CBSE Class 12 Biology Principles Of Inheritance And Variation Worksheet Set D

CBSE Class 12 Biology Principles of Inheritance and Variation (3). CBSE issues sample papers every year for students for class 12 board exams. Students should solve the CBSE issued sample papers to understand the pattern of the question paper which will come in class 12 board exams this year. The sample papers have been provided with marking scheme. It’s always recommended to practice as many CBSE sample papers as possible before the board examinations. Sample papers should be always practiced in examination condition at home or school and the student should show the answers to teachers for checking or compare with the answers provided. Students can download the sample papers in pdf format free and score better marks in examinations. Refer to other links too for latest sample papers.

 QUESTIONS 

1.Name one autosomal dominant and one autosomal recessive

2..Name one autosomal dominant and one autosomal recessive Mendelian disorder in humans.

3.Write the genotype of

i) an individual who is carrier of sickle cell anaemia gene but apparently unaffected, and

ii) an individual affected with the disease.

4.Write the percentage of F2 homozygous and heterozygous populations in a typical monohybrid cross.

5.A man with blood group A married a woman with B group. They have a son with AB blood group and a daughter with blood group O. Workout the cross and show the possibility of such inheritance.

Important Questions for NCERT Class 12 Biology Principles of Inheritance and Variation

Ques. Which one of the following conditions in humans is correctly matched with its chromosomal abnormality/linkage?
(a) Erythroblastosis fetalis - X-linked
(b) Down’s syndrome - 44 autosomes + XO
(c) Klinefelter’s syndrome - 44 autosomes + XXY
(d) Colour blindness - Y-linked 

Answer: C

Ques. Both sickle cell anaemia and Huntington’s chorea are
(a) virus-related diseases
(b) bacteria-related diseases
(c) congenital disorders
(d) pollutant-induced disorders. 

Answer: C

Ques. If a colour blind woman marries a normal visioned man, their sons will be
(a) all colour blind
(b) all normal visioned
(c) one-half colour blind and one-half normal
(d) three-fourths colour blind and one-fourth normal. 

Answer: A

Ques. Cri-du-chat syndrome in humans is caused by the
(a) trisomy of 21st chromosome
(b) fertilisation of an XX egg by a normal Y-bearing sperm
(c) loss of half of the short arm of chromosome 5
(d) loss of half of the long arm of chromosome 5.

Answer: C

Ques. Sickle cell anaemia has not been eliminated from the African population because
(a) it is controlled by dominant genes
(b) it is controlled by recessive genes
(c) it is not a fatal disease
(d) it provides immunity against malaria. 

Answer: D

Ques. A man and a woman, who do not show any apparent signs of a certain inherited disease, have seven children (2 daughters and 5 sons). Three of the sons suffer from the given disease but none of the daughters affected. Which of the following mode of inheritance do you suggest for this disease?
(a) Sex-linked dominant
(b) Sex-linked recessive
(c) Sex-limited recessive
(d) Autosomal dominant 

Answer: B

Ques. A woman with 47 chromosomes due to three copies of chromosome 21 is characterised by
(a) superfemaleness (b) triploidy
(c) Turner’s syndrome (d) Down’s syndrome.

Answer: D

Ques. Haemophilia is more commonly seen in human males than in human females because
(a) a greater proportion of girls die in infancy
(b) this disease is due to a Y-linked recessive mutation
(c) this disease is due to an X-linked recessive mutation
(d) this disease is due to an X-linked dominant mutation. 

Answer: C

Ques. Which of the following is not a hereditary disease?
(a) Cystic fibrosis (b) Thalassaemia
(c) Haemophilia (d) Cretinism 

Answer: D

Ques. A woman with normal vision, but whose father was colour blind, marries a colour blind man. Suppose that the fourth child of this couple was a boy. This boy
(a) may be colour blind or may be of normal vision
(b) must be colour blind
(c) must have normal colour vision
(d) will be partially colour blind since he is heterozygous for the colour blind mutant allele.

Answer: A

Ques. A male human is heterozygous for autosomal genes A and B and is also hemizygous for haemophilic gene h. What proportion of his sperms will be abh?
(a) 1/8 (b) 1/32
(c) 1/16 (d) 1/4 

Answer: A

Ques. A normal woman, whose father was colour-blind is married to a normal man. The sons would be
(a) 75% colour-blind (b) 50% colour-blind
(c) all normal (d) all colour-blind.

Answer: B

Ques. The recessive genes located on X-chromosome humans are always
(a) lethal (b) sub-lethal
(c) expressed in males (d) expressed in females.

Answer: C

Ques. Pattern baldness, moustaches and beard in human males are examples of
(a) sex linked traits
(b) sex limited traits
(c) sex influenced traits
(d) sex determining traits. 

Answer: C

Ques. Which one of the following conditions though harmful in itself, is also potential saviour from a mosquito borne infectious disease ?
(a) Thalassaemia
(b) Sickle cell anaemia
(c) Pernicious anaemia
(d) Leukaemia 

Answer: B

Ques. Down’s syndrome is caused by an extra copy of chromosome number 21. What percentage of offspring produced by an affected mother and a normal father would be affected by this disorder?
(a) 100 % (b) 75 %
(c) 50 % (d) 25 % 

Answer: C

160. Christmas disease is another name for
(a) haemophilia B (b) hepatitis B
(c) Down’s syndrome (d) sleeping sickness.

Answer: A

Ques. A diseased man marries a normal woman. They get three daughters and five sons. All the daughters were diseased and sons were normal. The gene of this disease is
(a) sex linked dominant (b) sex linked recessive
(c) sex limited character (d) autosomal dominant.

Answer: A

Ques. Which of the following is a correct match?
(a) Down’s syndrome - 21st chromosome
(b) Sickle cell anaemia - X-chromosome
(c) Haemophilia - Y-chromosome
(d) Parkinson’s disease - X and Y chromosome

Answer: A

Ques. Sickle cell anaemia induce to
(a) change of amino acid in a-chain of haemoglobin
(b) change of amino acid in b-chain of haemoglobin
(c) change of amino acid in both a and b chains of haemoglobin
(d) change of amino acid either a or b chains of haemoglobin. 

Answer: B

Ques. Mongolian Idiocy due to trisomy in 21st chromsome is called
(a) Down’s syndrome
(b) Turner’s syndrome
(c) Klinefelter’s syndrome
(d) Triple X syndrome. 

Answer: A

Ques. In Drosophila, the XXY condition leads to femaleness whereas in human beings the same condition leads to Klinefelter’s syndrome in male. It proves
(a) in human beings Y chromosome is active in sex determination
(b) Y chromosome is active in sex determination in both human beings and Drosophila
(c) in Drosophila Y chromosome decides femaleness
(d) Y chromosome of man have genes for syndrome.

Answer: A

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