Advertisements
Advertisements
प्रश्न
Why are the traits acquired during the life time of an individual not inherited? Explain.
Advertisements
उत्तर
Acquired traits (like muscle built by exercise or a scar) arise from environmental effects on an individual’s somatic cells and do not change the DNA of gametes. Because inheritance depends on alterations in the germ line, somatic modifications are not passed to offspring, this is the Weismann barrier separating soma and germ line. Lamarck’s idea that acquired characters are inherited was thus disproved; only genetic changes (mutations) or stable germ-line epigenetic marks can be inherited, and these are rare. Therefore, traits acquired during life are generally not transmitted to the next generation.
संबंधित प्रश्न
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.
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.
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?
Give the contrasting traits of the following characters in pea plant and mention which is dominant and which is recessive:
Yellow seed
Why did Mendel choose pea plants for conducting his experiments on inheritance?
When two parents are crossed, the offspring are referred to as :
recessives
test cross
F1 generation
F2 generation
What are the possible blood groups likely to be inherited by children born to a group A mother and a group B father? Explain your reasoning.
One of the following traits of the parents cannot be passed on to their future generations. This trait is:
Define Heredity. Give two examples.
Mendel crossed pea plants with two pairs of contrasting characters.
| RRYY | × |
rryy |
| Round, Yellow | Wrinkled, Green |
He observed 4 types of combinations in F2 generation. Which of the combinations were new? Write the conclusion drawn by this experiment.
