Solved Examples on Cell Cycle and Cell Division

(1) Select the correct option with respect to mitosis

[CBSE PMT’2011]

(a) Chromatids separate but remain in the centre of the cell in anaphase.

(b) Chromatids start moving towards opposite poles in telophase.

(c) Golgi complex and endoplasmic reticulum are still visible at the end of prophase.

(d) Chromosomes move to the spindle equator and get aligned along equatorial plate in metaphase.

Answer: d

Explanation: In mitosis, chromosomes move to the equator and get aligned along equatorial plate in metaphase.

(2) At metaphase, chromosomes are attached to the spindle fibres by their

[CBSE PMT’2011 M]

(a) satellites

(b) secondary constrictions

(c) kinetochores

(d) centromere

Answer: c

Explanation: Kinetochores are large protein complexes that bind the centromeres of chromosomes to the microtubules of mitotic spindle fibres during metaphase in the cell cycle.

(3) During gamete formation, the enzyme recombinase participates during

[CBSE PMT’2012 S]

(a) Metaphase – I

(b) Anaphae – I

(c) Prophase – I

(d) Prophase – II

Answer: c

Explanation: Recombinase enzyme catalyses the exchange of short pieces of DNA between two long DNA strands particularly the exchange of homologous regions between the paired maternal and paternal chromosomes in prophase–I.