) F
61) Mutation is source of new alleles
a) T
b) F
62) Mutations never occur naturally, they only occur as a consequence of exposure to chemicals or
radiation.
a) T
b) F
63) Mutations cannot be transmitted via asexual reproduction.
a) T
b) F
64) Substitution of one base for another is an example of
a) frameshift
b) transvestitism
c) transversion or transition
65) Which of the following types of mutation accounts for a change in the DNA triplet code but no
change in the amino acid that is specified?
a) Frameshift
b) Silent
c) Nonsense
d) Missense
66) Which of the following types of mutation is defined by a change in a codon that originally specified
an amino acid to a codon that specifies a stop codon?
a) Frameshift
b) Silent
c) Nonsense
d) Missense
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67) An insertion or deletion of nucleotides that are not in multiples of three into an exon will cause a
frameshift
a) T
b) F
68) Mutations in intergenic regions, promoters, exons, and introns will all have the same drastic effects
on phenotypes – causing dominant alleles to become recessive.
a) T
b) F
69) If you assembled a collection of genetically diverse samples of a plant species and measured a
specific phenotype on these plants with accuracy and precision, you will have fulfilled the first two
steps of the seven steps required for genetic dissection of a phenotype.
a) T
b) F
70) Mutations are irreversible
a) T
b) F
71) Induced mutations (i.e. via radiation or chemical treatments) haven been widely and successfully
used in plant improvement because researchers can easily direct which gene will be mutated and
what type of mutation will occur.
a) T
b) F
72) Sterility can be a consequence of major chromosome rearrangements in plants because
a) stigmas lose selectivity.
b) there is no gametophytic generation.
c) in plants heterozygous for the rearrangements, the products of meiosis may be missing critical
genetic information.
d) rearranged plants are deranged
73) A plant heterozygous for a deficiency is expected to be
a) semigamous
b) fully fertile
c) completely sterile
d) semi-sterile
74) A plant homozygous for a duplication is expected to be
a) semigamous
b) fully fertile
c) completely sterile
d) semi-sterile
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75) The type of chromosome aberration that in a plant heterozygous for the event causes a loop to form
at meiosis (and which the instructor could not remember how to draw on the board) is called
a) an inversion
b) a reversion
c) a perversion
d) a transfusion
76) If you compared two linkage maps based on different populations of the same species, where one
map is one based on “normal” parents and the other on parents homozygous for a translocation,
a) the linkage maps would be the same
b) locus orders would be the same, but distance would be different.
c) the linkage maps would show loci in different orders.
d) the map would be missing some loci.
77) Translocations are a type of a chromosome rearrangement due to the breakage and reunion of arms
on the same chromosome.
a) T
b) F
78) Mutations occur in wild plants and weeds but do not have a role in plant domestication and
agriculture
a) T
b) F
79) The semi-dwarf genes that led to the Green Revolution in wheat are loss-of-function mutations
a) T
b) F
80) You use the sequence of a wheat semidwarf gene to design primers that amplify a gene of very
similar sequence from Arabidopsis. This similarity between the wheat and the Arabopsis genes is an
example of
a) transgenic technology
b) syntney
c) homoeology
d) orthology
81) Species Z arose via the spontaneous doubling of it’s own genome and is symbolized as “AAAA”
This is an example of an:
a) allodiploid
b) autodiploid
c) allotetraploid
d) autotetraploid
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82) Autopolyploids will be fully fertile when
a) there is homoeologous pairing.
b) they are triploid.
c) when there is quadrivalent pairing.
d) when there is bivalent pairing.
83) Based on the formula “2n = 4x = 24” you can tell if the organism is an allotetraploid or an
autotetraploid.
a) T
b) F
84) Aneuploids are
a) polyploids with more that four complete sets of homologous chromosomes.
b) doubled haploids with aneurisms.
c) organisms with more or less that exact multiples of the “x” number.
d) superior to diploids in terms of reproductive fitness.
85) Euploidy is the situation where
a) an organism has more or less chromosomes than an exact multiple of the x umber
b) an organism has exact multiples of the basic x number
c) an organism is a 3N from Europe
d) an organism has no centromeres
86) Multiple alleles are possible at a locus but in any diploid individual only two are possible and in
any autotetraploid individual four are possible.
a) T
b) F
87) Species “X” arose via the spontaneous doubling of the genome after an interspecific hybridization
event. It now has the formula 2n = 4x = 32 and is represented as AABB. Species X is an example of
an
a) allodiploid
b) autodiploid
c) autopolyploid
d) allopolyploid
88) How many telomeres are there in a leaf cell of a plant that is 2n = 14?
a) 7
b) 14
c) 28
d) 56
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89) Barley is normally diploid. If you used colchicine to develop an autotetraploid barley, you would
expect to see some sterility due to
a) problems in mitosis
b) induced cytoplasmic male sterility
c) problems in meiosis
d) induced self-incompatibility
90) Allopolyploids arise from
a) itraspecific hybridization
b) intersepcific hybridization
91) Allopolyploids only show full fertility when homoeologous chromosomes pair.
a) T
b) F
92) Spontaneous and induced chromosome doubling both result from altering the function of
a) spindle fibers
b) telomeres
c) centromeres
d) nucleosomes
93) If a plant is triploid and seedless, it must be an allopolyploid
a) T
b) F
94) Triploid watermelons are
a) fully fertile
b) sterile and produced from crosses of autotetraploid x diploid plants
c) sterile because they are propagated asexually
d) sterile because they are self-incompatible
95) Doubled haploids offer advantages for both genetic analysis and plant breeding because
a) each line is completely heterozygous
b) epistasis is eliminated
c) phenotypes are not complicated by dominance/recessive relationships of alleles
d) things produced through tissue culture are better
96) J. Craig Venter is
a) bald
b) The guy who raced the Federally-funded human genome project to the finish line
c) The guy who determined his own DNA sequence
d) Is a coauthor on a recent Science paper reporting the assembly of a Mcyoplasma genome
e) All of the above
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