Polytene chromosomes were first reported by EG Balbiani in 1881. They are quite common in salivary glands of insects and are therefore popularly called salivary gland chromosomes. Polytene chromosomes also occur in other organs of insects antipodal cells (of embryo sac), endosperm cells and suspensor cell of embryo. The chromosomes can reach length of 200 µm and contain 1000 to 16000 times DNA as compared to the ordinary somatic chromosomes. The giant chromosomes are formed by somatic pairing between homologous chromosomes, and repeated replication (endomitosis) of their chromatids.

Correct Option: D

Polytene chromosomes were first reported by EG Balbiani in 1881. They are quite common in salivary glands of insects and are therefore popularly called salivary gland chromosomes. Polytene chromosomes also occur in other organs of insects antipodal cells (of embryo sac), endosperm cells and suspensor cell of embryo. The chromosomes can reach length of 200 µm and contain 1000 to 16000 times DNA as compared to the ordinary somatic chromosomes. The giant chromosomes are formed by somatic pairing between homologous chromosomes, and repeated replication (endomitosis) of their chromatids.

The mathematical expression to calculate allele frequency can be given as p + q = 1. Where p represents the frequency of dominant allele and q represents the frequency of recessive allele. The bionomial expression of Hardy Weinberg’s law to calculate genotype frequency is
p² + 2pq + q² = 1
where p² = homozygous dominant
2pq = heterozygous dominant
q² = homozygous recessive.
Frequency of heterozygous individuals = 2 × 0.6 × 0.4 = 0.48.

Correct Option: D

The mathematical expression to calculate allele frequency can be given as p + q = 1. Where p represents the frequency of dominant allele and q represents the frequency of recessive allele. The bionomial expression of Hardy Weinberg’s law to calculate genotype frequency is
p² + 2pq + q² = 1
where p² = homozygous dominant
2pq = heterozygous dominant
q² = homozygous recessive.
Frequency of heterozygous individuals = 2 × 0.6 × 0.4 = 0.48.

Male sterility in plants can be controlled by nuclear genes or cytoplasm or by both. Three different mechanisms for control of male sterility in plants are:
(i) Genetic male sterility;
(ii) Cytoplasmic male sterility;
(iii) Cytoplasmic genetic male sterility.
In Maize the genes for cytoplasmic control of male sterility are located in cytoplasm.

Correct Option: A

Male sterility in plants can be controlled by nuclear genes or cytoplasm or by both. Three different mechanisms for control of male sterility in plants are:
(i) Genetic male sterility;
(ii) Cytoplasmic male sterility;
(iii) Cytoplasmic genetic male sterility.
In Maize the genes for cytoplasmic control of male sterility are located in cytoplasm.

It would make only two types of gametes, these are ABC & AbC.

Correct Option: C

It would make only two types of gametes, these are ABC & AbC.

Phenotype is the appearance of one organism while genotype is the gene complement it has from its ancestors. These genes only show their effect in phenotype but environment also plays an important role in this. Hence phenotype is a result of genotype and environmental interaction.

Correct Option: C

Phenotype is the appearance of one organism while genotype is the gene complement it has from its ancestors. These genes only show their effect in phenotype but environment also plays an important role in this. Hence phenotype is a result of genotype and environmental interaction.