BIO 212 Practice Quiz 2 Questions And Answers
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In a series of mapping experiments, the recombination frequencies for four different linked genes of
Drosophila were determined as shown in the figure. Based on this information, what is the order of these
genes on a chromosome map? ANS b-rb-cn-vg
What is it called when a gene produces multiple phenotypes? ANS Pleiotropy
A certain kind of snail can have a right-handed direction of shell coiling (DD or Dd) or left-handed
coiling (dd). However, if direction of coiling is due to a protein deposited by the mother in the egg
cytoplasm, then a Dd egg-producing snail and a dd sperm-producing snail will have offspring of which
genotype(s) and phenotype(s)? ANS 1/2 Dd:1/2 dd; all right-coiling
In the epistasis discussion, what color would a lab dog with BbEe be? ANS black
Which of the following statements correctly describes the reason that closely linked genes are typically
inherited together? ANS They are located close together on the same chromosome.
When Thomas Hunt Morgan crossed his red-eyed F1generation flies to each other, the F2 generation
included both red- and white-eyed flies. Remarkably, all the white-eyed flies were male. What was the
explanation for this result? ANS The gene involved is located on the X chromosome.
Map units on a linkage map cannot be relied upon to calculate physical distances on a chromosome for
which of the following reasons? ANS The frequency of crossing over varies along the length of the
chromosome.
In incomplete dominance, when a homozygous dominant red flower is mated with a homozygous
recessive white flower, what does the offspring look like? ANS 100% pink
If a homozygous dominant purple flowered plant is crossed with a homozygous recessive white flowered
plant, and the offspring are crossed with each other, which of the following is possible? ANS 75%
purple
, What is a syndrome? ANS a group of traits typically found in conjunction with a particular
chromosomal aberration or gene mutation
Which of the following statements regarding gene linkage is correct? ANS The closer two genes are
on a chromosome, the lower the probability that a crossover will occur between them.
What characteristic shows codominance? ANS blood type
Any abnormal number of chromosomes in the zygote is called: ANS aneuploid
What happens to deep pink colored flowers if hydrangeas are grown in pH 4.5 soil? ANS become
deep blue
All female mammals have one active X chromosome per cell instead of two. What causes this to happen?
ANS activation of the XIST gene on the X chromosome that will become the Barr body
What is it called when there is an additive effect of two or more genes on a single phenotype? ANS
polygenic
Which of the following correctly describes a Philadelphia chromosome? ANS a human chromosome
22 that has had a specific translocation
In birds, sex is determined by a ZW chromosome scheme. Males are ZZ and females are ZW. A recessive
lethal allele that causes death of the embryo is sometimes present on the Z chromosome in pigeons. What
would be the sex ratio in the offspring of a cross between a male that is heterozygous for the lethal allele
and a normal female? ANS 2:1 male to female
In a Drosophila experiment, a cross was made between homozygous wild-type females and yellow-bodied
males. All of the resulting F1s were phenotypically wild type. However, adult flies of the F2 generation
(resulting from matings of the F1s) had the characteristics shown in the figure. How is the mutant allele
for yellow body inherited? ANS It is X-linked
Latest Updates
In a series of mapping experiments, the recombination frequencies for four different linked genes of
Drosophila were determined as shown in the figure. Based on this information, what is the order of these
genes on a chromosome map? ANS b-rb-cn-vg
What is it called when a gene produces multiple phenotypes? ANS Pleiotropy
A certain kind of snail can have a right-handed direction of shell coiling (DD or Dd) or left-handed
coiling (dd). However, if direction of coiling is due to a protein deposited by the mother in the egg
cytoplasm, then a Dd egg-producing snail and a dd sperm-producing snail will have offspring of which
genotype(s) and phenotype(s)? ANS 1/2 Dd:1/2 dd; all right-coiling
In the epistasis discussion, what color would a lab dog with BbEe be? ANS black
Which of the following statements correctly describes the reason that closely linked genes are typically
inherited together? ANS They are located close together on the same chromosome.
When Thomas Hunt Morgan crossed his red-eyed F1generation flies to each other, the F2 generation
included both red- and white-eyed flies. Remarkably, all the white-eyed flies were male. What was the
explanation for this result? ANS The gene involved is located on the X chromosome.
Map units on a linkage map cannot be relied upon to calculate physical distances on a chromosome for
which of the following reasons? ANS The frequency of crossing over varies along the length of the
chromosome.
In incomplete dominance, when a homozygous dominant red flower is mated with a homozygous
recessive white flower, what does the offspring look like? ANS 100% pink
If a homozygous dominant purple flowered plant is crossed with a homozygous recessive white flowered
plant, and the offspring are crossed with each other, which of the following is possible? ANS 75%
purple
, What is a syndrome? ANS a group of traits typically found in conjunction with a particular
chromosomal aberration or gene mutation
Which of the following statements regarding gene linkage is correct? ANS The closer two genes are
on a chromosome, the lower the probability that a crossover will occur between them.
What characteristic shows codominance? ANS blood type
Any abnormal number of chromosomes in the zygote is called: ANS aneuploid
What happens to deep pink colored flowers if hydrangeas are grown in pH 4.5 soil? ANS become
deep blue
All female mammals have one active X chromosome per cell instead of two. What causes this to happen?
ANS activation of the XIST gene on the X chromosome that will become the Barr body
What is it called when there is an additive effect of two or more genes on a single phenotype? ANS
polygenic
Which of the following correctly describes a Philadelphia chromosome? ANS a human chromosome
22 that has had a specific translocation
In birds, sex is determined by a ZW chromosome scheme. Males are ZZ and females are ZW. A recessive
lethal allele that causes death of the embryo is sometimes present on the Z chromosome in pigeons. What
would be the sex ratio in the offspring of a cross between a male that is heterozygous for the lethal allele
and a normal female? ANS 2:1 male to female
In a Drosophila experiment, a cross was made between homozygous wild-type females and yellow-bodied
males. All of the resulting F1s were phenotypically wild type. However, adult flies of the F2 generation
(resulting from matings of the F1s) had the characteristics shown in the figure. How is the mutant allele
for yellow body inherited? ANS It is X-linked
