Question

Nuclear membrane is formed around the groups of daughter chromosomes during the telophase by
(a) Endoplasmic reticulum
(b) Lysosomes
(c) Golgi apparatus
(d) Microbodies

Answer 1

Hint: The nuclear membrane emerges from a tubular- shaped cell organelle, which is present in the form of a network. DNA- binding proteins present in that organelle do the whole process, during the event of cell division. These organelles also help in the formation of organelles that cause cell death.

Complete answer:
The Endoplasmic reticulum forms the nuclear membrane around the groups of daughter chromosomes during the telophase. The chromatin fibers play an important role in reshaping of the endoplasmic reticulum during nuclear membrane formation.
- Features of Endoplasmic Reticulum:
- Endoplasmic Reticulum is a well- developed microscopic network of interconnected cisternae, tubules and vesicles present throughout the cytoplasm.
- In the plant cells, during cytokinesis, the Endoplasmic Reticulum and Golgi body align at the equator.
- The Endoplasmic Reticulum was observed by Garnier in 1897 A.D. but its ultrastructure was given by Porter, Claude, and Fullam in 1945 A.D.
- The Endoplasmic Reticulum is absent from the prokaryotes but is present in all the eukaryotes except germinal cells and mature mammalian erythrocytes.
- Based on the presence and absence of the ribosomes the Endoplasmic Reticulum is of two types- Smooth or Agranular Endoplasmic Reticulum (SER) , and Rough or Granular Endoplasmic Reticulum (RER).
- The Endoplasmic Reticulum acts as a circulatory system and helps in the transportation of materials in a directional flow.
- The Endoplasmic Reticulum is a component of the cytoplasmic vacuolar system which acts as a cytoskeleton and provides mechanical support and shape to the cell.
- The Endoplasmic Reticulum helps in the formation of the primary lysosome with hydrolytic enzymes.
So, the correct answer is, ‘Endoplasmic Reticulum.’

Note: A nuclear membrane is a bilayered envelope about 90 Å thick lipoprotein (lipid and protein) and trilaminar structure.
- The outer membrane is called ectokaryotheca, is studded with ribosomes on its cytoplasmic surface, and is continuous with Rough Endoplasmic Reticulum. The inner membrane is called endokaryotheca, and is without ribosomes.