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प्रश्न
Why did Mendel choose pea plants for conducting his experiments on inheritance?
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उत्तर
Mendel chose pea plants for studying inheritance because of the following reasons:
- Pea plants had a number of clear cut differences which were easy to tell apart. For example, some pea plants were 'tall' whereas others were 'dwarf'.
- They were self pollinating plants.
- Many generations of pea plants can be produced in a comparatively short time span and their study is much simpler than that of animals.
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संबंधित प्रश्न
How do Mendel’s experiments show that the traits may be dominant or recessive?
Outline a project which aims to find the dominant coat colour in dogs.
How did Mendel explain that it is possible that a trait is inherited but not expressed in an organism?
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.
Fill in the following blank with suitable word .
In pea plants, the gene for dwarfness is ..............whereas that for tallness is ............ .
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.
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 tall plants which always produced tall offspring
How do Mendel's experiments show that traits are inherited independently?
A pregnant woman has an equal chance of her baby being blood group A or blood group AB. Which one of the following shows the possible genotypes of the woman and the father of her child?
(a) IA IA and IB IO
(b) IA IB and IB IO
(c) IA IO and IB IO
(d) IA IB and IA IO
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
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
The term 'father of genetics' is used for the scientist :
(a) Morgan
(b) Mendel
(c) Darwin
(d) Marie Curie
Hereditary characters are transferred from parents to offspring by ______ hence they are said to be structural and functional units of heredity.
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?
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.
