BIOD210 (Mendelian Genetics) Comprehensive Test Review 2025 (Qns & Ans)

BIOD210

Mendelian Genetics

Comprehensive Test Review (Qns & Ans)

2025



1. Which of the following best describes the concept of Mendel's
law of independent assortment?
- A) Alleles of different genes segregate together during gamete
formation
- B) Alleles of different genes segregate independently of each
other during gamete formation
- C) Alleles of the same gene segregate together during gamete
formation
- D) Alleles of the same gene segregate independently of each
other during gamete formation
- ANS: B) Alleles of different genes segregate independently
of each other during gamete formation
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, - Rationale: Mendel's law of independent assortment states
that alleles of different genes segregate independently during
gamete formation, leading to genetic variation.


2. What is the primary purpose of a test cross in genetics?
- A) To determine the genotype of a dominant phenotype
- B) To measure gene expression levels
- C) To identify genetic mutations
- D) To sequence DNA
- ANS: A) To determine the genotype of a dominant
phenotype
- Rationale: A test cross is used to determine the genotype of
an organism with a dominant phenotype by crossing it with a
homozygous recessive individual.


3. Which of the following ratios is expected in the F2 generation
of a dihybrid cross involving two heterozygous individuals?
- A) 9:3:3:1
- B) 3:1
- C) 1:2:1
- D) 1:1
- ANS: A) 9:3:3:1

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, - Rationale: In the F2 generation of a dihybrid cross
involving two heterozygous individuals, the expected phenotypic
ratio is 9:3:3:1, representing the four possible combinations of the
two traits.


Fill-in-the-Blank Questions
4. In Mendelian genetics, __________ refers to the physical
expression of a gene.
- ANS: Phenotype
- Rationale: The phenotype refers to the physical expression
of a gene, such as observable traits like flower color or seed
shape.


5. Mendel's law of __________ states that alleles segregate
randomly into gametes, ensuring each gamete receives only one
allele from each gene pair.
- ANS: Segregation
- Rationale: Mendel's law of segregation states that alleles
segregate randomly into gametes, ensuring each gamete receives
only one allele from each gene pair.


6. A __________ individual has two different alleles for a
specific gene.
- ANS: Heterozygous

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, - Rationale: A heterozygous individual has two different
alleles for a specific gene, resulting in a combination of dominant
and recessive traits.


True/False Questions
7. True or False: Mendelian genetics can be applied to all traits
in all organisms.
- ANS: False
- Rationale: Mendelian genetics applies primarily to traits
governed by single genes with clear dominant and recessive
alleles. Complex traits involving multiple genes or environmental
factors may not follow Mendelian inheritance patterns.


8. True or False: In a monohybrid cross between two
heterozygous individuals, the expected genotypic ratio in the F2
generation is 1:2:1.
- ANS: True
- Rationale: In a monohybrid cross between two
heterozygous individuals, the expected genotypic ratio in the F2
generation is 1:2:1, representing the proportions of homozygous
dominant, heterozygous, and homozygous recessive individuals.


9. True or False: Linked genes do not follow Mendel's law of
independent assortment.
- ANS: True
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