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Principles of Inheritance and Variation · Question 39

NEET (UG) 2022 (Phase 2)MCQEasy📈 Topic in 50% papers+4−1
1

If a female individual is with small round head, furrowed tongue, partially open mouth and broad palm with characteristic palm crease. Also the physical, psychomotor and mental development is retarded. The karyotype analysis of such an individual will show :

  1. Trisomy of chromosome 21
  2. 47 chromosomes with XXY sex chromosomes
  3. 45 chromosomes with XO sex chromosomes
  4. 47 chromosomes with XYY sex chromosomes

Answer

(1) Trisomy of chromosome 21

Solution

As per NCERT, Down's syndrome is caused by the presence of an additional copy of chromosome number 21 (trisomy of 21).

The affected individual is short statured with small round head, furrowed tongue and partially open mouth; the palm is broad with characteristic palm crease; physical, psychomotor and mental development is retarded.

XXY is Klinefelter's syndrome (male) and XO is Turner's syndrome, which do not show these features.

∴ The karyotype shows trisomy of chromosome 21.

Answer: (1)

NEET (UG) 2022 (Phase 2)

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2

Select the incorrect match regarding the symbols used in the Pedigree analysis:

  1. [figure] – Parent with male child affected with disease
  2. [figure] – Sex unspecified
  3. [figure] – Affected individual
  4. [figure] – Consanguineous mating
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3

A normal girl, whose mother is haemophilic marries a male with no ancestral history of haemophilia. What will be the possible phenotypes of the offspring? Choose the most appropriate answer from the options given below:

  1. B and D only
  2. A and B only
  3. B and C only
  4. A and D only
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4

The production of gametes by the parents, formation of zygotes, the F1 and F2 plants, can be understood from a diagram called :

  1. Net square
  2. Bullet square
  3. Punch square
  4. Punnett square
NEET (UG) 2021
5

In a cross between a male and female, both heterozygous for sickle cell anaemia gene, what percentage of the progeny will be diseased?

  1. 100%
  2. 50%
  3. 75%
  4. 25%
NEET (UG) 2021
6

Experimental verification of the chromosomal theory of inheritance was done by

  1. Sutton
  2. Mendel
  3. Morgan
  4. Boveri
NEET (UG) 2020
7

Select the correct match

  1. Thalassemia – X linked
  2. Sickle cell anaemia – Autosomal recessive trait, chromosome-11
  3. Phenylketonuria – Autosomal dominant trait
  4. Haemophilia – Y linked
NEET (UG) 2020
8

Identify the wrong statement with reference to the gene ‘I’ that controls ABO blood groups.

  1. Allele ‘i’ does not produce any sugar.
  2. The gene (I) has three alleles.
  3. When IA and IB are present together, they express same type of sugar.
  4. A person will have only two of the three alleles.
NEET (UG) 2020
9

How many true breeding pea plant varieties did Mendel select as pairs, which were similar except in one character with contrasting traits?

  1. 14
  2. 4
  3. 2
  4. 8
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10

The frequency of recombination between gene pairs on the same chromosome as a measure of the distance between genes was explained by :

  1. Alfred Sturtevant
  2. Gregor J. Mendel
  3. Sutton Boveri
  4. T.H. Morgan
NEET (UG) 2019
11

In Antirrhinum (Snapdragon), a red flower was crossed with a white flower and in F1 generation, pink flowers were obtained. When pink flowers were selfed, the F2 generation showed white, red and pink flowers. Choose the incorrect statement from the following :

  1. Ratio of F2 is 14 (Red) : 24 (Pink) : 14 (White)
  2. Law of Segregation does not apply in this experiment
  3. This experiment does not follow the Principle of Dominance
  4. Pink colour in F1 is due to incomplete dominance
NEET (UG) 2019

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