English Medium कक्षा १० - CBSE Important Questions

Explain Mendel’s law of independent inheritance. Give one example.

Mendel, in one of his experiments with pea plants, crossed a variety of pea plant having round seeds with one having wrinkled seeds. State Mendel’s observations giving reasons of F₁ and F₂ progeny of this cross. Also, list any two contrasting characters, other than round seeds of pea plants that Mendel used in his experiments.

What is genetics?

Two pea plants - one with round yellow seeds (RRYY) and another with wrinkled green (rryy) seeds produce F1 progeny that have round, yellow (RrYy) seeds.

When F1 plants are self-pollinated, which new combination of characters is expected in F2 progeny? How many seeds with these new combinations of characters will be produced when a total 160 seeds are produced in F2 generation? Explain with reason.

Sahil performed an experiment to study the inheritance pattern of genes. He crossed tall pea plants (TT) with short pea plants (tt) and obtained all tall plants in F1 generation.

What will be set of genes present in the F1 generation?

Sahil performed an experiment to study the inheritance pattern of genes. He crossed tall pea plants (TT) with short pea plants (tt) and obtained all tall plants in F1 generation.

Give a reason why only tall plants are observed in F1 progeny.

Sahil performed an experiment to study the inheritance pattern of genes. He crossed tall pea plants (TT) with short pea plants (tt) and obtained all tall plants in F1 generation.

When F1 plants were self-pollinated, a total of 800 plants were produced. How many of these would be tall, medium height or short plants? Give the genotype of F2 generation.

Sahil performed an experiment to study the inheritance pattern of genes. He crossed tall pea plants (TT) with short pea plants (tt) and obtained all tall plants in F1 generation.

When F1 plants were cross-pollinated with plants having tt genes, a total of 800 plants were produced. How many of these would be tall, medium height or short plants? Give the genotype of F2 generation.

If a tall pea plant is crossed with a pure dwarf pea plant then, what percentage of F1 and F2 generation respectively will be tall?

The diagram shown below depicts pollination. Choose the options that will show a maximum variation in the offspring.

How are variations useful for species if there is drastic alteration in the niches?

Pooja has green eyes while her parents and brother have black eyes. Pooja’s husband Ravi has black eyes while his mother has green eyes and father has black eyes.

a. On the basis of the above given information, is the green eye colour a dominant or recessive trait? Justify your answer

b. What is the possible genetic makeup of Pooja’s brother’s eye colour?

c. What is the probability that the offspring of Pooja and Ravi will have green eyes? Also, show the inheritance of eye colour in the offspring with the help of a suitable cross.

OR

c. 50% of the offspring of Pooja’s brother are green eyed. With help of cross show how this is possible.

In the following figure showing a germinating gram seed, name the parts labelled as A, B and C:

Why is Part 'B' considered to be important during germination?

A cross between pea plant with white flowers (vv) and pea plant with violet flowers (VV) resulted in F₂ progeny in which ratio of violet (VV) and white (vv) flowers will be ______.

• Assertion: The probability of survival of an organism produced through sexual reproduction is more than that of an organism produced through asexual mode.
• Reason: Variations provide advantages to individuals for survival.

Figures (a) to (d) given below represent the type of ear lobes present in a family consisting of 2 children - Rahul, Nisha and their parents.

Excited by his observation of different types of ear lobes present in his family, Rahul conducted a survey of the type of ear lobes found {Figure (e) and (f)} in his classmates. He found two types of ear lobes in his classmates as per the frequency given below:

On the basis of the above data answer the following questions.

1. Which of the two characteristics - ‘free ear lobe’ or ‘attached ear lobe’ appears to be dominant in this case? Why?
2. Is the inheritance of the free ear lobe linked with the sex of the individual? Give a reason for your answer.
3. What type of ear lobe is present in father, mother, Rahul and his sister Nisha? Write the genetic constitution of each of these family members which explains the inheritance of this character in this family.
   (Gene for the Free ear lobe is represented by F and the gene for the attached ear lobe is represented by f for writing the genetic constitution).
   OR
   Suresh’s parents have attached ear lobes. What type of ear lobe can be seen in Suresh and his sister Siya? Explain by giving the genetic composition of all.

Mendel crossed pea plants with two pairs of contrasting characters.

He observed 4 types of combinations in F2 generation. Which of the combinations were new? Write the conclusion drawn by this experiment.

What does sign of power (+ve or –ve) indicate?

How unit of power related to focal length of a lens?

The shiny outer surface of a hollow sphere of aluminium of radius 50 cm is to be used as a mirror: 

 What will be the focal length of this mirror?