Match List-I with List-II.
| List-I (Disorder) | List-II (Feature) |
| A. Sickle-cell anaemia | I. Development of breasts |
| B. Phenylketonuria | II. Inborn error of metabolism |
| C. Gynaecomastia | III. Incorrectly functioning globin |
| D. Colour blindness | IV. Sex-linked recessive disorder |
Choose the correct answer from the options given below:
Answer & explanation
Correct answer: option 3
The correct answer is Option (3) → A-III, B-II, C-I, D-IV
(A) Sickle-cell anaemia — this matches (III) Incorrectly functioning globin. Glutamic acid is replaced by valine at the sixth position of the β-globin chain. The globin made is abnormal in kind, a qualitative problem.
(B) Phenylketonuria — this matches (II) Inborn error of metabolism. The patient lacks the enzyme that changes phenylalanine into tyrosine, so phenylalanine builds up and harms the brain.
(C) Gynaecomastia — this matches (I) Development of breasts. It is seen in Klinefelter's syndrome (47, XXY), where a person with a male body build also develops breasts.
(D) Colour blindness — this matches (IV) Sex-linked recessive disorder. The genes for red-green colour blindness are on the X chromosome, so it is far more common in males.
NCERT Extract:
Mendelian Disorders – “… Colour Blidness : It is a sex-linked recessive disorder due to defect in either red or green cone of eye resulting in failure to discriminate between red and green colour.”
Mendelian Disorders – “… Phenylketonuria : This inborn error of metabolism is also inherited as the autosomal recessive trait. … Thalassemia differs from sickle-cell anaemia in that the former is a quantitative problem of synthesising too few globin molecules while the latter is a qualitative problem of synthesising an incorrectly functioning globin.”
Chromosomal Disorders – “… Such an individual has overall masculine development, however, the feminine development (development of breast, i.e., Gynaecomastia) is also expressed (Figure 4.17 a).”