Law of Dominance

Q.

Dihybrid ratio of Genotypic in F2 generation

Q.

What do you mean by dominant and recessive characters? Explain citing examples

Q.

Why is Mendels law of dominance not always true?

Q.

Which among the following statements is/are correct with respect to the law of dominance?

A. Each character is controlled by pair of discrete units called factors.

B. In a dissimilar pair of factors one is dominant and the other is recessive.

C. It explains the expression of one trait in $F_1$ and both traits in $F_2$ generation.

D. Explains the proportion of phenotypes, 3:1 obtained in $F_2$ generation.

1. A & B only

2. C& D only

3. C &A only

4. A, B, C & D

Q.

RR( Red) Artirrhinum is crossed with the white (WW) one. Offspring RW are pink. This is an example of:

1. Incomplete dominance

2. Dominant-­recessive

3. Supplementary genes

4. Hybrid

Q. Which one of the following was not the outcome of Mendel’s experiments?

1. Dominant trait
2. Factors reside in chromosomes
3. Segregation of factors
4. Independent assortment

Q.

Give the pair of contrasting traits of the following characters in the pea plant and mention which is dominant and recessive:-

1. yellow seed
2. round seed

Q.

Why law of segregation is universally accepted?

Q.

Define the following term:

Heterozygous condition

Q.

State Mendels Law of Dominance.

Q. How do Mendel's experiments show that the
(a) traits may be dominant or recessive,
(b) traits are inherited independently?

Q. Explain with an example how traits get expressed?

Q. Which mendelian idea is depicted by a cross in which the $F_1$ generation resembles both the parents?

1. Codominance
2. Inheritance of one gene
3. Incomplete dominance
4. Law of dominance

Q. A student makes a monohybrid cross between TT and tt plants, where T is dominant and t is recessive. Identify the correct statements on the basis of the information given.

Statement 1: Recessive traits are expressed in both ${\text{F}}_1$ and ${\text{F}}_2$ generation.

Statement 2: Recessive traits are expressed only in the absence of corresponding dominant trait in the offspring.

1. Only statement 2 is correct.
2. Both the statements are correct.
3. Only statement 1 is correct.
4. Both the statements are incorrect.

Q. Which one of the following was not the outcome of Mendel’s experiments?

1. Dominant trait
2. Factors reside in chromosomes
3. Segregation of factors
4. Independent assortment

Q. Mendel crossed a pure white flowered recessive pea plant with a dominant pure red flowered plant. The first generation of hybrids from the cross should show

1. 50% white flowers and 50% red flowers
2. All red flowered plants
3. 75% red flowered and 25% red flowered plants
4. All white flowered plants

Q. When a gene exists in more than one form, the different forms are termed as

1. Alleles
2. Heterozygotes
3. Genotypes
4. Complementary genes

Q. Choose the correct answer from the alternatives given.
Match column I with column II and select the correct option from the given codes.

	Column I		Column II
A.	Dihybrid test cross	(i)	9 : 3:3: 1
B.	Law of segregation	(ii)	Dihybrid cross
C.	Law of independent assortment	(iii)	1: 1: 1: 1
D.	ABO blood group in man	(iv)	Purity of gametes
		(v)	Multiple allelism

1. A - (iii), B - (ii), C - (iv), D - (v)
2. A - (iii), B - (iv), C - (ii), D - (v)
3. A - (i), B - (iv), C - (ii), D - (v)
4. A - (ii), B - (v), C - (iii), D - (i)

Q. Give reasons for the appearance of new combinations of characters in $F_2$ progeny.

Q. Based on the observations of the monohybrid cross, Mendel postulated the law of which distinguished dominant and recessive characters.

1. dominance
2. recessiveness
3. segregation
4. assortment

Q. In F${}_2$ generation, the crossing of a homozygous tall plant with a homozygous dwarf would yield plants in the ratio of______________

1. Two tall and two dwarf
2. One homozygous tall, one homozygous dwarf and two heterozygous tall
3. All homozygous dwarf
4. All homozygous tall

Q.

The phenotype of $F_1$ progeny, when pure tall and dwarf plants are crossed together is _________.

1. 50% Tall and 50% dwarf plants

2. 100% dwarf plants

3. 75% Tall and 25% dwarf plants

4. 100% tall plants

Q. Do you think Mendel’s laws of inheritance would have been different if the characters that he chose were located on the same chromosome?

Q. Mendel observed 7 pairs of contrasting characters in Pisum sativum. One of the following is not a part of that. Find out.

1. Yellow and green seed colour
2. Tall and dwarf stem
3. Terminal and axial flower
4. Smooth and rough stem

Q. Which of the following depicts Mendel's dihybrid ratio?

1. 9 : 3 : 3 : 1
2. 3 : 1
3. 9 : 7
4. 15 : 1

Q. A pure breeding triangular fruit-bearing plant of Shepherd's Purse is crossed with the ovoid fruit-bearing plant. The ratio of two types of plants in $F_2$ generation would be

1. 3 : 1
2. 1 : 2 : 1
3. 13 : 3
4. 15 : 1

Q. State Mendel's law of dominance. (2 Marks)

Q. Mendel’s Law of independent assortment holds good for genes situated on the:

1. homologous chromosomes
   
2. non-homologous chromosomes
   
3. same chromosome
4. extranuclear genetic element