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The contrasting pairs of factors in Mendelian crosses are called

A) allelomorphs B) multiple alleles C) paramorphs D) alloloci Answer: A) allelomorphs Explanation: The contrasting pairs of factors in... View Article

In human beings 45 chromosomes/ single X/XO abnormality causes

A) Kinefelter’s syndrome B) Down’s syndrome C) Edward’s syndrome D) Turner’s syndrome Answer:D) Turner’s syndrome... View Article

A colour blind mother and normal father would have

A) colour blind sons and daughters B) colour blind sons and normal/carrier daughters C) all normal D) all colour blind Answer:B) colour blind... View Article

An organism with two identical alleles is

A) hybrid B) dominant C) homozygous D) heterozygous Answer: C) homozygous Explanation: Two identical alleles of a gene present on homologous... View Article

Of a normal couple, half the sons are haemophiliac while half the daughters are carriers. The gene is located on

A) Y chromosome of father B) X chromosome of father C) both the X chromosomes of mother D) one X chromosome of mother... View Article

Of both normal parents, the chance of a male child becoming colour blind are

A) possible only when all the four grandparents had normal vision B) possible only when mother’s father was colour blind C) possible only... View Article

The colour blindness is more likely to occur in males than in females because

A) genes for characters are located on the X chromosomes B) the trait is dominant in males and recessive in females C) the Y... View Article

Albinism is a congenital disorder resulting from the lack of which enzyme?

A) Xanthine oxidase B) Tyrosinase C) Fructokinase D) Catalase Answer:B) Tyrosinase Explanation: Albinism is caused due to the lack of melanin... View Article

A child’s blood group is ‘O’. The parent’s blood groups cannot be

A) A and A B) A and B C) AB and O D) B and O Answer:C) AB and O Explanation: Children inherit two alleles of a gene from both parents. Parents... View Article

The most striking example of point mutation is found in a disease called

A) sickle cell anaemia B) Down’s syndrome C) night blindness D) thalassaemia Answer:A) sickle cell anaemia Explanation: Point mutation... View Article

Crossing over in diploid organism is responsible for

A) recombination of linked alleles B) segregation of alleles C) linkage between genes D) dominance of genes Answer:A) recombination of linked... View Article

When a single gene influences more than one trait it is called

A) pleiotropy B) pseudodominance C) epistasis D) none of these Answer:A) pleiotropy Explanation: When a single gene influences multiple... View Article

In human beings, multiple genes are involved in the inheritance of

A) skin colour B) sickle cell anaemia C) phenylketonuria D) colour blindness Answer:A) skin colour Explanation: Skin colour is an example... View Article

Haemophilic man marries a normal woman.Their offsprings will be

A) all boys haemophilic B) all haemophilic C) all girls carrier D) all girls haemophilic Answer: C) all girls carrier Explanation:... View Article

A gene pair hides the effect of another gene. The phenomenon is called

A) segregation B) dominance C) mutation D) epistasis Answer:D) epistasis Explanation: When a gene masks the phenotypic effect of another... View Article

According to Mendelism, which character shows dominance?

A) Green colour in seed coat B) Terminal position of flower C) Green pod colour D) Wrinkled seeds Answer: C) Green pod colour Explanation:... View Article

Independent assortment of genes does not takes place when

A) genes are linked and located on same chromosome B) genes are located on homologous chromosomes C) genes are located on non homogenous... View Article

Two nonallelic genes produces the new phenotype when present together but fail to do so independently then it is called

A) polygene B) epistasis C) complementary gene D) non complementary gene Answer: C) complementary gene Explanation: Complementary genes are... View Article

A diseased man marries a normal woman. They have three daughters and five sons. All the daughters were diseased and the sons were normal. The gene of this disease is

A) sex linked recessive B) sex linked dominant C) autosomal dominant D) sex limited character Answer:B) sex linked dominant Explanation: It is... View Article

A gene is said to be dominant if

A) it expresses its effect only in heterozygous condition B) it expresses its effect only in homozygous state C) it never expresses its effect... View Article

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