Biology : Principles of Inheritance and Variation

The trisomy for 21st chromosome is called

• Down's syndrome

• Turner's syndrome

• Sickle cell anaemia

• Klinfelter's syndrome

Chromosome complement with 2n - 1 is called

• monosomy

• nullisomy

• trisomy

• tetrasomy

L- shaped chromosomes are also called

• acrocentric

• telocentric

• sub- metacentric

• None of these

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

Which of the following is a test cross?

• Tt $\times$tt

• TT $\times$tt

• Tt $\times$Tt

• tt $\times$tt

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