Question

In eukaryotic cell cycle, cell fusion experiments show that :-

• A. When an S phase cell is fused with a G${}_1$ phase cell, G${}_1$ phase cell is stimulated to synthesize DNA
• B. When an S phase cell is fused with a G${}_2$ phase cell, DNA synthesis is induced in G${}_2$ phase cell
• C. When a G${}_1$ phase cell is fused with a G${}_2$ phase cell, DNA synthesis is induced in both G${}_1$ and G${}_2$ phase cells
• D. When a G${}_1$ phase cell is fused with an M phase cell both G${}_1$ and M phase cells are stimulated to synthesise DNA

Answer 1

The correct option is A When an S phase cell is fused with a G${}_1$ phase cell, G${}_1$ phase cell is stimulated to synthesize DNA

S phase is also called as synthetic phase. During S phase, DNA of each chromosome replicates followed by synthesis of histone proteins. If a cell which is in S phase is fused with a cell which is in G${}_1$ phase, DNA synthesis or DNA replication will be induced in the cell which is in G${}_1$ phase. So, the correct answer is option A.