Cell cycle and Cell Divisions MCQs for NEET — Botany Questions with Answers

The NCERT text states, 'Mitotic divisions in the meristematic tissues – the apical and the lateral cambium, result in a continuous growth of plants throughout their life.' Meristematic tissues are responsible for growth.

The context clearly states, 'Since the number of chromosomes in the parent and progeny cells is the same, it is also called as equational division.' Options 1 and 2 describe meiosis, and option 4 is incorrect for mitosis.

The NCERT text mentions, 'However, in some lower plants and in some social insects haploid cells also divide by mitosis.' and also 'However, there are few exceptions to this where haploid cells divide by mitosis, for example, male honey bees.' This indicates that it's not a universal phenomenon but specific exceptions.

The NCERT states, 'Cell growth results in disturbing the ratio between the nucleus and the cytoplasm. It therefore becomes essential for the cell to divide to restore the nucleo-cytoplasmic ratio.' This highlights the importance of maintaining an optimal volume for efficient functioning.

The text states, 'In animals, mitotic cell division is only seen in the diploid somatic cells. However, there are few exceptions to this where haploid cells divide by mitosis, for example, male honey bees.' So, the general rule is diploid somatic cells, with exceptions.

The text states, 'Mitosis usually results in the production of diploid daughter cells with identical genetic complement.' This is a defining characteristic of mitosis or equational division.

The context describes $G_0$ phase as an 'inactive stage called quiescent stage (G0) of the cell cycle. Cells in this stage remain metabolically active but no longer proliferate unless called on to do so depending on the requirement of the organism.'

The megaspore mother cell (MMC) undergoes meiosis to produce four megaspores. Then, as stated, 'Only the functional megaspore develops into the female gametophyte (embryo sac).' This development involves mitotic divisions of the haploid functional megaspore to form the multicellular embryo sac, without further meiotic events.

The text mentions, 'The cells of the upper layer of the epidermis, cells of the lining of the gut, and blood cells are being constantly replaced.' Heart cells do not appear to exhibit division, and mature RBCs do not divide. Neurons generally do not divide after maturation.

The NCERT states, 'The growth of multicellular organisms is due to mitosis.' Mitosis increases cell number, leading to growth, while meiosis is for reproduction and DNA replication is part of the cell cycle but not the sole driver of organismal growth.