Multiple Choice QuestionsThe trisomy for 21st chromosome is called
Down's syndrome
Turner's syndrome
Sickle cell anaemia
Klinfelter's syndrome
A.
Down's syndrome
| Abnormality | Cause | Characteristic |
| Down's Syndrome | Trisomy of 21st chromosome (45 A + XX/ XY) | Mental retardation, prominent head, flattened nasal bridge, open mouth, short stature etc |
| Turner's Syndrome | Non- disjunction of sex chromosome (2n = 45; 44A +XO) | Sterile female, webbed neck, no breast development, no menstruation or egg production |
| Klinefelter's Syndrome | Non- disjunction of sex chromosomes (2n = 47; 44A + XXY) | Sterile male with low IQ, testes underdeveloped. |
| Sickle cell anaemia | Molecular gene mutation of gene HbA | Sickle shaped RBCs, do not transport O2 efficiently |
If root of a flowering plant has 24 chromosomes, then its gamete has how many chromosomes?
24
12
4
8
Balbiani rings are the structural features of
allosomes
polytene chromosomes
autosomes
Lampbrush chromosomes
X- linked recessive gene is
always expressed in male
always expressed in femlae
lethal
sub- lethal
1 : 2 : 1 phenotypic and genotypic ratio is found in
complementary genes
blending inheritance
multiple alleles
pseudo alleles
A man and a woman, who do not show any apparent signs of a certain inherited disease, have seven children (2 daughters and 5 sons). Three of the sons suffer from the given disease but none of the daughters are affected. Which of the following mode of inheritance do you suggest for this disease?
Autosomal dominant
Sex-linked dominant
Sex-limited recessive
Sex-linked recessive
A haemophilic woman marries a normal man then
all the children will be normal
all the sons will be haemophilic
all the girls will be haemophilic
half girls will be haemophilic
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