Biology · Textbook solutions

Inheritance and Variation

Every solved example, exercise, and miscellaneous question, in the order the textbook teaches them. Plus every board question asked from this chapter. · 36 questions

Exercise

36 q

Q1. Multiple choice questions

Practice · 8

Multiple choice questions.
Ex Q1(1) $\text{F}_2$
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Ex Q1(2) $\text{F}_2$
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Ex Q1(3) $A cross between an individual with unknown genotype for a trait with recessive plant for that trait is ..............$
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Ex Q1(4) $\text{F}_2$
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Ex Q1(5) $If the centromere is situated near the end of the chromosome, the chromosome is called ................$
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Ex Q1(6) $Chromosomal theory of inheritance was proposed by ................$
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Ex Q1(7) $If the genes are located in a chromosome as p-q-r-s-t, which of the following gene pairs will have least probability of being inherited together?$
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Ex Q1(9) $A colourblind man marries a woman, who is homozygous for normal colour vision ,the probability of their son being colourblind is -$
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Q2. Very Short Answer Questions

Practice · 9

Very Short Answer Questions.
Ex Q2(1) $Explain the statements : a. Test cross is a back cross but back cross is not necessarily a test cross. b. Law of dominance is not universal.$
Ex Q2(2) $Define the following terms : a. Dihybrid cross b. Homozygous c. Heterozygous d. Test cross$
Ex Q2(3) $What is allosome?$
Ex Q2(4) $What is crossing over?$
Ex Q2(5) $Give one example of autosomal recessive disorder.$
Ex Q2(6) $What are X-linked genes?$
Ex Q2(7) $What are holandric traits?$
Ex Q2(8) $Give an example of chromosomal disorder caused due to non-disjunction of autosomes.$
Ex Q2(9) $Give one example of complete sex linkage?$

Q3. Short Answer Questions

Practice · 10

Short Answer Questions.
Ex Q3(1) $Enlist seven traits of pea plant selected/ studied by Mendel.$
Ex Q3(2) $Why law of segregation is also called the law of purity of gametes?$
Ex Q3(3) $Write a note on pleiotropy.$
Ex Q3(4) $What are the reasons of Mendel success?$
Ex Q3(5) $“In humans, father is responsible for determination of sex of child and not the mother”. Justify.$
Ex Q3(6) $What is linkage? How many linkage groups do occur in human being?$
Ex Q3(7) $Write note on -PKU$
Ex Q3(8) $Compare - X-chromosome and Y-chromosome.$
Ex Q3(9) $Explain the chromosomal theory of inheritance.$
Ex Q3(10) $Observe the given pedigree chart and answer the following questions. a. Identify whether the trait is sex linked or autosomal. b. Give an example of a trait in human beings which shows such a pattern of inheritance.$

Q4. Match the column-I with column-II and re-write the...

Practice · 1

Ex Q4 $Match the column-I with column-II and re-write the matching pairs. Column-I Column-II 1. 21 trisomy a. Turner’s syndrome 2. X-monosomy b. Klinefelter’s syndrome 3. Holandric traits c. Down's syndrome 4. Feminized male d. Hypertrichosis$

Column-I	Column-II
1. 21 trisomy	a. Turner’s syndrome
2. X-monosomy	b. Klinefelter’s syndrome
3. Holandric traits	c. Down's syndrome
4. Feminized male	d. Hypertrichosis

Q5. Long answer type questions

Practice · 8

Long answer type questions.
Ex Q5(1) $What is dihybrid cross? Explain it with the suitable example and checker board method.$
Ex Q5(2) $Explain with the suitable example an independent assotrment.$
Ex Q5(3) $Define test cross and explain its significance.$
Ex Q5(4) $What is parthenogenesis? Explain the haplo-diploid method of sex determination in Honey bee.$
Ex Q5(5) $In the answer for inheritance of X-linked genes, Madhav had shown carrier male. His answer was marked incorrect. Madhav was wondering why his marks were cut. Explain the reason.$
Ex Q5(6) $With the help of neat labelled diagram, describe the structure of chromosome.$
Ex Q5(7) $What is cris-cross inheritance? Explain with suitable example.$
Ex Q5(8) $Describe the different types of choromosomes.$

What the board has asked from this chapter

Questions per paper · 5 papers · 2024 to 2026

June 2026

2 q

Q. 14 $With the help of graphical representation explain sex determination in honey-bees.$
Sex Determination
Q. 30 $2n-2$
Sex Linked Inheritance

	A		B
(i)	Monosomy	(1)	_____
(ii)	_____	(2)	$2n-2$
(iii)	Trisomy	(3)	_____
(iv)	_____	(4)	$2n+2$

February 2026

3 q

Q. 2(iii) $Name the gene which is inherited directly from father to son.$
Sex Linked Inheritance
Q. 4 $Differentiate between complete sex-linkage and incomplete sex-linkage with reference to location of the gene and inheritance.$
Linkage and Crossing Over
Q. 16 $Explain criss-cross inheritance with reference to bleeder’s disease by suitable charts.$
Sex Linked Inheritance

July 2025

3 q

Q. 1(v) $The type of gene interaction deviating from Mendel's findings of 3 : 1 to 1 : 2 is_____.$
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Deviations from Mendel's Findings
Q. 10 $Enlist the types of chromosomes on the basis of position of centromere.$
Chromosomes
Q. 20 $21^{\text{st}}$
Genetic Disorders

July 2024

4 q

Q. 1(ii) $The synonymous term for centromere is _______.$
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Chromosomes
Q. 6 $21^{\text{st}}$
Genetic Disorders
Q. 15 $Suggest the specific term for the following : (a) Both male and female reproductive organs present in same organism. (b) Y- linked gene (c) Unfertilised egg develops into haploid male bee.$
Sex Determination

Q. 19

Select and fill in the boxes (i) to (vi) from given list of options. List of options — Sickle cell anaemia, Widow’s peak, Flower colour of Mirabilis, Human blood groups, Coat colour of cattle, Klinefelter’s syndrome. Genetic trait Example (a) Incomplete dominance (i) _____(b) Pleiotropy (ii) _____(c) Codominance (iii) _____(d) Multiple allelism (iv) _____(e) Sex chromosomal disorder (v) _____(f) Autosomal disorder (vi) _____

Genetic trait	Example
(a) Incomplete dominance	(i) _____
(b) Pleiotropy	(ii) _____
(c) Codominance	(iii) _____
(d) Multiple allelism	(iv) _____
(e) Sex chromosomal disorder	(v) _____
(f) Autosomal disorder	(vi) _____

Deviations from Mendel's Findings

March 2024

2 q

Q. 3 $What are the reasons for the success of Mendel?$
Chromosomes and Mechanism of Inheritance
Q. 28 $What are chromosomal disorders? Describe Turner’s syndrome and Klinefelter’s syndrome.$
Genetic Disorders

The 10 board questions to practise first

The questions the board asked again come first, most asked first. Each one says how often and when.

Question 1
Asked 2 times: Jul 2024, Jul 2025
Q. 20 $21^{\text{st}}$
Question 2
This type asked 2 times: Feb 2026, Jun 2026. This one: Jun 2026
Q. 30 $2n-2$
Question 3
Asked once: Feb 2026 (same type asked 2 times)
Q. 2(iii) $Name the gene which is inherited directly from father to son.$
Question 4
Asked once: Jun 2026
Q. 14 $With the help of graphical representation explain sex determination in honey-bees.$
Question 5
Asked once: Feb 2026
Q. 4 $Differentiate between complete sex-linkage and incomplete sex-linkage with reference to location of the gene and inheritance.$
Question 6
Asked once: Feb 2026
Q. 16 $Explain criss-cross inheritance with reference to bleeder’s disease by suitable charts.$
Question 7
Asked once: Jul 2025
Q. 1(v) $The type of gene interaction deviating from Mendel's findings of 3 : 1 to 1 : 2 is_____.$
Tap an option to check your answer.
Question 8
Asked once: Jul 2025
Q. 10 $Enlist the types of chromosomes on the basis of position of centromere.$
Question 9
Asked once: Jul 2024
Q. 1(ii) $The synonymous term for centromere is _______.$
Tap an option to check your answer.

	A		B
(i)	Monosomy	(1)	_____
(ii)	_____	(2)	$2n-2$
(iii)	Trisomy	(3)	_____
(iv)	_____	(4)	$2n+2$

Question 10

Asked once: Jul 2024

Q. 19

Select and fill in the boxes (i) to (vi) from given list of options. List of options — Sickle cell anaemia, Widow’s peak, Flower colour of Mirabilis, Human blood groups, Coat colour of cattle, Klinefelter’s syndrome. Genetic trait Example (a) Incomplete dominance (i) _____(b) Pleiotropy (ii) _____(c) Codominance (iii) _____(d) Multiple allelism (iv) _____(e) Sex chromosomal disorder (v) _____(f) Autosomal disorder (vi) _____

Exercise

Q1. Multiple choice questions

Q2. Very Short Answer Questions

Q3. Short Answer Questions

Q4. Match the column-I with column-II and re-write the...

Q5. Long answer type questions

What the board has asked from this chapter

June 2026

February 2026

July 2025

July 2024

March 2024

The 10 board questions to practise first

Question 1

Question 2

Question 3

Question 4

Question 5

Question 6

Question 7

Question 8

Question 9

Question 10