Question

In which phase proteins for spindle fibre formation are synthesized?

• A. G${}_1$-phase
• B. G${}_2$-phase
• C. S-phase
• D. Anaphase

Answer 1

Answer: (B)

G${}_2$-phase

In G${}_2$-phase proteins for spindle fibre formation are synthesized. It is the third, final and usually the shortest subphase during interphase within the cell cycle in which the cell undergoes a period of rapid growth to prepare for mitosis. It follows successful completion of DNA synthesis and chromosomal replication during the S-phase and occurs during a period of often four to five hours (for human cells). Although chromosomes have been replicated they cannot yet be distinguished individually because they are still in the form of loosely packed chromatin fibres. The G${}_2$-phase prepares the cell for mitosis (M phase) which is initiated by prophase.