BIL 250 Exam 2 (Chs 4-?) IN PROGRESS UPDATED ACTUAL Questions and
CORRECT Answers
A plant of genotype C/C ; d/d is crossed to c/c ; D/D, B
and the F1 is testcrossed. If the genes in question are
unlinked, the percentage of double homozygous
recessive individuals in the offspring of the testcross will
be:
A) less than 25%.
B) about 25%.
C) more than 25%, but less than 50%.
D) about 50%.
E) more than 50% but less than 75%.
A plant of genotype C/C . d/d is crossed to c/c . D/D, A
and the F1 is testcrossed. If the genes in question are
linked, the percentage of double homozygous recessive
individuals in the offspring of the testcross will be:
A) less than 25%.
B) about 25%.
C) more than 25% but less than 50%.
D) about 50%.
E) more than 50% but less than 75%.
, Pea plant of genotype A/A. B/B crossed to one that is a/a C
. b/b to produce a dihybrid F1. One cell of one F1
individual (genotype A/a . B/b) does meiosis and
produces four gametes of the following genotypes: A . b,
A . b, a .B and a .B. What can be concluded regarding the
relationship between the two genes?
A) A and B are linked; the result is indicative of linkage,
gametes are recombinants.
B) A and B are linked; the result is indicative of linkage
gametes are products of crossovers.
C) A and B could be linked or unlinked; the result is not
indicative of either, because in both cases it's possible to
obtain 100% recombinant gametes from one meiosis.
D) A and B could be linked or unlinked; the result is
unusual as we should never obtain more than 50%
recombinants from one meiosis.
E) A and B are unlinked; the result is indicative of
independent assortment as only two genotypes are
represented among the gametes.
A diploid plant is a trihybrid for flower color (gene "F"), C
leaf size (gene "L") and seed weight (gene "S"); its
phenotype includes red flowers, large leaves, and heavy
seeds. This plant is crossed to a tester plant (which has
white flowers, small leaves, and light seeds). The progeny
is as follows:
heavy, large
heavy, small
light, large
light, small
What can be concluded about the linkage relationships
of the three genes in question?
A) Genes F, L, and S are linked.
B) Genes F and L are linked, while S assorts
independently.
C) Genes F and S are linked, while L assorts
independently.
D) Genes S and L are linked, while F assorts
independently.
E) Genes F, L, and S are unlinked and assort
independently.
In a diploid invertebrate, genes D and E are closely A
linked. Single crossovers between these two genes
occurs only in 1 out of 40 meioses, and multiple
crossovers are never observed. If an individual has the
genotype D e/d E, what percentage of its gametes are
expected to be recombinant (either DE or de)?
A) 1.25%
B) 2.5%
C) 4%
D) 5%
E) 20%
CORRECT Answers
A plant of genotype C/C ; d/d is crossed to c/c ; D/D, B
and the F1 is testcrossed. If the genes in question are
unlinked, the percentage of double homozygous
recessive individuals in the offspring of the testcross will
be:
A) less than 25%.
B) about 25%.
C) more than 25%, but less than 50%.
D) about 50%.
E) more than 50% but less than 75%.
A plant of genotype C/C . d/d is crossed to c/c . D/D, A
and the F1 is testcrossed. If the genes in question are
linked, the percentage of double homozygous recessive
individuals in the offspring of the testcross will be:
A) less than 25%.
B) about 25%.
C) more than 25% but less than 50%.
D) about 50%.
E) more than 50% but less than 75%.
, Pea plant of genotype A/A. B/B crossed to one that is a/a C
. b/b to produce a dihybrid F1. One cell of one F1
individual (genotype A/a . B/b) does meiosis and
produces four gametes of the following genotypes: A . b,
A . b, a .B and a .B. What can be concluded regarding the
relationship between the two genes?
A) A and B are linked; the result is indicative of linkage,
gametes are recombinants.
B) A and B are linked; the result is indicative of linkage
gametes are products of crossovers.
C) A and B could be linked or unlinked; the result is not
indicative of either, because in both cases it's possible to
obtain 100% recombinant gametes from one meiosis.
D) A and B could be linked or unlinked; the result is
unusual as we should never obtain more than 50%
recombinants from one meiosis.
E) A and B are unlinked; the result is indicative of
independent assortment as only two genotypes are
represented among the gametes.
A diploid plant is a trihybrid for flower color (gene "F"), C
leaf size (gene "L") and seed weight (gene "S"); its
phenotype includes red flowers, large leaves, and heavy
seeds. This plant is crossed to a tester plant (which has
white flowers, small leaves, and light seeds). The progeny
is as follows:
heavy, large
heavy, small
light, large
light, small
What can be concluded about the linkage relationships
of the three genes in question?
A) Genes F, L, and S are linked.
B) Genes F and L are linked, while S assorts
independently.
C) Genes F and S are linked, while L assorts
independently.
D) Genes S and L are linked, while F assorts
independently.
E) Genes F, L, and S are unlinked and assort
independently.
In a diploid invertebrate, genes D and E are closely A
linked. Single crossovers between these two genes
occurs only in 1 out of 40 meioses, and multiple
crossovers are never observed. If an individual has the
genotype D e/d E, what percentage of its gametes are
expected to be recombinant (either DE or de)?
A) 1.25%
B) 2.5%
C) 4%
D) 5%
E) 20%
