Metaphase: Chromosome Structure & Alignment — NEET Biology
✅ Asked in NEET 2022With respect to metaphase, which of the following statements is incorrect? [NEET -2022]
With respect to metaphase, which of the following statements is incorrect? [NEET -2022]
Select the incorrect statement with reference to mitosis:
Spindle fibres attach on to (NEET I 2016)
Answer & NCERT explanation
Correct answer: D — Metaphase chromosomes are made up of four sister chromatids held together by centromere
Metaphase chromosomes consist of two sister chromatids joined at the centromere, not four. Each chromosome has duplicated during S phase, creating two identical sister chromatids. The statement about four sister chromatids is incorrect - this would require two rounds of DNA replication without cell division. All other options correctly describe metaphase: chromosomes align at the equator, nuclear envelope completely disintegrates, and chromosomes are maximally condensed for proper segregation.
Read more NCERT concept on the PYQ
The complete disintegration of the nuclear envelope marks the start of the second phase of mitosis, hence the chromosomes are spread through the cytoplasm of the cell. By this stage, condensation of chromosomes is completed and they can be observed clearly under the microscope. This then, is the stage at which morphology of chromosomes is most easily studied. At this stage, metaphase chromosome is made up of two sister chromatids, which are held together by the centromere. Small disc-shaped structures at the surface of the centromeres are called kinetochores. These structures serve as the sites of attachment of spindle fibres to the chromosomes that are moved into position at the centre of the cell. Hence, the metaphase is characterised by all the chromosomes coming to lie at the equator with one chromatid of each chromosome connected by its kinetochore to spindle fibres from one pole and its sister chromatid connected by its kinetochore to spindle fibres from the opposite pole. The plane of alignment of the chromosomes at metaphase is referred to as the metaphase plate. The key features of metaphase are:
Metaphase is characterized by chromosomes aligning at the cell's equator (metaphase plate), with each chromosome consisting of two sister chromatids joined at the centromere. Kinetochores on the centromere attach spindle fibers that pull sister chromatids toward opposite poles. Students often confuse metaphase chromosomes with interphase chromosomes—remember that metaphase chromosomes are fully condensed and visible under microscope, consisting of TWO sister chromatids, not one. The critical detail NTA tests: kinetochores are disc-shaped structures on centromeres (not the centromere itself), and each sister chromatid is attached to spindle fibers from opposite poles. Know the exact arrangement of chromosomes at the metaphase plate for diagram-based questions.
What does NCERT say about complete disintegration nuclear envelope?
Has this concept appeared in NEET?
Which chapter is this from?
Through deep analysis of NEET and NTA, 88 of 90 questions from the NEET 2026 paper were matched straight from the MedicNEET Biology question bank.
88/90MedicNEET's Biology question bank is built from the same NCERT lines NTA picks repeatedly. Not random MCQs — questions crafted exactly like NTA crafts them.