BIOD 210 Module 2 Exam – Genetics Portage Learning – (2026)
Actual Questions & Answers — 70 Questions and Answers
Already Graded A+ Premium Exam Tested And Verified
Subject Area Genetics
Description This exam covers advanced topics in genetics including Mendelian and
non-Mendelian inheritance, molecular genetics, population genetics, epigenetics,
and genetic technologies. It emphasizes critical thinking, data analysis, and
application of genetic principles to complex scenarios.
Expected Grade A+
Total Questions 70
Duration 3 hours
Learning Outcomes 1. Analyze inheritance patterns using pedigree and probability calculations
2. Evaluate the molecular mechanisms of gene expression and regulation
3. Apply population genetics models to real-world data
4. Interpret epigenetic modifications and their impact on phenotype
5. Critically assess genetic technologies and their ethical implications
Accreditation This exam meets the rigorous standards of Ivy League and R1 research
universities, requiring deep conceptual understanding and multi-step reasoning.
Page 1
,1. In a study of a rare autosomal dominant disorder with complete penetrance, a
large pedigree shows that affected individuals always have at least one affected
parent, except for one individual who has two unaffected parents. Which of the
following is the most likely explanation for this observation?
A. Incomplete penetrance
B. Germline mosaicism in one parent
C. De novo mutation
D. Anticipation
Answer: C. De novo mutation
A de novo mutation occurs when a new mutation arises in a germ cell of an unaffected
parent, leading to an affected offspring without a family history. Incomplete penetrance
would allow an unaffected carrier parent, but here both parents are unaffected.
Germline mosaicism could also produce an affected child from unaffected parents, but
it is less common than de novo mutation. Anticipation involves increasing severity in
successive generations, not absence of affected parents.
2. A researcher is analyzing a quantitative trait in a plant species and finds that the
trait distribution in the F2 generation is continuous and unimodal. The F1
generation shows an intermediate phenotype. Which of the following best explains
the genetic basis of this trait?
A. Single gene with incomplete dominance
B. Multiple genes with additive effects
C. Single gene with codominance
D. Epistasis between two genes
Answer: B. Multiple genes with additive effects
Continuous variation in the F2 generation suggests polygenic inheritance with multiple
genes contributing additively. A single gene with incomplete dominance would produce
three distinct phenotypes (not continuous). Codominance also yields discrete categories.
Epistasis typically produces modified Mendelian ratios, not continuous distributions.
Page 2
,3. In a population of 10,000 individuals, the frequency of a recessive disease allele is
0.01. Assuming Hardy-Weinberg equilibrium, what is the expected number of
carriers (heterozygotes) in the population?
A. 198
B. 200
C. 99
D. 1,000
Answer: A. 198
Under HWE, carrier frequency = 2pq, where p = 0.99, q = 0.01. So 2 * 0.99 * 0.01 =
0.0198. Multiply by 10,000 gives 198 carriers. Option B (200) is approximate but not
exact. Option C is half that (only affected individuals). Option D is 10% of population,
too high.
4. A scientist treats cells with a drug that inhibits DNA methyltransferase. Which of
the following is the most likely immediate effect on gene expression?
A. Global decrease in transcription
B. Global increase in transcription
C. Activation of silenced tumor suppressor genes
D. Increased histone acetylation
Answer: C. Activation of silenced tumor suppressor genes
DNA methyltransferase inhibition reduces DNA methylation, which typically represses
gene expression. Hypomethylation can reactivate silenced genes, such as tumor
suppressor genes. This does not cause a global increase in transcription (option B)
because many genes are not silenced by methylation. Option A is opposite. Histone
acetylation is a separate modification.
Page 3
, 5. A researcher uses CRISPR-Cas9 to introduce a specific point mutation in a gene
in human cell lines. However, sequencing reveals that many cells have small
insertions or deletions (indels) at the target site instead of the intended mutation.
Which of the following best explains this outcome?
A. Homology-directed repair (HDR) was used without a repair template
B. Non-homologous end joining (NHEJ) repaired the double-strand break
C. The guide RNA had off-target effects
D. The Cas9 nuclease was inactive
Answer: B. Non-homologous end joining (NHEJ) repaired the double-strand break
CRISPR-Cas9 creates double-strand breaks. NHEJ is an error-prone repair pathway
that frequently introduces indels. HDR requires a repair template to introduce precise
mutations; without it, NHEJ dominates. Off-target effects would cause edits at other
loci, not indels at the target. Inactive Cas9 would produce no edits.
6. A patient presents with a family history of early-onset breast and ovarian cancer.
Genetic testing reveals a mutation in the BRCA1 gene. Which of the following best
describes the inheritance pattern and risk implications?
A. Autosomal recessive; both parents must be carriers
B. Autosomal dominant; each child has a 50% chance of inheriting the mutation
C. X-linked dominant; only females are affected
D. Mitochondrial inheritance; only maternal transmission
Answer: B. Autosomal dominant; each child has a 50% chance of inheriting the
mutation
BRCA1 mutations are inherited in an autosomal dominant manner with incomplete
penetrance. Each offspring has a 50% chance of inheriting the mutation. Autosomal
recessive would require two mutations, not typical for early-onset cases. X-linked and
mitochondrial patterns do not match BRCA1 inheritance.
Page 4
Actual Questions & Answers — 70 Questions and Answers
Already Graded A+ Premium Exam Tested And Verified
Subject Area Genetics
Description This exam covers advanced topics in genetics including Mendelian and
non-Mendelian inheritance, molecular genetics, population genetics, epigenetics,
and genetic technologies. It emphasizes critical thinking, data analysis, and
application of genetic principles to complex scenarios.
Expected Grade A+
Total Questions 70
Duration 3 hours
Learning Outcomes 1. Analyze inheritance patterns using pedigree and probability calculations
2. Evaluate the molecular mechanisms of gene expression and regulation
3. Apply population genetics models to real-world data
4. Interpret epigenetic modifications and their impact on phenotype
5. Critically assess genetic technologies and their ethical implications
Accreditation This exam meets the rigorous standards of Ivy League and R1 research
universities, requiring deep conceptual understanding and multi-step reasoning.
Page 1
,1. In a study of a rare autosomal dominant disorder with complete penetrance, a
large pedigree shows that affected individuals always have at least one affected
parent, except for one individual who has two unaffected parents. Which of the
following is the most likely explanation for this observation?
A. Incomplete penetrance
B. Germline mosaicism in one parent
C. De novo mutation
D. Anticipation
Answer: C. De novo mutation
A de novo mutation occurs when a new mutation arises in a germ cell of an unaffected
parent, leading to an affected offspring without a family history. Incomplete penetrance
would allow an unaffected carrier parent, but here both parents are unaffected.
Germline mosaicism could also produce an affected child from unaffected parents, but
it is less common than de novo mutation. Anticipation involves increasing severity in
successive generations, not absence of affected parents.
2. A researcher is analyzing a quantitative trait in a plant species and finds that the
trait distribution in the F2 generation is continuous and unimodal. The F1
generation shows an intermediate phenotype. Which of the following best explains
the genetic basis of this trait?
A. Single gene with incomplete dominance
B. Multiple genes with additive effects
C. Single gene with codominance
D. Epistasis between two genes
Answer: B. Multiple genes with additive effects
Continuous variation in the F2 generation suggests polygenic inheritance with multiple
genes contributing additively. A single gene with incomplete dominance would produce
three distinct phenotypes (not continuous). Codominance also yields discrete categories.
Epistasis typically produces modified Mendelian ratios, not continuous distributions.
Page 2
,3. In a population of 10,000 individuals, the frequency of a recessive disease allele is
0.01. Assuming Hardy-Weinberg equilibrium, what is the expected number of
carriers (heterozygotes) in the population?
A. 198
B. 200
C. 99
D. 1,000
Answer: A. 198
Under HWE, carrier frequency = 2pq, where p = 0.99, q = 0.01. So 2 * 0.99 * 0.01 =
0.0198. Multiply by 10,000 gives 198 carriers. Option B (200) is approximate but not
exact. Option C is half that (only affected individuals). Option D is 10% of population,
too high.
4. A scientist treats cells with a drug that inhibits DNA methyltransferase. Which of
the following is the most likely immediate effect on gene expression?
A. Global decrease in transcription
B. Global increase in transcription
C. Activation of silenced tumor suppressor genes
D. Increased histone acetylation
Answer: C. Activation of silenced tumor suppressor genes
DNA methyltransferase inhibition reduces DNA methylation, which typically represses
gene expression. Hypomethylation can reactivate silenced genes, such as tumor
suppressor genes. This does not cause a global increase in transcription (option B)
because many genes are not silenced by methylation. Option A is opposite. Histone
acetylation is a separate modification.
Page 3
, 5. A researcher uses CRISPR-Cas9 to introduce a specific point mutation in a gene
in human cell lines. However, sequencing reveals that many cells have small
insertions or deletions (indels) at the target site instead of the intended mutation.
Which of the following best explains this outcome?
A. Homology-directed repair (HDR) was used without a repair template
B. Non-homologous end joining (NHEJ) repaired the double-strand break
C. The guide RNA had off-target effects
D. The Cas9 nuclease was inactive
Answer: B. Non-homologous end joining (NHEJ) repaired the double-strand break
CRISPR-Cas9 creates double-strand breaks. NHEJ is an error-prone repair pathway
that frequently introduces indels. HDR requires a repair template to introduce precise
mutations; without it, NHEJ dominates. Off-target effects would cause edits at other
loci, not indels at the target. Inactive Cas9 would produce no edits.
6. A patient presents with a family history of early-onset breast and ovarian cancer.
Genetic testing reveals a mutation in the BRCA1 gene. Which of the following best
describes the inheritance pattern and risk implications?
A. Autosomal recessive; both parents must be carriers
B. Autosomal dominant; each child has a 50% chance of inheriting the mutation
C. X-linked dominant; only females are affected
D. Mitochondrial inheritance; only maternal transmission
Answer: B. Autosomal dominant; each child has a 50% chance of inheriting the
mutation
BRCA1 mutations are inherited in an autosomal dominant manner with incomplete
penetrance. Each offspring has a 50% chance of inheriting the mutation. Autosomal
recessive would require two mutations, not typical for early-onset cases. X-linked and
mitochondrial patterns do not match BRCA1 inheritance.
Page 4
