Question

Synthesis of RNA and protein takes place in which phase of the cell cycle?
A. S-phase
B. M-phase
C. Phase
D. Metaphase

Answer 1

Hint: RNA and Protein Synthesis is related to the synthesis phase of cell cycle. The Cell Cycle has four phases $G_1$, S, $G_2$ and Mitotic Phase.

Complete answer
Cell is a complete entity which can perform all the life processes such as nutrition, excretion, respiration, reproduction etc. A cell undergoes cell division which involves a huge preparation. The cell divides and results in the formation of two daughter cells. The division takes place at the M Phase of life cycle. Cell cycle is broadly categorized into Interphase ($G_1$, S and $G_2$ Phase) and Mitotic Phase (Cell Division Phase).

$G_1$ or Gap 1 Phase is the very first phase of the cell cycle which immediately begins with the formation of new daughter cells. This phase is also known as the growth phase since the cell grows in size in this phase. Along with growth, desired RNA and protein is synthesized in this phase. $G_1$ Phase is followed by the S phase of the cell cycle.

S Phase is known as synthesis phase which is the bridging phase between $G_1$ and $G_2$ Phase. During this phase cell DNA is replicated and results in the duplication of DNA before the next cell division. This is the most critical phase of the cell cycle and the synthesis of DNA needs to be perfect. S Phase if followed by the $G_2$ Phase.

$G_2$ Phase is also known as Gap 2 phase during which again the cell grows in size but this time at a faster rate. $G_2$ Phase is also the very crucial phase since here the final checking of the DNA duplication is done for any genetic error. This is the final stage before the cell undergoes the next division. The genetic errors are checked and rectified at this stage.

Metaphase is one of the phases of M-Phase of cell division which start after the completion of prophase and followed by anaphase. During this phase the chromosomes line up themselves along the metaphase plate.

The correct answer is “C” $G_1$ Phase.

Note: RNA is synthesized at all the stages of interphase and not only at S phase. Proteins are synthesized at $G_1$ and $G_2$ phase of life cycle.