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Biology - Principles of Inheritance and Variation

Practise 14 IAT (IISER) previous year questions on Principles of Inheritance and Variation, compiled from papers spanning 2017 to 2026. Each question is pulled directly from the actual exam paper it appeared in, so you're practising in the exact style and difficulty IAT (IISER) tests.

Principles of Inheritance and Variation has been asked in 8 of the 9 years of IAT (IISER) papers analysed (2017–2026), with 14 questions in all. 7% of them were easy, 86% moderate and 7% tough. Most of its questions came from 2022, with 4 questions that year. In the last three years (2023–2026) it had 4 questions across 3 papers, about 1.3 per paper.

The chapter's 7 topics are not weighted equally: Genetic Disorders (4 questions, 29%), Mendel's Work and Results (4 questions, 29%), and Sex Determination (2 questions, 14%) have been asked the most. Genetic Disorders has also led over the last five years, with 3 questions. Chromosome Theory of Inheritance has produced the most tough questions (1).

  1. 1The following pedigree diagram shows the inheritance of a rare genetic disorder in a family (filled shapes depict affected individuals). Whi2026Genetic Disorders
  2. 2Two double heterozygous plants (PpQq), derived from two different pairs of true-breeding parents of unknown genotype, produce gametes in the2025Chromosome Theory of Inheritance
  3. 3Honey bee males are haploid and females are diploid. Which one of the following statements is INCORRECT about honey bees?2025Sex Determination
  4. 4The following pedigree diagram shows the inheritance of a rare genetic disorder (filled shapes depict affected individuals). Which of the fo2024Genetic Disorders
  5. 5In an island with 10,000 individuals, four have sickle cell anemia, a recessive autosomal disease. Assuming that the locus is in Hardy-Weinb2023Mendel's Work and Results
  6. 6The following pedigree chart shows the inheritance of a genetic disorder. I-2 and III-2 are the only affected individuals. Which one of the 2023Genetic Disorders
  7. 7In a given species of flowering plant, the colour of the seeds is exclusively determined by the colour of its seed coat. Seed coat colour in2022Mendel's Work and Results
  8. 8A single point mutation in gene ' X ' results in breathing difficulty, hypertension as well as partial sterility. Which among the following 2022Mutation
  9. 9In a cross between individuals of the genotypes PpQQRrSS and ppqqRrSS, what will be the expected number of progenies with the genotype ppQQR2022Mendel's Laws of Inheritance
  10. 10Nine percent of a population cannot taste a certain food item because of a recessive allele of the gene IAT. Assuming the population is in H2022Mendel's Work and Results
  11. 11A hypothetical plant species shows two flower colour phenotypes - red and white. Red is dominant over white. In a population, this flower co2020Mendel's Work and Results
  12. 12The diagram below represents the pedigree of a certain genetic disease (affected individuals are shaded). What is the mode of inheritance of2019Genetic Disorders
  13. 13Haplo-diploid insects have diploid females from fertilized eggs but haploid males from unfertilized ones. Such a haploid male with red eyes 2018Sex Determination
  14. 14Which one of the following pairs of genotype and phenotype ratios will be obtained in F2 generation for Snapdragon plants exhibiting incompl2017Incomplete Dominance

Frequently Asked Questions

1.How many questions are available for Principles of Inheritance and Variation?

This chapter includes 14 questions compiled from IAT (IISER) papers spanning 2017 to 2026.

2.Are these questions only from IAT (IISER), or from other exams too?

These are IAT (IISER) questions specifically for the Principles of Inheritance and Variation chapter. Questions from other exams like JEE Main or NTA Abhyas (JEE Main) are organised separately under their respective exam sections.

3.Is Principles of Inheritance and Variation an important chapter for IAT (IISER) Biology?

Principles of Inheritance and Variation has appeared in 9 of the 10 years of IAT (IISER) papers covered here, with 14 questions across 9 papers - about 2 per paper it appears in.

4.What is the difficulty level of Principles of Inheritance and Variation questions in IAT (IISER)?

Of the 14 questions analysed for this chapter, 7% are easy, 86% moderate and 7% tough. 2022 had the most, with 4 questions.

5.Which topics in Principles of Inheritance and Variation should I focus on?

These topics have carried the most weightage in Principles of Inheritance and Variation:

  • Genetic Disorders - 4 questions (29%)
  • Mendel's Work and Results - 4 questions (29%)
  • Sex Determination - 2 questions (14%)
  • Chromosome Theory of Inheritance has produced the most tough questions (1).
6.Is Principles of Inheritance and Variation's weightage in IAT (IISER) going up or down?

Across all 9 papers analysed, Principles of Inheritance and Variation has averaged about 1.6 questions per paper. In the last three years (2023–2026), that average has stayed about the same, at about 1.3 questions per paper. Use the year-wise numbers on this page for the exact trend before you decide how much time to give it.