Advertisements
Advertisements
प्रश्न
Define Heredity. Give two examples.
उत्तर
- Heredity is the transmission of physical or mental traits from parents to offsprings.
- Example: Attached ear-lobes, Rolling tongue.
संबंधित प्रश्न
How do Mendel’s experiments show that the traits may be dominant or recessive?
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.
Name the information source for making proteins in the cells.
Mendel crossed tall pea plants with dwarf pea plants in his experiment. Write his observations giving reason on the F1 and F2 generations.
List any two contrasting characters other than height that Mendel used in his experiments in pea plants.
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?
State whether the following statement is true or false :
The sex of an infant is not a case of inheritance of characteristics.
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?
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?
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 is the genotype of dwarf plants which always produced dwarf offspring?
What is the genotype of tall plants which always produced tall offspring
Give the contrasting traits of the following characters in pea plant and mention which is dominant and which is recessive :
Round seed
Why did Mendel choose pea plants for conducting his experiments on inheritance?
How do Mendel's experiments show that traits are inherited independently?
When two parents are crossed, the offspring are referred to as :
recessives
test cross
F1 generation
F2 generation
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 ______
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..
If the ratio of each phenotype of the seeds of pea plants in the F2 generation is 9 : 3 : 3 : 1, it is known as :
(a) tetrahybrid ratio
(b) monohybrid ratio
(c) dihybrid ratio
(d) trihybrid ratio
In humans, if gene B gives brown eyes and gene b gives blue eyes. What will be the colour of eyes of the persons having the following combination of genes?
(a) Bb
(b) bb
(c) BB
Mendel first crossed pure-bred pea plants having round-yellow seeds with pure-bred pea plants having wrinkled-green seeds and found that only round-yellow seeds were produced in the F1 generation. When F1generation pea plants having round-yellow seeds were cross-bred by self pollination, then peas having round-yellow seeds, round green seeds, wrinkled-yellow seeds and wrinkled-green seeds were produced. Mendel collected a total of 2160 seeds.
(a) What will be the number of (i) round green seeds (ii) wrinkled green seeds (iii) round yellow seeds, and (iv) wrinkled-yellow seeds?
(b) Which 'ratio' as established by Mendel have you made use of in answering the part (a) above?
List two differences in tabular form between dominant trait and recessive traits. What percentage/proportion of the plants in the F2 generation/progeny were round, in Mendel's cross between round and wrinkled pea plants?
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.
Explain the mechanism of hereditary changes.
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.
Hereditary characters are transferred from parents to offspring by ______ hence they are said to be structural and functional units of heredity.
What is genetics?
A cross between a tall plant (TT) and short pea plant (tt) resulted in progeny that were all tall plants because
If a round, green seeded pea plant (RR yy) is crossed with wrinkled, yellow seeded pea plant, (rr YY) the seeds produced in F1 generation are
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 ______.
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.
|
(a) Rahul's Father |
(b) Rahul |
(c) Rahul's Mother |
(d) Rahul's sister Nisha |
|
(e) |
(f) |
||
| Types of ear lobes | |||
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:
| Sex | Free | Attached |
| Male | 36 | 14 |
| Female | 31 | 19 |
On the basis of the above data answer the following questions.
- Which of the two characteristics - ‘free ear lobe’ or ‘attached ear lobe’ appears to be dominant in this case? Why?
- Is the inheritance of the free ear lobe linked with the sex of the individual? Give a reason for your answer.
- 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.
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.
