Frank solutions for Biology Part 2 [English] Class 10 ICSE chapter 3 - Principles of Genetics [Latest edition]

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Mendel conducted his hybridization experiments on _______

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If a homozygous tall plant is crossed with a heterozygous tall plant, the proportion of tall progeny would be ____________

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Mendel used ______ pairs of a characters for his experiments.

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Father of genetics ________

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The allele which masks the effect of its complement is _______

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If any of Mendel's characters were linked; one would have been unable to derive.

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The contrasting characters used by Mendel are called _____

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If a pea plant with round seeds is selfed and the offspring are in the ratio 3:1, then the plant is _________

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A cross where two pairs of alleles are considered is a ____________

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Human sex chromosomes are __________

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Haemophilia is due to recessive gene on __________

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Males have more chances of suffering from sex-linked disease because of ___________

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A single recessive trait, able to express must be on _________

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A carrier haemophilic woman marries a haemophilic man. What are the chances for her progeny to be haemophilic?

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 A colour blind woman marries a normal man, in the progeny _________

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A man can transfer his sex-linked gene to his ______________

The recessive gene is one that expresses itself in ______.

The sex chromosome in a human ovum is ______.

A zygote which has Y chromosome inherited from the father will develop into a ______.

Four friends P, Q, R and S were discussing the examples of genetic disorders. The examples they quoted were as follows:

P. Colour blindness and Malaria

Q. Albinism and Cholera

R. Haemophilia and Colour blindness

S. Haemophilia and Albinism

Who gave the correct examples?

Assertion (A): Genes present in every cell of an organism control the traits of the organisms.

Reason (R): Gene is specific segment of DNA occupying specific position on a chromosome.

Assertion (A): In grasshoppers, females are heterogametic and males are homogametic.

Reason (R): In grasshoppers, male has only one sex chromosome (XO) whereas the female has sex chromosomes (XX).

Assertion (A): Round green seeds in pea can be represented by RRyy of Rryy.

Reason (R): Round yellow seeds and green wrinkled seeds are parental combinations whereas round green and wrinkled yellow are recombinants.

Assertion (A): If a mother has two dominant alleles for black hair and father has two recessive alleles for blonde hair then their child will inherit one dominant allele from mother and one recessive allele from father and will have black hair.

Reason (R): Progeny inherits one genes for each trait from its parents but the trait shown by progeny depends on inherited alleles.

Name the following.

Father of genetics.

Name the following.

The branch of Science that deals with heredity.

Name the following:

A genetic disorder in which the blood does not clot.

Name the following:

The basic units of heredity.

Name the following.

The sex chromosome of male.

Name the following.

The number of pairs of autosomes in human being.

Name the following.

The chemical substance constituting genes.

Name the following.

An alternation in the genetic material that can be inherited.

State whether the following is true or false. If false, rewrite the correct form of the statement by changing the word/words.

The plant used by Mendel was sweet pea.

State whether the following is true or false. If false, rewrite the correct form of the statement by changing the word/words.

The chemical present in RNA is gene.

State whether the following is true or false. If false, rewrite the correct form of the statement by changing the word/words.

Mendel used 5 pair of characteristics for his experiment.

State whether the following is true or false. If false, rewrite the correct form of the statement by changing the word/words.

A cross where the pairs of alleles are crossed is a dihybrid cross.

Differentiate between genotype and phenotype.

Differentiate between the following:

Dominant and Recessive genes

Differentiate between the following:

Homogametic and Heterogametic

Differentiate between the following:

Monohybrid and Polyhybrid cross

Define the following:

Genotype

Define the following:

Phenotype

Define the following:

Homozygous

Define the following:

Heterozygous

Define the following:

Allele

Define the following:

Dominant

Define the following:

Recessive

______ is the scientific name of garden pea, which Mendel used for his experiments.

Explain the following.

Why colour blindness is more common in men than in women.

Why did Mendel select pea plants for his experiment?

Explain the following.

How the sex of a child depends upon its father.

Predict the genotype and phenotype of the following cross in pea.

TT × Tt

(Capital letters show dominance)

1. Give the ratio of phenotypes of the cross.
2. Mention whether the cross is a monohybrid or dihybrid.

Predict the genotype and phenotype of the following cross in pea.

tt × TT

(Capital letters show dominance)

1. Give the ratio of phenotypes of the cross.
2. Mention whether the cross is a monohybrid or dihybrid.

Predict the genotype and phenotype of the following cross in pea.

TTrr × ttRR

(Capital letters show dominance)

1. Give the ratio of phenotypes of the cross.
2. Mention whether the cross is a monohybrid or dihybrid.

Predict the genotype and phenotype of the following cross in pea.

TtRr × TtRr

(Capital letters show dominance)

1. Give the ratio of phenotypes of the cross.
2. Mention whether the cross is a monohybrid or dihybrid.

Define the following:
Sex chromosomes

Define the following:
Sex-linked characters

State Mendel’s laws.

Name two genetic disorders commonly seen in human body.

A woman has normal vision but her father was colour blind. If she is married to a colour blind person, report on the occurrence of the disease in the progeny.

State Mendel's law of dominance.

State Mendel’s Law of Segregation.

Suppose you are given two pairs of contrasting characters: Seed colour → yellow and green , seed coat → round and wrinkled.

Fill in the following table to show that F₂ generation according to the principle of independant assortment as given by Mendel.

Answer the following briefly:

Explain with the help of a chart what will be the colour of a child's hair if father has got dominant gene for black hair and mother has recessive gene for brown hair?

Explain the following terms:

Laws of Inheritance

Explain the following term:

Sex-linked characters

A family consists of two parents and their five children and the pedigree chart below shows the inheritance of the trait colour blindness . 

(i) Who is colour blind in parents - Father or Mother?
(ii) How many daughters and sons have beeen born in the family?
(iii) What does the child 1 indicate about this trait?
(iv) Complete the depiction of all probabilities of the trait among the children 2-5 in the chart.
(v) On which chromosome is the gene of this trait located?
(vi) Name one other trait in humans which follows the similar mode of inheritance.

A homozygous plant having round (R) and yellow (Y) seeds is crossed with homozygous plant having wrinkled (r) and green (y) seeds:

1. Give the scientific name of the plant on which Mendel conducted his hybridization experiments.
2. Give the genotype of the F₁ generation.
3. Give the dihybrid phenotypic ratio and the phenotype of the offspring of the F₂ generation when two plants of the F₁ generation are crossed.
4. Name and state the law which explains the dihybrid ratio.
5. Give the possible combinations of gametes that can be obtained from F₁ hybrid.

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 :

(i) Give the phenotype of F₁ progeny.
(ii) Give the phenotypes of F₂ progeny produced upon by the self-pollination of F₁ progeny.
(iii) Give the phenotypic ratio of F₂ progeny.
(iv) Name and explain the law induced by Mendel on the basis of the above observation.

In a homozygous plant round seeds (R) are dominant over wrinkled seeds (r):

1. Draw a Punnett square to show the gametes and offsprings when both the plants have heterozygous round seeds (Rr).
2. Mention the phenotype and genotype ratios of the offsprings in F₂ generation.
3. Name the sex chromosomes in human males and females.
4. Briefly explain the term ‘Mutation’.
5. What is the number of chromosomes in the gametes of human beings?

A homozygous tall plant (T) bearing red-coloured (R) flowers is crossed with a homozygous dwarf (t) plant bearing white (r) flowers:

1. Give the genotype and phenotype of the plants of F₁ generation.
2. Mention the possible combinations of the gametes that can be obtained from the F₁ hybrid plant.
3. State Mendel’s law of independent assortment.
4. Mention the phenotypes of the offsprings obtained in F₂ generation.
5. What is the phenotypic ratio obtained in F₂ generation?

In a homozygous pea plant, axial flowers (A) are dominant over terminal flowers (a).

1. What is the phenotype and genotype of the F₁ generation if a plant bearing pure axial flowers is crossed with a plant bearing pure terminal flowers?
2. Draw a Punnett square board to show the gametes and offsprings when both the parent plants are heterozygous for axial flowers.
3. What is the phenotypic ratio and genotypic ratio of the above cross shown in (b)?
4. Name two genetic disorders commonly seen in human males.

State Mendel's law of dominance.

1. A pure tall plant (TT) is crossed with a pure dwarf plant (tt). Draw Punnett squares to show
   1. F₁, generation
   2. F₂ generation.
2. Give the phenotype of F₂ generation.
3. Give the phenotype and genotypic ratios of the F₁ and F₂ generations.

Name any one X-linked disease found in humans.

A pea plant which is homozygous for green pods which are inflated (GGII) is crossed with a homozygous plant for yellow pod which are constricted (ggii).

Answer the following questions:

1. Give the phenotype and genotype of the F₁ generation.
2. Write the phenotypic ratio of the F₂ generation.
3. Write the possible combinations of the gametes that can be obtained if two F₁ hybrid plants are crossed.
4. State Mendel’s law of segregation of gametes.
5. What is the scientific name of the plant which Mendel used for his experiments on inheritance?

A homozygous dominant tall pea plant bearing red flowers (TTRR) is crossed with a homozygous recessive dwarf pea plant bearing white flowers (ttrr).

1. What is the phenotype and genotype of F₁ individuals?
2. Write the possible combination of gametes that are obtained when two F₁ hybrid plants are crossed.
3. Mention the phenotypic ratio of the F₂ generation.
4. State Mendel’s Law of Independent Assortment.
5. Name two X-linked disorders found in humans.

In Mendel’s experiments, tall pea plants (T) are dominant over dwarf pea plants (t).

1. What is the phenotype and genotype of the F₁ generation if a homozygous tall plant is crossed with a homozygous dwarf plant?
2. Draw a Punnett square board to show the gametes and offspring when both the parents are heterozygous for tallness.
3. What is the phenotypic ratio and genotypic ratio of the above cross in (b)?
4. State Mendel’s Law of Dominance.
5. What is a Dihybrid Cross?

Given below is a schematic representation of the inheritance of the shape of the seeds of garden peas. Answer the questions that follow:

1. Which is the dominant and recessive allele of the trait?
2. What does the ratio 3 : 1 in the F₂ generation represent?
3. State Mendel's Law of Dominance.

A pure breeding red flower variety of pea plant (RR) is crossed with a pure breeding white flower variety of pea plant (rr). Draw a Punnett square to find out the Phenotypic and Genotypic ratios of the progeny belonging to the F₂ generation.

Explain the term Alleles.

Explain the term ‘Phenotype’?