Question
Question: Which one of the following organelle is responsible for the formation of aster in cell division ? ...
Which one of the following organelle is responsible for the formation of aster in cell division ?
A. Chromosome
B. Lysosome
C. Ribosome
D. Centrosome
Solution
Aster is a star-like cellular structure that carries centrosomes and its associated microtubules throughout the first section of mitotic cellular division that present only in animals and lower plants. Asters are radial microtubule arrays found in animal cells and plant cells.
Complete answer:
Aster is formed around every pair of centrioles during mitotic cell division. Asters facilitate to govern chromosomes throughout the division to confirm that every cell has the accurate complement of chromosomes. It contains astral microtubules which formed from cylindrical microtubules known as centrioles. Centrioles are found inside the centrosome that is situated close to the cell nucleus that forms the spindle poles.
Asters are the largest of the three main cytoskeletal components which are - microfilaments, intermediate filaments and microtubules and radiate from the centrosphere. Centrosomes are formed before Aster formation. These are also cytoskeleton structures consisting of two bundles of microtubules called centrioles which are arranged at right angles to each other and stay near the nuclear envelope. Before starting mitosis or meiosis cell division, the centrosomes are divided into two equal daughter centrosomes that move towards the opposite side of the nucleus.
By the starting of either mitosis or meiosis cell division, centrosomes forms two new structures are as follows-
1. Spindle fibers- It connects both sister centrosomes.
2. Asters- It is generated from the centrosome. It provides support and guide chromosomes to place at the right position in the nuclear envelope.
Hence, the correct answer is option (A).
Note: Asters are star shaped structures that consist of chromosomes and related microtubules. It guides the chromosome to arrange at the right position during mitotic and meiosis cell division. It is made up of microfilaments , and microtubules.