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Biology · 2025 · 2 marks
CBSE 2025 · Region 1 · Set 3 · Q18
Study the two different crosses given below: Identify the abnormalities '1' and '2' in the offsprings of given crosses and distinguish between them.
Study the two different crosses given below :
Identify the abnormalities '$\displaystyle 1$' and '$\displaystyle 2$' in the offsprings of given crosses and distinguish between them.
Identify the abnormalities '$\displaystyle 1$' and '$\displaystyle 2$' in the offsprings of given crosses and distinguish between them.Marking-scheme solution
$\displaystyle 1$ = Turner's Syndrome ($\displaystyle 44$ + XO)
$\displaystyle 2$ = Down's Syndrome ($\displaystyle 45$ + XY / $\displaystyle 45$ + XX)
| Turner's Syndrome | Down's syndrome / Trisomy |
| Absence of one of the X chromosome $\displaystyle 45$ with XO | Trisomy $\displaystyle 21 ^{st}$ chromosome / autosomal chromosome extra |
| Sterile female | Sterile male or sterile female |
| Rudimentary ovaries / lack of secondary sexual characters / Short stature and underdeveloped feminine character | Affected are short statured with small round head / furrowed tongue / physical, psychomotor and mental development is retarded / partially open mouth / broad flat face / any other relevant symptoms |
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