Advertisements
Advertisements
प्रश्न
Explain the mechanism of hereditary changes.
Advertisements
उत्तर
- Mutation: A sudden change in parental DNA can cause a mutation. This leads to changes in hereditary characters.
- Crossing over during meiosis: During meiosis, crossing over takes place between homologous chromosomes. It produces new combinations of genetic information. As a result, the haploid gametes formed carry altered hereditary characters.
APPEARS IN
संबंधित प्रश्न
Define heredity.
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
In the F2 generation of a cross, progeny having different traits are produced in the ratio 3 : 1. State whether it is a monohybrid cross or a dihybrid cross? Give one example of such a cross.
What sizes of plants are produced if both parents have genes Tt?
How do Mendel's experiments show that traits may be dominant or recessive?
In the human blood grouping, the four basic blood types are type A, type B, type AB, and type O. The blood proteins A and B are :
(a) simple dominant and recessive traits
(b) incomplete dominant traits
(c) codominant traits
(d) sex-linked traits
The visible characteristic in an organism is known as :
(a) prototype
(b) stereotype
(c) phenotype
(d) genotype
Which of the following statement is incorrect?
(a) for every hormone there is a gene
(b) for every protein there is a gene
(c) for production of every enzyme there is a gene
(d) for every type of fat there is a gene
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?
The farmers have been cultivating a food plant X for over two thousand years and have produced as many as five entirely different looking vegetables A, B, C, D and E from it.
(a) What could the plant X be?
(b) What are A, B, C, D and E?
(c) What is the process of evolution involved in this example known as?
If we pure-bred tall (dominant) pea plant with pure-bred dwarf (recessive) pea plant we will get pea plants of F1 generation. If we now self-cross the pea plant of F1 generation, then we obtain pea plants of F2 generation.
(a) What do the plants of F2 generation look like?
(b) State the ratio of tall plants to dwarf plants in F2 generation.
(c) State the type of plants not found in F1 generation but appeared in F2 generation, mentioning the reason for the same.
Answer the following question.
Name the plant Mendel used for his experiment. What type of progeny was obtained by Mendel in F1 and F2 generations when he crossed the tall and short plants? Write the ratio he obtained in F2 generation plants.
Why are the traits acquired during the life time of an individual not inherited? Explain.
Who is the pioneer of modern genetics?
____________ refers to the transmission of genetic information from parental generation to next generation.
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?
Name the following:
The basic units of heredity.
