1. Who is considered the father of modern genetics?
A) Charles Darwin
B) Gregor Mendel
C) Watson and Crick
D) Louis Pasteur
Answer: B) Gregor Mendel
2. Mendel’s law of segregation states that:
A) Alleles segregate independently during gamete formation
B) The two alleles for each trait separate during gamete formation
C) Alleles of different traits assort independently
D) None of the above
Answer: B) The two alleles for each trait separate during gamete formation
3. The law of independent assortment applies to genes located on:
A) The same chromosome
B) Different chromosomes
C) The same allele
D) Homologous chromosomes
Answer: B) Different chromosomes
4. What was the experimental organism used by Gregor Mendel in his studies?
A) Fruit flies
B) Pea plants
C) Mice
D) Corn
Answer: B) Pea plants
5. In Mendel’s experiments, the tall plant trait (T) was dominant over the short plant trait (t). If a homozygous tall plant (TT) is crossed with a short plant (tt), what is the genotype of the F1 generation?
A) TT
B) Tt
C) tt
D) TtTt
Answer: B) Tt
6. What is the phenotypic ratio of the F2 generation in a dihybrid cross?
A) 3:1
B) 9:3:3:1
C) 1:1:1:1
D) 1:2:1
Answer: B) 9:3:3:1
7. In Mendel’s experiments, a monohybrid cross between two heterozygous pea plants (Tt x Tt) resulted in which phenotypic ratio?
A) 1:1
B) 3:1
C) 9:3:3:1
D) 1:2:1
Answer: B) 3:1
8. In the law of independent assortment, genes for different traits:
A) Must be located on the same chromosome
B) Assort independently into gametes
C) Segregate together
D) Do not undergo recombination
Answer: B) Assort independently into gametes
9. The term “genotype” refers to:
A) The physical appearance of an organism
B) The genetic makeup of an organism
C) The number of chromosomes
D) The phenotype of an organism
Answer: B) The genetic makeup of an organism
10. What is the expected phenotypic ratio of a cross between a homozygous dominant (TT) and a homozygous recessive (tt) pea plant?
A) 1:1
B) 3:1
C) 1:0
D) 4:0
Answer: C) 1:0
11. Which of the following is true about Mendel’s experiments?
A) He crossed plants of different sizes
B) He cross-pollinated plants to study inheritance
C) He used animals for his studies
D) He studied only one trait at a time
Answer: B) He cross-pollinated plants to study inheritance
12. What is the term for organisms that have two identical alleles for a trait?
A) Homozygous
B) Heterozygous
C) Recessive
D) Dominant
Answer: A) Homozygous
13. The allele for purple flowers (P) is dominant over the allele for white flowers (p). What is the expected ratio in a cross between two heterozygous plants (Pp x Pp)?
A) 1:1
B) 3:1
C) 9:3:3:1
D) 1:2:1
Answer: B) 3:1
14. In a test cross, a plant with an unknown genotype is crossed with a:
A) Homozygous recessive plant
B) Homozygous dominant plant
C) Heterozygous plant
D) None of the above
Answer: A) Homozygous recessive plant
15. If a pea plant with a genotype of TtPp is crossed with another plant with a genotype of TtPp, what fraction of the offspring will be homozygous recessive for both traits?
A) 1/16
B) 1/4
C) 1/8
D) 9/16
Answer: A) 1/16
16. The physical expression of a gene is referred to as its:
A) Genotype
B) Phenotype
C) Allele
D) Gamete
Answer: B) Phenotype
17. Which of the following statements is true according to Mendel’s law of segregation?
A) Each allele has an equal chance of being passed to the offspring
B) Each allele is inherited separately from the other
C) The dominant allele hides the effect of the recessive allele
D) Both A and B are correct
Answer: D) Both A and B are correct
18. The genotype of a homozygous recessive individual would be:
A) AA
B) Aa
C) aa
D) AB
Answer: C) aa
19. The term “heterozygous” refers to an organism that:
A) Has two identical alleles for a gene
B) Has two different alleles for a gene
C) Has no dominant allele
D) Is purebred for a trait
Answer: B) Has two different alleles for a gene
20. In a monohybrid cross, what is the probability of getting a heterozygous offspring if both parents are heterozygous?
A) 1/2
B) 1/4
C) 3/4
D) 1/3
Answer: A) 1/2
21. What did Mendel use to perform his inheritance experiments?
A) Fruit flies
B) Mice
C) Pea plants
D) Birds
Answer: C) Pea plants
22. Which law of inheritance explains the separation of alleles during gamete formation?
A) Law of independent assortment
B) Law of dominance
C) Law of segregation
D) Law of incomplete dominance
Answer: C) Law of segregation
23. In a dihybrid cross between two heterozygous plants (AaBb x AaBb), what is the expected genotypic ratio of the F2 generation?
A) 1:1
B) 3:1
C) 9:3:3:1
D) 9:7
Answer: C) 9:3:3:1
24. When two alleles for a gene are identical, the individual is said to be:
A) Heterozygous
B) Homozygous
C) Dominant
D) Recessive
Answer: B) Homozygous
25. In Mendelian inheritance, a recessive allele is expressed only when:
A) The individual is homozygous recessive
B) It is present with a dominant allele
C) Both alleles are dominant
D) It is found on the X chromosome
Answer: A) The individual is homozygous recessive
26. A test cross is used to determine:
A) The dominant allele of an individual
B) The genotype of a parent with a dominant phenotype
C) The phenotype of a heterozygous individual
D) The inheritance pattern of recessive alleles
Answer: B) The genotype of a parent with a dominant phenotype
27. What does the law of independent assortment state?
A) Alleles for different traits are inherited together
B) Alleles for different traits separate independently during gamete formation
C) Alleles for the same trait separate independently
D) Genes are inherited together on the same chromosome
Answer: B) Alleles for different traits separate independently during gamete formation
28. What is the result of a cross between a heterozygous tall plant (Tt) and a short plant (tt)?
A) All tall plants
B) Half tall and half short plants
C) All short plants
D) 3/4 tall and 1/4 short plants
Answer: B) Half tall and half short plants
29. In a monohybrid cross, if the parent genotypes are Tt x Tt, what fraction of the offspring will be homozygous dominant?
A) 1/4
B) 1/2
C) 3/4
D) 1/16
Answer: A) 1/4
30. The genetic makeup of an organism is its:
A) Phenotype
B) Genotype
C) Gametes
D) Alleles
Answer: B) Genotype
These MCQs cover various aspects of Mendel’s laws of inheritance, including key concepts, definitions, and examples that are useful for students to understand the fundamentals of genetics.
