PYQ Vault
EbooksTutor

Case study on Mendel's experiments

This type of question, asked 4 times: 2022, 2023, 2024, 2026. All 4 questions below, oldest first.

Try each one first, then open its answer.

  1. Question 1 (case study, 4 parts)

    2022

    Mendel blended his knowledge of Science and mathematics to keep the count of the individuals exhibiting a particular trait in each generation. He observed a number of contrasting visible characters controlled in pea plants in a field. He conducted many experiments to arrive at the laws of inheritance.
    14 (a)
    What do the F1 progeny of tall plants with round seeds and short plants with wrinkled seeds look like ?
    14 (b)
    Name the recessive traits in above case.
    14 (c)
    Mention the type of the new combinations of plants obtained in F2 progeny along with their ratio, if F1 progeny was allowed to self pollinate.
    14 (c) OR
    If 1600 plants were obtained in F2 progeny, write the number of plants having traits : (i) Tall with round seeds (ii) Short with wrinkled seeds Write the conclusion of the above experiment.

  2. Question 2 (case study, 4 parts)

    2023

    In order to trace the inheritance of traits Mendel crossed pea plants having one contrasting character or a pair of contrasting characters. When he crossed pea plants having round and yellow seeds with pea plants having wrinkled and green seeds, he observed that no plants with wrinkled and green seeds were obtained in the F1\mathrm{F_1} generation. When the F1\mathrm{F_1} generation pea plants were cross-bred by self-pollination, the F2\mathrm{F_2} generation had seeds with different combinations of shape and colour also.
    38 (a)
    Write any two pairs of contrasting characteristics of pea plant used by Mendel other than those mentioned above.
    38 (b)
    Differentiate between dominant and recessive traits.
    38 (c)
    State the ratio of the combinations observed in the seeds of F2\mathrm{F_2} generation (in the above case). What do you interpret from this result ?
    38 (c) OR
    Given below is a cross between a pure violet flowered pea plant (V) and a pure white flowered pea plant (v). Diagrammatically explain what type of progeny is obtained in F1\mathrm{F_1} generation and F2\mathrm{F_2} generation : Pure violet flowered plant ×\times Pure white flowered plant. (V V) (v v)

  3. Question 3 (case study, 4 parts)

    2024

    Mendel worked out the rules of heredity by working on garden pea using a number of visible contrasting characters. He conducted several experiments by making a cross with one or two pairs of contrasting characters of pea plant. On the basis of his observations he gave some interpretations which helped to study the mechanism of inheritance.
    38 (i)
    When Mendel crossed pea plants with pure tall and pure short characteristics to produce F1\mathrm{F_1} progeny, which two observations were made by him in F1\mathrm{F_1} plants?
    38 (ii)
    Write one difference between dominant and recessive trait.
    38 (iii) (A)
    In a cross with two pairs of contrasting characters RRYY ×\times rryy (Round Yellow) (Wrinkled Green) Mendel observed 4 types of combinations in F2\mathrm{F_2} generation. By which method did he obtain F2\mathrm{F_2} generation ? Write the ratio of the parental combinations obtained and what conclusions were drawn from this experiment.
    38 (iii) (B)
    Justify the statement : “It is possible that a trait is inherited but may not be expressed.”

  4. Question 4 (case study, 4 parts)

    2026

    Mendel took garden pea plants with different characteristics, such as height to study the inheritance pattern of factors (genes). He crossed tall pea plant with short pea plant and obtained all the tall plants in the F1\mathrm{F_1} generation.
    15 (a)
    Why only tall pea plants were observed in F1\mathrm{F_1} progeny ?
    15 (b)
    By which method did Mendel obtain F2\mathrm{F_2} progeny ?
    15 (c) (i)
    Write one difference between dominant and recessive trait.
    15 (c) (ii)
    Write two observations made by Mendel about F1\mathrm{F_1} progeny.