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Class 10 Heredity worksheet
CBSE Science. Mendel's crosses worked out, ratios, gametes, sex determination, probability. Every sheet has 20 questions in three sections and an answer key, and the numbers change every time.
Sample questions
Real questions from this chapter, as the app sets them. Tap Answer to see the answer and working.
Section A · multiple choice
- 1.
In pea plants (T = tall, t = dwarf), the cross TT × tt gives plants in the ratio:
- all tall
- 3 tall : 1 dwarf
- 1 tall : 3 dwarf
- 1 tall : 1 dwarf
Answer
(a) all tall
offspring: all Tt
- 2.
A pure-breeding plant with round seeds is crossed with a pure-breeding plant with wrinkled seeds, and the F₁ plants are self-pollinated. Out of 104 F₂ seeds, about how many are round?
- 52
- 104
- 26
- 78
Answer
(d) 78
round : total = 3 : 4
- 3.
Mendel carried out his experiments on:
- maize
- the fruit fly
- the garden pea
- mice
Answer
(c) the garden pea
Section B · short answer
- 4.
In pea plants, I = inflated, i = constricted. Cross Ii with Ii. Give the genotypes of the offspring with their ratio, and the ratio of the phenotypes.
Answer
Genotypes II : Ii : ii = 1 : 2 : 1; phenotypes 3 inflated : 1 constricted
gametes I, i × I, i
- 5.
Pea plants IIAA × iiaa are crossed (I = inflated, i = constricted; A = axial, a = terminal) and the F₁ plants are self-pollinated. Out of 896 F₂ plants, how many of each kind are expected?
Answer
inflated pods and axial flowers: 504; inflated pods and terminal flowers: 168; constricted pods and axial flowers: 168; constricted pods and terminal flowers: 56
9 : 3 : 3 : 1, each part = 896 ÷ 16 = 56
Section C · long answer
- 6.
Explain Mendel's monohybrid cross between a tall and a dwarf pea plant up to the F₂ generation.
Answer
TT (tall) × tt (dwarf): all F₁ plants are Tt and tall. F₁ plants self-pollinate: Tt × Tt gives TT, Tt, Tt, tt. F₂ genotype ratio 1 : 2 : 1; phenotype ratio 3 tall : 1 dwarf. The dwarf trait, hidden in F₁, reappears in F₂.
Fresh sheets for your child
In the app, every Heredity sheet is new: the app remembers the questions your child has already had and leaves them out. Print the sheet as a PDF, or use notebook mode and write the answers in a notebook.
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