Question

Lampbrush chromosome are found in
A) Salivary glands of Drosophila
B) Salivary glands of silk moths.
C) Oocytes of frog
D) Nucleus of man

Answer 1

Lampbrush chromosomes are giant chromosomes found in animals but not mammals. These chromosomes are large in size and they are found in developing oocytes of mammals. They are mostly used in mapping of DNA sequences and construction of cytological maps.

Complete answer:
INTRODUCTION : Lampbrush chromosomes are active giant chromosomes found in vertebrates, invertebrates. They are mostly found in the oocytes of most vertebrates and spermatocytes of some insects. Oocytes and spermatocytes are produced by meiosis cell division.
A) SALIVARY GLANDS OF Drosophila : polytene chromosomes are large chromosomes found in salivary glands of Drosophila. They are referred to as the salivary gland chromosome. They provide a high level of function in salivary glands.
B) SALIVARY GLANDS OF SILK MOTH : Polytene chromosomes are usually found in salivary glands of silk moth. This type of chromosome is present in silk gland cells of silk moths.
C) OOCYTES OF FROG : Lampbrush chromosomes are present in nuclei of the oocytes of vertebrates such as amphibians, reptiles and birds. They are the largest chromosome characterized by the presence of a loopy and brushy appearance.
D) NUCLEUS OF MAN : Lampbrush chromosomes are absent in mammals. Nucleus is a membrane bound organelle that contains a cell's chromosome. Linear type of chromosome is found in the nucleus of every cell.

Hence option C is the correct answer.

Note :
Lampbrush chromosomes are large chromosomes present in eukaryotes. They are referred to as meiotic chromosomes. It consists of two chromatids called sister chromatids. The lateral type of chromosome contains DNA molecules. It is an active site for synthesis of RNA.