Mitosis accomplishes not only the segregation of duplicated chromosomes into daughter nuclei (karyokinesis), but the cell itself is divided into two daughter cells by the separation of cytoplasm called cytokinesis at the end of which cell division gets completed. In an animal cell, this is achieved by the appearance of a furrow in the plasma membrane. The furrow gradually deepens and ultimately joins in the centre dividing the cell cytoplasm into two. Plant cells however, are enclosed by a relatively inextensible cell wall, therefore they undergo cytokinesis by a different mechanism. In plant cells, wall formation starts in the centre of the cell and grows outward to meet the existing lateral walls. The formation of the new cell wall begins with the formation of a simple precursor, called the cell-plate that represents the middle lamella between the walls of two adjacent cells. At the time of cytoplasmic division, organelles like mitochondria and plastids get distributed between the two daughter cells. In some organisms karyokinesis is not followed by cytokinesis as a result of which multinucleate condition arises leading to the formation of syncytium (e.g., liquid endosperm in coconut).
Which of the following statements regarding cytokinesis are NOT correct? S1: In animal cells, cytoplasmic division is achieved by the appearance and centripetal deepening of a furrow in the plasma membrane. S2: Plant cells, possessing an inextensible cell wall, typically form a cell plate that grows centrifugally from the center. S3: The cell plate formed during plant cytokinesis represents the future middle lamella between the walls of two adjacent cells. S4: In organisms where karyokinesis is followed by cytokinesis, the distribution of organelles like mitochondria occurs before the cytoplasmic division. S5: Syncytium formation is a characteristic feature of plant cells due to their rigid cell walls preventing furrow formation. S6: The process of cytokinesis ensures the segregation of duplicated chromosomes into daughter nuclei.
MedicNEET's Biology question bank is built from the same NCERT lines NTA picks repeatedly. Not random MCQs — questions crafted exactly like NTA crafts them.