NEET Practice Questions (MCQs) with Answers & Solutions

Mutations can be induced using gamma radiations. Gamma rays are a form of ionizing radiation which have high energy and the ability to penetrate tissues, causing changes in the DNA sequence, leading to mutations. This method is commonly used in genetic studies to create mutations and study their effects.

A test cross involves crossing the F₁ hybrid with a double recessive genotype. This type of cross helps to determine the genotype of the F₁ hybrid by analyzing the phenotypes of the offspring. If the F₁ hybrid is heterozygous, the offspring will show a 1:1 ratio of dominant to recessive traits.

A normal human female child has two X chromosomes (XX). The presence of two X chromosomes ensures the development of female characteristics. Hence, the zygotic condition leading to the birth of a normal human female child is having two X chromosomes.

A test cross is carried out to determine the genotype of a plant at the F1 generation. By crossing the F1 organism with a homozygous recessive individual, the resulting offspring can reveal whether the F1 organism is homozygous dominant or heterozygous.

The cross between AaBB and aaBB involves a single gene pair (Aa x aa) with another gene pair being homozygous dominant (BB). The resulting genotypic ratio will be 1 AaBB : 1 aaBB. This means that half of the offspring will inherit the dominant 'A' allele and the other half will inherit the recessive 'a' allele, while all will inherit the dominant 'B' allele.

A recessive allele is one that is unable to express its effect in the presence of a dominant allele. In other words, the effect of a recessive allele is masked by the presence of a dominant allele. This is a fundamental concept in Mendelian genetics.