Botany MCQs for NEET — Practice Questions with Answers

When a heterozygous yellow-seeded plant (Yy) is crossed with a green-seeded plant (yy), the offspring (F₁ generation) can be YY (yellow), Yy (yellow), or yy (green). The ratio of yellow to green seeds can be determined using a Punnett square. The expected ratio is 1:1, meaning 50% yellow and 50% green seeded plants.

The ABO blood grouping system is named so because type 'O' blood has neither A nor B antigens on the surface of the red blood cells (RBCs). This is why it is referred to as 'O,' indicating the absence of these antigens.

Mendel's law of dominance does not explain the phenomenon where alleles do not show any blending and both characters recover as such in the F₂ generation. This is explained by the law of segregation, which states that allele pairs separate randomly, so that each gamete receives one allele of each pair.

A test cross is used to determine the genotype of a plant showing a dominant phenotype. In a test cross, the individual with the dominant phenotype (but unknown genotype) is crossed with an individual that is homozygous recessive for the trait in question. If any offspring display the recessive phenotype, the dominant phenotype parent must be heterozygous. If all offspring display the dominant phenotype, the parent is likely homozygous dominant.

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.