English Medium कक्षा १० - CBSE Question Bank Solutions for Science

How do Mendel’s experiments show that the traits may be dominant or recessive? 

"A trait may be inherited, but may not be expressed." Justify this statement with the help of a suitable example.

How do Mendel's experiment show that traits are inherited independently?

In one of his experiments with pea plants, Mendel observed that when a pure tall pea plant is crossed with a pure dwarf pea plant in the first generation, F₁, only tall plants appear.

(a) What happens to the traits of the dwarf plants in this case?

(b) When the F₁-​generation plants were self-fertilised, he observed that in the plants of the second generation, F₂, both tall plants and dwarf plants were present. Why it happened? Explain briefly.

How did Mendel interpret his results to show that traits may be dominant or recessive? Describe briefly.

In a monohybrid cross between tall pea plants (TT) and short pea plants (tt), a scientist obtained only tall pea plants (Tt) in the F₁ generation. However, on selfing the F₁ generation pea plants, he obtained both tall and short plants in F₂ generation. On the basis of above observations with other angiosperms also, can the scientist arrive at a law? If yes, explain the law. If not, give justification for your answer.

A pea plant with blue colour flower denoted by BB is cross-bred with a pea plant with white flower denoted by ww.

(a) What is the expected colour of the flowers in their F₁ progeny?

(b) What will be the percentage of plants bearing white flower in F₂ generation, when the flowers of F₁ plants were selfed?

(c) State the expected ratio of the genotype BB and Bw in the F₂ progeny.

What is a gene?

Define heredity.

A cross was made between pure breeding pea plants one with round and green seeds and the other with wrinkled and yellow seeds.

(a) Write the phenotype of F₁ progeny. Give reason for your answer.

(b) Write the different types of F₂ progeny obtained along with their ration when F₁ progeny was selfed.

Name the information source for making proteins in the cells.

Mendel crossed tall pea plants with dwarf pea plants in his experiment. Write his observations giving reason on the F₁ and F₂ generations.

List any two contrasting characters other than height that Mendel used in his experiments in pea plants.

Mendel in one of his experiments with pea plants crossed a variety having round seed with one having wrinkled seeds. Write his observations, giving reasons, of F₁ and F₂ progeny

List any two contrasting characters other than roundness of pea plants that Mendel used in his experiments with pea plants.

A man with blood group A marries a woman with blood group O and their daughter has blood group O. Is this information enough to tell you which of the traits – blood group A or O – is dominant? Why or why not?

A Mendelian experiment consisted of breeding tall pea plants bearing violet flowers with short pea plants bearing white flowers. The progeny all bore violet flowers, but almost half of them were short. This suggests that the genetic make-up of the tall parent can be depicted as:

A study found that children with light-coloured eyes are likely to have parents with light-coloured eyes. On this basis, can we say anything about whether the light eye colour trait is dominant or recessive? Why or why not?

Outline a project which aims to find the dominant coat colour in dogs.

How is the equal genetic contribution of male and female parents ensured in the progeny?