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प्रश्न
Explain the mechanism of hereditary changes.
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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.
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संबंधित प्रश्न
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.
Mendel crossed tall pea plants with dwarf pea plants in his experiment. Write his observations giving reason on the F1 and F2 generations.
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:
With the help of two suitable examples, explain why certain experiences and traits earned by people during their lifetime are not passed on to their next generations. When can such traits be passed on?
A Mendelian experiment consisted of breeding pea plants bearing violet flowers with pea plants bearing white flowers. What will be the result in F1 progeny?
What constitutes the link between one generation and the next?
What type of plants were used by Mendel for conducting his experiments on inheritance?
The gene for red hair is recessive to the gene for black hair. What will be the hair colour of a person if he inherits a gene for red hair from his mother and a gene for black hair from his father?
What will you get in the F1 and F2 generations in the following cross?
Pure tall pea plant × Pure dwarf pea plant
What sizes of plants are produced if both parents have genes Tt?
A cross between two individuals results in a ratio of 9 : 3 : 3 : 1 for four possible phenotypes of progeny. This is an example of a ______.
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 red-haired woman marries a brown-haired man, and all the children are brown haired. Explain this genetically.
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.
Hereditary characters are transferred from parents to offspring by ______ hence they are said to be structural and functional units of heredity.
Why are the traits acquired during the life time of an individual not inherited? Explain.
A cross between a tall plant (TT) and short pea plant (tt) resulted in progeny that were all tall plants because
In human males all the chromosomes are paired perfectly except one. This/these unpaired chromosome is/are
- large chromosome
- small chromosome
- Y-chromosome
- X-chromosome
What are the components of the DNA molecule?
