Question

The persistent nuclear membrane and intranuclear spindle are characteristic of
A. Cryptomitosis
B. Endomitosis
C. Free nuclear division
D. Mitosis

Answer 1

Hint: The intranuclear spindle, as the name indicates, is the spindle that is formed inside the nucleus. It takes place only when centriole is not present inside the cell.

Complete answer:
Cryptomitosis or promitosis is known as the primitive type of mitosis. It is the characteristic feature of certain protozoa during binary fission such as amoeba. In this mitosis, the nuclear membrane does not disappear but it is persistent throughout the division. Even the spindle formation takes place inside the nucleus due to the absence of centriole.
Endomitosis is a form of mitosis in which duplication of chromosomes takes place without the division of the nucleus or cell, resulting in numerous copies of chromosomes within the cell. Thus, this type of mitosis leads to the generation of polyploidy conditions. It takes place in the salivary glands of flies, hepatocyte of rodents.
Free nuclear division is one in which karyokinesis is not followed by cell division leading to the generation of coenocytic conditions. It takes place in the endosperm, acellular slime molds.
Mitosis is the process in which there is a division of a single cell into two identical daughter cells and takes place only in eukaryotic cells. It includes five phases- interphase, prophase, metaphase, anaphase, and telophase. Mitosis serves the purpose for growth and to replace dead or worn-out cells.

Hence, the correct option is (A).

Note: Crypto Mitosis is a primitive form of mitosis in which an achromatic spindle or intranuclear spindle exists and also the nuclear membrane does not disappear, thereby forming a persistent nuclear membrane throughout the division process.