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प्रश्न
Write advantages of science of heredity.
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उत्तर
The advantages of the science of heredity are as follows:
- Diagnosis of diseases.
- Treatment and prevention of heredity disorders.
- Production of hybrid varieties of animals and plants.
- Industrial processes in which microbes are used.
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संबंधित प्रश्न
"A trait may be inherited, but may not be expressed." Justify this statement with the help of a suitable example.
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.
Define heredity.
List any two contrasting characters other than roundness of pea plants that Mendel used in his experiments with pea plants.
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:
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?
What constitutes the link between one generation and the next?
Name the first scientist who studied the inheritance of traits from one generation to the next.
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?
A man having blood group O marries a woman having blood group B and they have a daughter. What will be the blood group of the daughter?
Using height (tallness/dwarfness) of a plant as an example, show that genes control the characteristics or traits in an organism.
What will you get in the F1 and F2 generations in the following cross?
Pure tall pea plant × Pure dwarf pea plant
It it an example of monohybrid cross or dihybrid cross?
What sizes of plants are produced if both parents have genes Tt?
Give the contrasting traits of the following characters in pea plant and mention which is dominant and which is recessive:
Yellow seed
Give the contrasting traits of the following characters in pea plant and mention which is dominant and which is recessive :
Round seed
How do Mendel's experiments show that traits are inherited independently?
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 ______
For his experiments on heredity, Mendel used :
papaya plants
potato plants
pea plants
pear plants
In order to ensure that he had pure-breeding plants for his experiments, Mendel :
(a) cross-fertilised each variety with each other
(b) let each variety self fertilise for several generations
(c) removed the female parts of the plants
(d) removed the male parts of the plants.
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 following results were obtained by a scientist who crossed the F1 generation of pure-breeding parents for round and wrinkled seeds.
| Dominant trait | Recessive trait | No. of F2 offspring |
| Round seeds | Wrinkled seeds | 7524 |
From these results, it can be concluded that the actual number of round seeds he obtained was ______
The visible characteristic in an organism is known as :
(a) prototype
(b) stereotype
(c) phenotype
(d) genotype
Select the statements that describe characteristics of genes :
(i) genes are specific sequences of bases in a DNA molecule.
(ii) a gene does not code for proteins.
(iii) in individuals of a given species, a specific gene is located on a particular chromosome.
(iv) each chromosome has only one gene..
Pure-bred pea plants A are crossed with pure-bred pea plants B. It is found that the plants which look like A do not appear in F1 generation but re-emerge in F2 generation. Which of the plants A and B are : (i) tall, and (ii) dwarf? Give reason for your answer.
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 person first crossed pure-bred pea plants having round-yellow seeds with pure-bred pea plants having wrinkled-green seeds and found that only A-B type of seeds were produced in the F1 generation. When F1generation pea plants having A-B type of seeds were cross-bred by self-pollination, then in addition to the original round-yellow and wrinkled-green seeds, two new varieties A-D and C-B type of seeds were also obtained.
(a) What are A-B type of seeds?
(b) State whether A and B are dominant traits or recessive traits.
(c) What are A-D type of seeds?
(d) What are C-B type of seeds?
(c) Out of A-B and A-D types of seeds, which one will be produced in (i) minimum numbers, and (ii) maximum numbers, in the F2 generation?
Pure-bred round-yellow pea seeds have genotype RRYY and the pure-bred wrinkled-green pea seeds have genotype rryy. Keeping this in mind, write the phenotypes of the following genotypes of hybrid pea seeds :
(a) Rryy
(b) rrYy
(c) rrYY
(d) RrYy
(e) RRyy
One of the following traits of the parents cannot be passed on to their future generations. This trait is :
(a) cleft chin
(b) pointed chin
(c) scarred chin
(d) broad chin
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.
Who is the pioneer of modern genetics?
Two pink coloured flowers on crossing resulted in 1 red, 2 pink and 1 white flower progeny. The nature of the cross will be
A cross between a tall plant (TT) and short pea plant (tt) resulted in progeny that were all tall plants because
What are the components of the DNA molecule?
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?
Rewrite the correct form of the statement by changing the first or last word only:
The inheritable feature of an organism is termed as heredity.
