NEET UG - Mendelian inheritance - laws of inheritance, monohybrid and dihybrid crosses Online Test (MCQ Quiz)

1. Who is widely recognized as the 'Father of Genetics' for his pioneering work on pea plants?

A) Charles Darwin B) Gregor Mendel C) James Watson D) Francis Crick

2. Gregor Mendel conducted his experiments on which plant species?

A) Drosophila melanogaster (Fruit fly) B) Pisum sativum (Garden pea) C) Oryza sativa (Rice) D) Zea mays (Maize)

3. Which of Mendel's laws states that during gamete formation, the alleles for each gene segregate independently from each other?

A) Law of Dominance B) Law of Segregation C) Law of Independent Assortment D) Law of Reciprocal Crosses

4. The Law of Segregation, proposed by Mendel, is based on the observation that:

A) Dominant alleles always mask recessive alleles. B) Factors (alleles) segregate during gamete formation and reunite during fertilization. C) Genes located on the same chromosome are inherited together. D) The expression of one gene is not affected by the expression of another gene.

5. In a monohybrid cross, Mendel studied the inheritance of how many contrasting traits at a time?

A) One B) Two C) Three D) Four

6. What is the phenotypic ratio observed by Mendel in the F2 generation of a monohybrid cross for a single trait?

A) 1:1 B) 3:1 C) 9:3:3:1 D) 1:2:1

7. The genotypic ratio observed by Mendel in the F2 generation of a monohybrid cross is typically:

A) 3:1 B) 1:1 C) 1:2:1 D) 9:3:3:1

8. If 'T' represents the allele for tallness and 't' represents the allele for dwarfness in pea plants, what is the genotype of a homozygous recessive individual?

A) TT B) Tt C) tt D) T

9. In a monohybrid cross between two heterozygous individuals (e.g., Tt x Tt), what proportion of the offspring are expected to be homozygous dominant?

A) 1/4 B) 1/2 C) 3/4 D) 1/3

10. Which term describes an individual with two identical alleles for a specific gene?

A) Heterozygous B) Homozygous C) Dominant D) Recessive

11. The first filial (F1) generation in Mendel's monohybrid cross between pure breeding tall (TT) and pure breeding dwarf (tt) plants showed:

A) All tall plants B) All dwarf plants C) A mixture of tall and dwarf plants in a 1:1 ratio D) Intermediate height plants

12. Mendel's Law of Dominance states that:

A) Alleles segregate independently. B) In a heterozygous pair, one allele masks the expression of the other. C) Gametes are pure for a character. D) Both alleles in a heterozygote express themselves.

13. A dihybrid cross involves the study of inheritance of:

A) One trait B) Two traits C) Three traits D) Multiple traits

14. In pea plants, Mendel studied the inheritance of seed shape (round vs. wrinkled) and seed color (yellow vs. green). This is an example of a:

A) Monohybrid cross B) Dihybrid cross C) Trihybrid cross D) Test cross

15. What is the characteristic phenotypic ratio observed by Mendel in the F2 generation of a dihybrid cross between plants with genotype RRYY and rryy?

A) 3:1 B) 1:2:1 C) 9:3:3:1 D) 1:1:1:1

16. In a dihybrid cross, if the alleles for seed shape are R (round) and r (wrinkled), and alleles for seed color are Y (yellow) and y (green), what is the genotype of a plant that is homozygous dominant for both traits?

A) RrYy B) RRYY C) rryy D) RRyy

17. If a plant has the genotype RrYy, how many different types of gametes can it produce based on Mendel's principles?

A) 2 B) 4 C) 6 D) 8

18. The F1 generation of a dihybrid cross (e.g., RRYY x rryy) typically exhibits:

A) All combinations of traits B) Only parental combinations C) The dominant phenotype for both traits D) The recessive phenotype for both traits

19. A test cross is performed to determine the genotype of an individual exhibiting a dominant phenotype. It involves crossing the individual with:

A) A homozygous dominant individual B) A heterozygous individual C) A homozygous recessive individual D) Another individual with the same dominant phenotype

20. If the offspring of a test cross show a 1:1 ratio of dominant to recessive phenotypes, the genotype of the parent with the dominant phenotype was:

A) Homozygous dominant B) Homozygous recessive C) Heterozygous D) Cannot be determined

21. What is the term for the observable physical characteristics of an organism, such as flower color or seed shape?

A) Genotype B) Phenotype C) Allele D) Karyotype

22. An allele that is always expressed when present, masking the effect of a recessive allele, is called:

A) Recessive B) Codominant C) Dominant D) Epistatic

23. An allele whose expression is completely masked by a dominant allele in a heterozygote is termed:

A) Dominant B) Homozygous C) Recessive D) Wild type

24. What term describes a pair of genes or alleles that are different for a particular trait?

A) Homozygous B) Heterozygous C) Dominant D) Recessive

25. Mendel's experiments demonstrated that inheritance is:

A) Blended B) Particulate C) Continuous D) Random

26. The P (Parental) generation in Mendel's experiments consisted of:

A) Hybrid individuals B) Pure breeding individuals C) Individuals with intermediate traits D) Mutated individuals

27. Which of the following is NOT one of the seven traits Mendel studied in pea plants?

A) Seed shape B) Flower position C) Leaf color D) Stem length

28. If a trait is controlled by a dominant allele, an individual with which genotype(s) would express that trait?

A) Only homozygous dominant B) Only heterozygous C) Homozygous dominant and heterozygous D) Only homozygous recessive

29. Mendel's work laid the foundation for understanding genetic variation and inheritance patterns, which is crucial for:

A) Understanding evolution B) Developing new agricultural crops C) Diagnosing genetic disorders D) All of the above

30. In a dihybrid cross involving two independently assorting genes, what is the probability of obtaining an offspring with the genotype rryy from parents with genotype RrYy?

A) 1/16 B) 1/4 C) 1/8 D) 9/16

31. The Punnett square is a graphical representation used to predict the genotypes of offspring from a cross. It was developed by:

A) Gregor Mendel B) Reginald C. Punnett C) Thomas Hunt Morgan D) Alfred Sturtevant

32. If an allele is present on the X chromosome but not on the Y chromosome, it is considered:

A) Autosomal B) Sex-linked C) Mitochondrial D) Mendelian

33. Which of Mendel's laws is violated if two genes are located very close to each other on the same chromosome?

A) Law of Dominance B) Law of Segregation C) Law of Independent Assortment D) Law of Uniformity

34. The phenomenon where one gene controls the expression of another gene is known as:

A) Pleiotropy B) Epistasis C) Codominance D) Incomplete dominance

35. What is pleiotropy?

A) One gene influencing multiple traits B) Multiple genes influencing one trait C) Alleles showing intermediate expression D) Both alleles being fully expressed

36. In incomplete dominance, the heterozygous phenotype is:

A) Identical to the dominant phenotype B) Identical to the recessive phenotype C) An intermediate of the two parental phenotypes D) A blend of both parental phenotypes

37. Codominance is a condition where:

A) One allele masks the other B) Both alleles in a heterozygote are fully and simultaneously expressed C) The heterozygote shows an intermediate phenotype D) One gene affects multiple traits

38. Human blood group AB is an example of:

A) Incomplete dominance B) Codominance C) Complete dominance D) Epistasis

39. Mendel's success was partly due to his careful selection of:

A) A large number of traits to study B) Animals for his experiments C) A suitable experimental organism with distinct traits D) Statistical analysis methods

40. The alleles for tallness (T) and dwarfness (t) are found on:

A) Sex chromosomes B) Autosomes C) Mitochondrial DNA D) Plasmids

41. If a trait exhibits complete dominance, what is the phenotypic ratio in the F2 generation of a monohybrid cross between two heterozygotes?

A) 1:1 B) 2:1 C) 3:1 D) 1:2:1

42. The genotype of a plant with wrinkled yellow seeds, assuming independent assortment and standard dominance where R is round and r is wrinkled, Y is yellow and y is green, would be:

A) RRYY B) RrYy C) rrYY D) rryy

43. What is the term for the specific location of a gene on a chromosome?

A) Allele B) Genotype C) Locus D) Phenotype

44. Mendel's Law of Segregation is analogous to:

A) The independent behavior of homologous chromosomes during meiosis I. B) The separation of sister chromatids during meiosis II. C) The replication of DNA before cell division. D) The formation of gametes.

45. Which of the following crosses would result in offspring with only one type of phenotype if complete dominance is assumed?

A) Tt x tt B) TT x tt C) Tt x Tt D) tt x tt

46. In a dihybrid cross, the parental generation genotypes are typically:

A) Heterozygous for both traits B) Homozygous dominant for one trait and homozygous recessive for the other C) Pure breeding for contrasting traits D) Homozygous recessive for both traits

47. The reason Mendel's Law of Independent Assortment is not universally applicable is due to:

A) Incomplete dominance B) Sex-linked inheritance C) Linkage D) Polygenic inheritance

48. What is the probability of obtaining a heterozygous offspring (Rr) from a cross between a homozygous dominant parent (RR) and a homozygous recessive parent (rr)?

A) 0 B) 1/4 C) 1/2 D) 1

49. A monohybrid cross with incomplete dominance between two heterozygotes would yield which phenotypic ratio in the F2 generation?

A) 3:1 B) 1:2:1 C) 9:3:3:1 D) 1:1

50. The concept of 'factors' or 'genes' being passed from parents to offspring, which maintain their identity through generations, was introduced by:

A) Charles Darwin B) Gregor Mendel C) Hugo de Vries D) William Bateson

Mendelian inheritance - laws of inheritance, monohybrid and dihybrid crosses - Online Test

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