| 1. | It is an inborn error of metabolism. |
| 2. | It is inherited as an autosomal recessive trait. |
| 3. | The affected individual lacks an enzyme that converts the amino acid tyrosine into phenylalanine. |
| 4. | Accumulation of phenylpyruvic acid in brain results in mental retardation. |
| Statement I: | Thalassemia is a qualitative problem of synthesising an incorrectly functioning globin. |
| Statement II: | Sickle cell anaemia is a quantitative problem of synthesising too few globin molecules. |
| I: | is an aneuploidy |
| II: | causes infertility in affected females |
| III: | does not affect the development of secondary sexual characters in affected females |
| Mother | Father | Daughter | Son | |
| 1. | Rr | Rr | rr | rr |
| 2. | Rr | Rr | rr | RR |
| 3. | rr | Rr | RR | rr |
| 4. | RR | rr | Rr | Rr |