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प्रश्न
Write a note on Down’s syndrome.
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उत्तर
Down syndrome:
- Individuals suffering from Down syndrome will have 47 chromosomes instead of the normal number 46.
- 21st Trisomy occurs due to non-disjunction or failure of separation of chromosomes (autosomes) during gamete formation.
- Following are the symptoms of Down syndrome:
- Mild or moderate mental retardation and poor skeletal development.
- Distinct facial features like small head, ears, and mouth.
- The face is typically flat and rounded with a flat nose, open mouth, and protruding tongue.
- Eyes slant up and out with internal epicanthal folds.
- Flat hands and stubby fingers, the palm is broad with a single palmer crease.
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संबंधित प्रश्न
Identify ‘a’, ‘b’, ‘c’, ‘d’, ‘e’ and ‘f’ in the table given below:
| S. No. | Syndrome | Cause | Characteristics of affected individuals | Sex (male/female/both) |
| 1. | Down’s | Trisomy of 21 |
‘a’ |
‘b’ |
| 2. | ‘c’ | XXY | Overall masculine development | ‘d’ |
| 3. | Turner’s | 45 with XO |
‘e’ |
‘f’ |
What do sex linked traits appear in males than in females?
Webbed neck is characteristic of ______ syndrome.
Give a detail account of thalassemia.
In Klinefelter syndrome, an extra chromosome is a result of non-disjunction of X-chromosome during ____________.
Following list indicates various genetic diseases. Identify the diseases that are not caused due to single gene defect.
Huntington's chorea, alkaptonuria, Sickle cell anaemia, Down syndrome, thalassemia, Taysachs disease, Turner syndrome, cystic fibrosis, haemophi Lia, Klinefelter syndrome, albinism
If both parents are carriers for thalassaemia, which is an autosomal recessive disorder, what are the chances of pregnancy resulting in an affected child?
Read the following and answer from given below:
Turner's syndrome is an example of monosomy. It is formed by the union of an allosome-free egg and a normal 'X' containing sperm or a normal egg and an allosome-free sperm. The individual has 2n = 45 chromosomes (44 + X0) instead of 46. Such individuals are sterile females who have rudimentary ovaries, underdeveloped breasts, small uterus, short stature, webbed neck, and abnormal intelligence. They may not menstruate or ovulate. This disorder can be treated by giving female sex hormones to women from the age of puberty to make them develop breasts and have menstruation. This makes them feel more normal.
Turner's syndrome is a/an ______
Why is the frequency of red-green colour blindness is many times higher in males than that in females?
Trisomy of 21st chromosome leads to a disorder ______.
