What key advantage did Mendel have due to the large sampling size in his experiments?
Mendel's experiments had a large sampling size, which gave greater credibility to the data that he collected and helped him derive general rules of inheritance rather than unsubstantiated ideas.
Question 82 of 519
📘 CLASS XII
What are the dominant and recessive traits for flower colour in pea plants studied by Mendel?
According to the table of contrasting traits studied by Mendel, for the character of flower colour, Violet was the dominant trait and White was the recessive trait.
Question 83 of 519
📘 CLASS XII
According to the Law of Segregation, a heterozygous parent (Tt) produces:
The Law of Segregation states that during gamete formation, the alleles of a pair segregate. A heterozygous parent produces two kinds of gametes, each having one allele with equal proportion.
Question 84 of 519
📘 CLASS XII
Which of the following traits in garden pea was not studied by Mendel?
Answer: (d) Seed number
Explanation: Mendel studied seven traits in pea plants:
1. Seed shape
2. Seed color
3. Flower color
4. Pod shape
5. Pod color
6. Flower position
7. Stem height
Seed number was not one of the traits studied by Mendel.
Question 85 of 519
📘 CLASS XII
When genes are located close together on the same chromosome, they tend to be:
Answer: (b) Inherited together
Explanation: Genes that are close to each other on the same chromosome show linkage
and are usually inherited together during meiosis because the chance of crossing over between them is very low.
The closer the genes, the stronger the linkage.
Question 86 of 519
📘 CLASS XII
The frequency of recombination between linked genes is used to measure:
Answer: (c) Genetic map distance
Explanation: The frequency of recombination between two linked genes is directly proportional to
the physical distance between them on a chromosome. It is used to construct genetic linkage maps,
where 1% recombination frequency is equivalent to 1 map unit or 1 centimorgan (cM).
Question 87 of 519
📘 CLASS XII
Down’s syndrome in humans is caused by:
Answer: (a) Trisomy of chromosome 21
Explanation: Down’s syndrome is a genetic disorder caused by the presence of an extra copy of
chromosome 21 (trisomy 21). Individuals exhibit characteristic facial features, short stature,
mental retardation, and developmental delays. It occurs due to nondisjunction during gamete formation.
Question 88 of 519
📘 CLASS XII
In Mendel's monohybrid cross between true-breeding tall and dwarf pea plants, what was the phenotype of the F1 generation?
In Mendel's monohybrid cross between tall (TT) and dwarf (tt) pea plants, all the F1 progeny were tall because the T (tall) allele is dominant over t (dwarf).
Question 89 of 519
📘 CLASS XII
In Mendel's monohybrid cross, what was the phenotypic ratio observed in the F2 generation?
When Mendel self-pollinated the tall F1 plants, he found that in the F2 generation, 3/4th of the plants were tall and 1/4th were dwarf, expressing a phenotypic ratio of 3:1.
Question 90 of 519
📘 CLASS XII
What term did Mendel use for the "things" that were stably passed down from parent to offspring and are now called genes?
Based on his observations, Mendel proposed that something was being stably passed down, unchanged, from parent to offspring. He called these things ‘‘factors’’, which we now call genes.
