Mendel's Dihybrid Experiments

Q.

Explain the law of dominance and explain the law of segregation giving examples of both..

Q.

How is DNA inherited from each parent?

Q. In Mendel's experiments with garden pea, round seed shape (RR) was dominant over wrinkled seeds (rr), yellow cotyledon (YY) was dominant over green cotyledon (yy). What are the expected phenotypes in the $F_2$ generation of the cross $RRYY\times rryy$?

1. Only round seeds with green cotyledons
2. Only wrinkled seeds with green cotyledons
3. Round seeds with yellow cotyledons, and wrinkled seeds with yellow cotyledons
4. Only wrinkled seeds with yellow cotyledons

Q.

The height is under polygenic inheritance the plant having a genotype aabb has 20 cm height plant having genotype AaBbis 50 .cm what is the height of the plant having genotype AaBB

45

65

60

15

Q. Which of the following statement(s) is /are correct regarding the Mendelian dihybrid cross?
A. The F2 phenotypic ratio is 9 : 3 : 3 : 1
B. Law of independent assortment can be explained on the basis of the dihybrid cross
C. F2 generation is obtained through the cross between F1 plants with one of the two parental plants
D. The gametes produced by F1 plants are of 4 types in 1:1:1:1 ratio.

1. A, C, D
2. A, B, C, D
3. B, C, D
4. A, B, D

Q. In an experiment, individuals homozygous for 'ab' genes were crossed with wild type (++). The F${}_1$ hybrid thus produced was test crossed and progenies were produced in the following ratio:
++/ab 896
ab/ab 880
+a/ab 108
+b/ab 116

Calculate the distance between a and b genes.

1. 11.2 m.u.
2. 22.4 m.u.
3. 2.8 m.u.
4. 4.6 m.u.

Q. Which among the following are correct statements regarding the F${}_2$ generation obtained in Mendelian dihybrid cross?
(a) Phenotypic ratio 9 : 3 : 3 : 1
(b) Genotypic ratio 4: 2: 2: 1: 2: 1: 2: 1: 1
(c) $\frac{1}{4}$ plants are completely heterozygous.
(d) $F_2$ generation is obtained through selfing of $F_1$ plants.

1. a, c, d
2. a, b, c, d
3. a, b, c
4. b, c, d

Q.

Define and design a test − cross?

Q.

Mendel was successful in formulating the laws of inheritance whereas his predecessor were not because:

1. He studied one clear-cut character at a time

2. The characters studied by him were present on separate chromosomes

3. Of the right choice of material

4. He kept accurate records of this experiments

Q. In cross BbHh x BbHh, what fraction of offsprings will be heterozygous for both the traits?

1. 1/16
2. 1/2
3. 1/4
4. 1/8

Q. (a) What is polygenic inheritance ? Explain with the help of a suitable example.

(b) How are pleiotropy and Mendelian pattern of inheritance different from polygenic pattern of inheritance ? [5]

Q.

The contrasting pairs of factors in Mendelian crosses are called:

1. Allelomorphs

2. Multiple alleles

3. Paramorphs

4. Alloloci

Q. Define linkage and recombination.

Q. A dwarf Pea plant is treated with gibberellin which makes it tall. This plant is crossed with genetically pure tall plant. Phenotypic ratio in next generation shall be

1. 3 tall : 1 dwarf
2. all tall
3. all dwarf
4. $50\%tall:50\%dwarf$

Q.

Why do linked genes not follow the pattern of inheritance?

Q. In a dihybrid Mendelian cross, garden pea plants heterozygous for yellow flowers and round seeds are crossed with homozygous white flowers and wrinkled seeds. The genotypic and phenotypic ratio of F1 progeny would be :

1. 3 : 1
2. 1 : 1 : 1 : 1
3. 1 : 2 : 2 : 1
4. 9 : 3 : 3 : 1

Q.

What is Translocation?

Q. What is the exception to Mendels law of independent assortment ?

Q. In Mendel’s experiments with garden pea, round seed shape (RR) was dominant over wrinkled seeds (rr), yellow cotyledon (YY) was dominant over green cotyledon (yy). What are the expected phenotypes in the F2 generation of the cross $RRYY\times rryy$?

1. Only wrinkled seeds with green cotyledons.
2. Only wrinkled seeds with both yellow cotyledons.
3. Only round seeds with yellow cotyledons.
4. Round seeds with yellow cotyledons and wrinkled seeds with green cotyledons, round seeds with green cotyledons and wrinkled seeds with green cotyledons.

Q. In a monohybrid cross, what will be the total number of possible genotypes in F${}_2$ generation?

1. 9
2. 2
3. 3
4. 1

Q. Given below is a schematic diagram showing Mendels experiment on sweet pea plants with yellow round seeds (YYRR) and green wrinkled seeds (yyrr). Answer the questions that follows


(iii) Name the phenotypes produced in \(F_2\) progeny by self-pollination of \(F_1\) progeny.

Q. In multiple allele system an individual possess how many allelesaand a gamete posses how many alleles?

Q. Given below is a schematic diagram showing Mendels experiment on sweet pea plants with yellow round seeds (YYRR) and green wrinkled seeds (yyrr). Answer the questions that follows



(ii) Give the phenotype of \(F_1\) progeny.

Q.

Chromosomes arrange at the equatorial plate in which stage?

1. Prophase

2. Metaphase

3. Anaphase

4. Telophase

Q.

In a dihybrid cross AABB $\times$ aabb, $F_2$ progency of AABB, AABb, AaBB and AaBb accurs in ratio of________

1. 1: 1 : 1 : 1

2. 9 : 3 : 3 : 1

3. 1 : 2 : 2 : 1

4. 1 : 2 : 2 : 4

Q. The probability of having a child with blood group O to parents with blood groups A and B is

1. 4 out of 4
2. 3 out of 4
3. 2 out of 4
4. 1 out of 4

Q.

A tall violet flowered plant (TTVV) is crossed with a dwarf white flowered plant (ttvv). When the F₁ plants are self pollinated, a total of 1600, F₂ plants are produced. In the same experiment how many $F_2$ plants show $F_1$ phenotype?

1. 900

2. 100

3. 600

4. 300

Q.

How do you find the distance between two genes?

Q.

In which stage do the centromeres split in the meiosis?

Q.

The punnett square shown below represents the pattern of inhiritance in dihybrid cross when yellow (Y) is dominant over while (y) and Round (R) is dominant over wrinkled (r) seeds:

A plant of type 'H' will produce seeds with genotype identical to seeds produced by the plants of ?

1. Type J

2. Type M

3. Type N

4. Type P