K322 Exam 1: Genetics & Molecular Biology Questions
With Complete Solutions
1. Controlled Crosses Between Plants Correct Answers Pea
plants are capable of self-fertilization and artificial cross-
fertilization
Self-fertilization occurs naturally
Cross-fertilization involves removing the anthers from a flower
and introducing pollen of the desired type with a small brush
2. Pure-Breeding Strains Correct Answers Mendel took 2 years
prior to beginning his experiments to establish pure-breeding (or
true-breeding) strains
These are strains that consistently produce the same phenotype
when self fertilized
Each experiment began with crosses between two pure-breeding
parental generation plants (P generation) that produced offspring
called F1 (first filial generation)
These plants are homozyogous
p = parents
filial = generations after the parent
3. Further Experimental Crosses Correct Answers Pure-
breeding parental plants, when crossed, produce F1 that all have
the same phenotype
,F1 offspring that are crossed to one another produce the next
generation of offspring, the second filial generation (F2)
These can be crossed to produce the third filial generation (F3)
and so on, as needed
---------------------------------------------------
Are you your grandparents F2 generation? Might need to google
this one. No, my parents weren't siblings
Take f1 and cross with themselves to produce F2....
3:1 purple to white
4. Dichotomous (binary) Phenotypes Correct Answers Each of
the traits Mendel chose had just two possible phenotypes, or
dichotomous forms
These were easily distinguished from one another with no
intermediate phenotypes
Early in his experiments, he worked with an additional trait, but
discontinued it when he noticed a connection with another trait
5. Quantification of Results Correct Answers Mendel counted
the number of progeny plants of each type and counted many
offspring from each cross
He identified patterns in his results, such as the consistent ratios
between phenotypes
The ratios he detected are the foundation of his laws of heredity
,A family has 5 children. What is the probability of having 3
boys and 2 girls? Correct Answers 5/6
A geneticist discovers an obese mouse in his laboratory colony.
He breeds this obese mouse with a normal mouse. All the F1
mice from this cross are normal in size. When he interbreeds
two F1 mice, eight of the F2 mice are normal in size and two are
obese. The geneticist then intercrosses two of his obese mice,
and he finds that all of the progeny from this cross are obese.
These results lead the geneticist to conclude that obesity in mice
results from a recessive allele.
A second geneticist at a different university also discovers an
obese mouse in her laboratory colony. She carries out the same
crosses as the first geneticist and obtains the same results. She
also concludes that obesity in mice results from a recessive
allele. One day, the two geneticist meet at a genetics conference,
learn of each others experiments, and decided to exchange mice.
They both find that, when they cross two obese mice from the
differ Correct Answers The two obesity alleles are recessive to
the wild type alleles but are located at different loci.
A man Joe, has classic hemophilia, an X-linked recessive
disease. Classify each person depending on whether or not Joe
could have inherited the hemophilia gene from him or her.
Correct Answers Could have inherited
- maternal grandmother
- maternal grandfather
Could not have inherited
- paternal grandmother
, - paternal grandfather
A pedigree with a family with a rare genetic disorder is shown.
Use the pedigree to determine the mode of inheritance of the
disorder.
GI: father
GII: 1/2 son affected and 2/3 girls affected
GII: husband and wife both have trait and pass to one of their
sons Correct Answers Autosomal dominant
A trait, such as height, has high heritability because much of the
variation between individuals is the result of genetic variation.
However, not all of the variation for height in a population can
be attributed to genetic variation alone.
Why does genetic variation not always determine the differences
in a given trait between individuals? Correct Answers
Environmental influences can change gene expression
A women has blood type A MM. Her child has blood type AB
MN. The blood types of the potential fathers are given in the
table:
George- O NN
Tom- AB MN
Bill- B MN
Claude- A NN
Henry- AB MM
Based on their blood types, which of these men could be the
father of this child? Correct Answers Could be the father
With Complete Solutions
1. Controlled Crosses Between Plants Correct Answers Pea
plants are capable of self-fertilization and artificial cross-
fertilization
Self-fertilization occurs naturally
Cross-fertilization involves removing the anthers from a flower
and introducing pollen of the desired type with a small brush
2. Pure-Breeding Strains Correct Answers Mendel took 2 years
prior to beginning his experiments to establish pure-breeding (or
true-breeding) strains
These are strains that consistently produce the same phenotype
when self fertilized
Each experiment began with crosses between two pure-breeding
parental generation plants (P generation) that produced offspring
called F1 (first filial generation)
These plants are homozyogous
p = parents
filial = generations after the parent
3. Further Experimental Crosses Correct Answers Pure-
breeding parental plants, when crossed, produce F1 that all have
the same phenotype
,F1 offspring that are crossed to one another produce the next
generation of offspring, the second filial generation (F2)
These can be crossed to produce the third filial generation (F3)
and so on, as needed
---------------------------------------------------
Are you your grandparents F2 generation? Might need to google
this one. No, my parents weren't siblings
Take f1 and cross with themselves to produce F2....
3:1 purple to white
4. Dichotomous (binary) Phenotypes Correct Answers Each of
the traits Mendel chose had just two possible phenotypes, or
dichotomous forms
These were easily distinguished from one another with no
intermediate phenotypes
Early in his experiments, he worked with an additional trait, but
discontinued it when he noticed a connection with another trait
5. Quantification of Results Correct Answers Mendel counted
the number of progeny plants of each type and counted many
offspring from each cross
He identified patterns in his results, such as the consistent ratios
between phenotypes
The ratios he detected are the foundation of his laws of heredity
,A family has 5 children. What is the probability of having 3
boys and 2 girls? Correct Answers 5/6
A geneticist discovers an obese mouse in his laboratory colony.
He breeds this obese mouse with a normal mouse. All the F1
mice from this cross are normal in size. When he interbreeds
two F1 mice, eight of the F2 mice are normal in size and two are
obese. The geneticist then intercrosses two of his obese mice,
and he finds that all of the progeny from this cross are obese.
These results lead the geneticist to conclude that obesity in mice
results from a recessive allele.
A second geneticist at a different university also discovers an
obese mouse in her laboratory colony. She carries out the same
crosses as the first geneticist and obtains the same results. She
also concludes that obesity in mice results from a recessive
allele. One day, the two geneticist meet at a genetics conference,
learn of each others experiments, and decided to exchange mice.
They both find that, when they cross two obese mice from the
differ Correct Answers The two obesity alleles are recessive to
the wild type alleles but are located at different loci.
A man Joe, has classic hemophilia, an X-linked recessive
disease. Classify each person depending on whether or not Joe
could have inherited the hemophilia gene from him or her.
Correct Answers Could have inherited
- maternal grandmother
- maternal grandfather
Could not have inherited
- paternal grandmother
, - paternal grandfather
A pedigree with a family with a rare genetic disorder is shown.
Use the pedigree to determine the mode of inheritance of the
disorder.
GI: father
GII: 1/2 son affected and 2/3 girls affected
GII: husband and wife both have trait and pass to one of their
sons Correct Answers Autosomal dominant
A trait, such as height, has high heritability because much of the
variation between individuals is the result of genetic variation.
However, not all of the variation for height in a population can
be attributed to genetic variation alone.
Why does genetic variation not always determine the differences
in a given trait between individuals? Correct Answers
Environmental influences can change gene expression
A women has blood type A MM. Her child has blood type AB
MN. The blood types of the potential fathers are given in the
table:
George- O NN
Tom- AB MN
Bill- B MN
Claude- A NN
Henry- AB MM
Based on their blood types, which of these men could be the
father of this child? Correct Answers Could be the father
