MCB 317 Exam 2 Actual Final Exam 2026-2027 Newest
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Which of the following can contribute to the continuous phenotypic
nature of polygenic traits?
Dosage effects
Multiple genes contributing to a single trait
Multiple pathways contributing to a single trait
Many hypomorphic alleles in the population
Incomplete dominance
Refer to figure 3.28 in your textbook. Draw a Punnett square and
Distribution curve similar to those in figure 3.28 for a trait that is
governed by 5 alleles of a single gene. Make the same assumptions
that are made in the figure. Based on your analysis answer the following
3 questions.
How many different phenotypes are seen in the population?
What percentage of the population has the most frequently observed
phenotype?
Two phenotypes are least frequently observed. What percentage of
the population has one of the least frequently observed phenotypes?
a) 9
b) 20
c) 4
,You wish to study a particular process using genetics. You carry out a
genetic screen and isolate several mutants that are defective in the
process you are interested in. What procedure/process do you
typically perform to determine how many genes you have identified in
your screen?
Complementation analysis
You have discovered a new type of tropical frog that is indigenous to
the United States. These frogs have three different types of skin
coloration, they can be either red, white or blue depending on which
pigment is produced in their skin cells. Each of the three pigments are
produced as part of a single biochemical pathway with the white
pigment being a precursor compound, the red pigment an intermediate
and the blue pigment the final product. A single gene X codes for the
enzyme that converts the white pigment into the red pigment. Similarly
a single gene Y encodes the enzyme that converts the red pigment to
the blue pigment. In your frog population you have two alleles of each
gene, the X and Y alleles are wild-type alleles that produce functional
enzymes; whereas the x and y alleles are null alleles. You cross two
frogs that are XxYy heterozygotes. What proportion of offspring do
you expect to see?
9 Blue : 3 Red : 4 White
, As discussed in lecture, which of the following processes can be
described by a pathway?
- The catabolic reactions leading to the breakdown of phenylalanine
- Signal transduction
- The biosynthetic reactions leading to the production of adenine
- Krebs cycle
- The events leading to initiation of transcription
- The events leading to initiation of DNA replication
YES: The catabolic reactions leading to the breakdown of
phenylalanine
YES: Signal transduction
YES: The biosynthetic reactions leading to the production of adenine
YES: Krebs cycle
YES: The events leading to initiation of transcription
YES: The events leading to initiation of DNA replication
You are studying a particular signal transduction pathway that can be
schematically diagram exactly as the general pathway shown below. A
single gene codes for the molecule represented by the green triangle.
You have created an organism that is homozygous for a null allele of
that gene. Which one of the following genetic terms MUST describe the
genetic properties associated with the null allele of your gene?
Plieotropy
In lecture we discussed traits that are governed by one gene and traits
that are governed by interactions between two genes. We've also
discussed a number of ratios associated with standard mono-hybrid
and di-hybrid crosses. Which of the ratios below are typically
associated with mono-hybrid crosses?
2:1
1:2:1
3:1
Exam Version With Complete Accurate Real Exam
Questions With Elaborated Answers And Rationales
Verified 100% || Guaranteed Pass A+ ||Brand New!!
Which of the following can contribute to the continuous phenotypic
nature of polygenic traits?
Dosage effects
Multiple genes contributing to a single trait
Multiple pathways contributing to a single trait
Many hypomorphic alleles in the population
Incomplete dominance
Refer to figure 3.28 in your textbook. Draw a Punnett square and
Distribution curve similar to those in figure 3.28 for a trait that is
governed by 5 alleles of a single gene. Make the same assumptions
that are made in the figure. Based on your analysis answer the following
3 questions.
How many different phenotypes are seen in the population?
What percentage of the population has the most frequently observed
phenotype?
Two phenotypes are least frequently observed. What percentage of
the population has one of the least frequently observed phenotypes?
a) 9
b) 20
c) 4
,You wish to study a particular process using genetics. You carry out a
genetic screen and isolate several mutants that are defective in the
process you are interested in. What procedure/process do you
typically perform to determine how many genes you have identified in
your screen?
Complementation analysis
You have discovered a new type of tropical frog that is indigenous to
the United States. These frogs have three different types of skin
coloration, they can be either red, white or blue depending on which
pigment is produced in their skin cells. Each of the three pigments are
produced as part of a single biochemical pathway with the white
pigment being a precursor compound, the red pigment an intermediate
and the blue pigment the final product. A single gene X codes for the
enzyme that converts the white pigment into the red pigment. Similarly
a single gene Y encodes the enzyme that converts the red pigment to
the blue pigment. In your frog population you have two alleles of each
gene, the X and Y alleles are wild-type alleles that produce functional
enzymes; whereas the x and y alleles are null alleles. You cross two
frogs that are XxYy heterozygotes. What proportion of offspring do
you expect to see?
9 Blue : 3 Red : 4 White
, As discussed in lecture, which of the following processes can be
described by a pathway?
- The catabolic reactions leading to the breakdown of phenylalanine
- Signal transduction
- The biosynthetic reactions leading to the production of adenine
- Krebs cycle
- The events leading to initiation of transcription
- The events leading to initiation of DNA replication
YES: The catabolic reactions leading to the breakdown of
phenylalanine
YES: Signal transduction
YES: The biosynthetic reactions leading to the production of adenine
YES: Krebs cycle
YES: The events leading to initiation of transcription
YES: The events leading to initiation of DNA replication
You are studying a particular signal transduction pathway that can be
schematically diagram exactly as the general pathway shown below. A
single gene codes for the molecule represented by the green triangle.
You have created an organism that is homozygous for a null allele of
that gene. Which one of the following genetic terms MUST describe the
genetic properties associated with the null allele of your gene?
Plieotropy
In lecture we discussed traits that are governed by one gene and traits
that are governed by interactions between two genes. We've also
discussed a number of ratios associated with standard mono-hybrid
and di-hybrid crosses. Which of the ratios below are typically
associated with mono-hybrid crosses?
2:1
1:2:1
3:1
