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The genotype of a plant showing the dominant phenotype can be determined by

A) dihybrid cross B) test cross C) back cross D) pedigree analysis Answer: B) test cross Explanation: Test cross involves crossing... View Article

Select the correct statement from the ones given below with respect to dihybrid cross.

A) Genes far apart on the same chromosome show very few recombinations B) Tightly linked genes on the same chromosomes... View Article

Test cross in plants or in Drosophila involves crossing

A) between two F1 hybrids B) between two genotypes with recessive trait C) between two genotypes with dominant trait D)... View Article

Which one of the following conditions of the zygotic cell would lead to the birth of a normal human female child?

A) Only one Y chromosome B) Two X chromosomes C) One X and one Y chromosome D) Only one X... View Article

Which one of the following conditions correctly describes the manner of determining the sex?

A) XO type of sex chromosomes determine male sex in grasshopper B) Homozygous sex chromosomes (ZZ) determine female sex in... View Article

When two unrelated individuals or lines are crossed, the performance of F1 hybrid is often superior to both its parents. This phenomenon is called

A) transformation B) heterosis C) metamorphosis D) splicing Answer: B) heterosis Explanation: Improved quality or function in the hybrid is called... View Article

A test cross is carried out to

A) predict whether two traits are linked B) determine the genotype of a plant at F2 C) determine whether two... View Article

F2 generation in a Mendelian cross showed that both genotypic and phenotypic ratios are the same as 1 : 2 : 1. It represents a case of

A) dihybrid cross B) codominance C) monohybrid cross with incomplete dominance D) monohybrid cross with complete dominance Answer: C) monohybrid cross... View Article

Down’s syndrome in humans is due to

A) three copies of chromosome 21 B) three ‘X’ chromosomes C) two ‘Y’ chromosomes D) monosomy Answer:A) three copies of... View Article

If two persons with ‘AB’ blood group marry and have sufficiently large number of children, these children could be classified as ‘A’ blood group: ‘AB’ blood group : ‘B’ blood group in 1 : 2 : 1 ratio. Modern technique of protein electrophoresis reveals presence of both ‘A’ and ‘B’ type proteins in ‘AB’ blood group individuals.

A) complete dominance B) partial dominance C) incomplete dominance D) codominance Answer:D) codominance Explanation: It is an example of codominance.... View Article

If both parents are carriers for thalassemia, which is an autosomal recessive disorder, what are the chances of pregnancy resulting in an affected child?

A) 100% B) 50% C) 25% D) Nil Answer: C) 25% Explanation: Thalassemia is an autosomal recessive disease. The carrier of... View Article

A human female with Turner’s syndrome

A) has one additional X chromosome B) has 45 chromosomes with XO C) is able to produce children with normal... View Article

Fruit colour in squash is an example of

A) dominant epistasis B) recessive epistasis C) inhibitory genes D) complementary genes Answer:A) dominant epistasis Explanation: Epistasis is the interaction... View Article

An abnormal human baby with ‘XXX’ sex chromosomes was born due to

A) fusion of two sperms and one ovum B) fusion of two ova and one sperm C) formation of abnormal... View Article

How many pairs of contrasting characters in pea plants were studied by Mendel in his experiments?

A) 7 B) 8 C) 5 D) 6 Answer: A) 7 Explanation: Mendel conducted hybridisation experiments on pea plants from 1856-1863.... View Article

A man with blood group ‘A’ marries a woman with blood group ‘B’. What are all the possible blood groups of their offsprings?

A) O only B) A, B, AB and O C) A and B only D) O only Answer:B) A, B,... View Article

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