Mendel's Dihybrid Experiments

Q.

Question 1
How do Mendel’s experiments show that traits may be dominant or recessive?

Q. In a homozygous plant, round seeds (R) are dominant over wrinkled seeds (r): [5 MARKS]
(a) Draw a Punnett square to show the gametes and offspring when both the plants have heterozygous round seeds (Rr).
(b) Mention the Phenotype and Genotype ratios of the offsprings in F2 generation.
(c) Name the sex chromosomes in human males and females.
(d) Briefly explain the term 'Mutation'.
(e) What is the number of chromosomes in the gametes of human beings?

Q. Given below is a schematic diagram showing Mendel's Experiment on sweet pea plants having axial flowers with round seeds (AARR) and terminal flowers with wrinkled seeds(aarr). Study the same and answer the questions that follow: [5 MARKS]



(a) Give the phenotype of F1 progeny.
(b) Give the phenotypes of F2 progeny produced by the self-pollination of F1 progeny.
(c) Give the phenotypic ratio of F2 progeny.
(d) Name and explain the law induced by Mendel on the basis of the above observation.

Q.

Mendel formulated the law of purity of gametes on the basis of

1. Dihybrid cross

2. Monohybrid cross

3. Back cross

4. Test cross

Q.

Question 11
Two pea plants one with round green seeds (RRyy) and another with wrinkled yellow (rrYY) seeds produce F1 progeny that have round, yellow (RrYy) seeds. When F1 plants are selfed, the F2 progeny will have a new combination of characters. Choose the new combination of the following.
(i) Round, yellow
(ii) Round, green
(iii) Wrinkled, yellow
(iv)Wrinkled, green
(a) (i) and (ii)
(b) (i) and (iv)
(c) (ii) and (iii)
(d) (i) and (iii)

Q.

In Mendel’s monohybrid cross of tall vs dwarf plants, the $F_1$ progeny are ___.

1. Homozygous

2. Heterozygous

3. Hemizygous

4. Either a or b

Q.

What is a dihybrid cross ?

Q.

A dihybrid tall plant with yellow flowers (TtYy) was crossed with a dwarf plant bearing white flowers (ttyy). What percentage of progeny is expected to be homozygous tall bearing yellow flowers?

1. 0%

2. 75%

3. 25%

4. 50%

Q.

Validity of Mendels law of segregation is established only when

1. One parent is crossed with F1 hybrid

2. Two pure breeding contrasting characters are crossed

3. Two F1 hybrids are crossed

4. None of the above

Q. During a dihybrid cross with contrasting characters in $F_2$ generation parental genotypes will appear in ______ ratio.

1. 1/16
2. 2/16
3. 3/16
4. 9/16.

Q. In the $F_2$ 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.

Q. In the dihybrid cross, the two parental genotypes are AABB and aabb. The genotype of all F${}_1$ plants is AaBb. What phenotype ratio will be observed in the F${}_2$ generation?

1. 8:4:2:1
2. 1:1:1:1
3. 4:2:2:1
4. 1:2:2:1
5. 9:3:3:1

Q. In a plant, red fruit (R) is dominant over yellow fruit (r) and tallness (T) is dominant over shortness (t). If a plant with RRTt genotype is crossed with a plant that is rrtt,

1. 75% will be tall with red fruit.
2. 25% will be tall with red fruit.
3. All the offspring will be tall with red fruit.
4. 50% will be tall with red fruit.

Q. More than One Answer Type
एक से अधिक उत्तर प्रकार के प्रश्न

Which of the following statements is/are true for the offsprings produced in F₁ generation from the cross between two pea plants with the genotypes XxYY and XXYy?

जीनप्ररूप (जीनोटाइप) XxYY तथा XXYy वाले दो मटर के पादपों के बीच होने वाले संकरण से F₁ पीढ़ी में उत्पन्न संतति के लिए निम्नलिखित में से कौनसा/कौनसे कथन सही है/हैं?

1. 25% of the offsprings are double heterozygotes
   
   25% संतति द्वि-विषमयुग्मजी होते हैं
2. 50% of the offsprings have the genotype XxYY
   
   50% संतति में जीनप्ररूप (जीनोटाइप) XxYY होता है
3. No offspring with the genotype xxyy is produced
   
   जीनप्ररूप (जीनोटाइप) xxyy वाला संतति उत्पन्न नहीं होता है
4. 50% of the offsprings have the genotype XXYY
   
   50% संतति में जीनप्ररूप (जीनोटाइप) XXYY होता है

Q.

In the above cross, what is the allelic composition of the female gamete?

1. (aB)

2. (Ab)

3. (ab)

4. (AB)

Q. Consider the cross $AaBbCcDdEe\times aaBbccddee$. What proportion of the progeny will genotypically resemble the first parent?

1. $1/64$
2. $2/64$
3. $4/16$
4. $4/46$

Q.

Statement 1: Monozygotic twins are genetically distinct.
Statement 2: Dizygotic twins are formed when two eggs are fertilised by a single sperm.​

1. Statement 1- True, Statement 2- True​
2. Statement 1- True, Statement 2- False​
3. Statement 1- False, Statement 2- False​
4. Statement 1- False, Statement 2- True​

Q.

The centromere is a part of

1. Chromosome

2. Endoplasmic reticulum

3. Ribosomes

4. Mitochondria

Q.

How many different phenotypes and genotypes are obtained in the $F_2$ generation of Mendel’s dihybrid cross?

1. 4 phenotypes and 9 genotypes

2. 4 phenotypes and 16 genotypes

3. 16 phenotypes and 8 genotypes

4. 2 phenotypes and 16 genotypes

Q.

The phenotypic ratio for Mendel’s dihybrid cross is

1. 3:1

2. 1:2:1

3. 9:3:3:1

4. 1:1

Q.

with the help of pinnet square/checker board show the dihybrid cross taking two pairs of characters.

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. A cross between pure tall Pea plant with green pods and dwarf Pea plant with yellow pods will produce tall $F_2$ plants, out of 16

1. 13
2. 12
3. 15
4. 7

Q. Arrange the following in decreasing order based on the results obtained in the $F_2$ progeny of a dihybrid cross.
(A) Total number of parental genotypes
(B) Total number of recombinant genotypes
(C) Total phenotypes
(D) Total genotypes

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

Q.

The gametes produced by Mendel’s $F_1$ dihybrid are

1. (YR) and (Yr)

2. (YR), (Yr), (YR) and (yr)

3. (YR) and (yR)

4. (yR) and (Yr)

Q. In a dihybrid cross between RRYY and rryy parents, the number of RrYy genotypes possible in F${}_2$ generation will be

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

Q.

The ratio 9:3:3:1 represents:

1. Mendel’s dihybrid phenotypic ratio

2. Mendel’s monohybrid genotypic ratio

3. Mendel’s monohybrid phenotypic ratio

4. Mendel’s dihybrid genotypic ratio

Q.

A cross between pure-bred pea plants having yellow round seeds with those having green wrinkled seeds would produce ${\text{F}}_1$ plants with:

1. Round green seeds

2. Wrinkled green seeds

3. Wrinkled yellow seeds

4. Round yellow seeds

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 P

2. Type N

3. Type M

4. Type J

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