Question

Identify the phase at which most organelles duplicates.
A. M phase
B. $G_1$ phase
C. $G_0$ phase
D. $G_2$ phase

Answer 1

Hint: The duplication of organisms is done through cell division. The mature cell divides to form two daughter cells. These cells resemble the parents. These sequences of events occur during cell proliferation and cell growth are called the cell cycle. It is further divided into several phases and results in successful cell duplication.

Complete answer:
The required period to complete one cell cycle is termed as generation time. It starts from the beginning of one cell division to the beginning of the next. In humans, it lasts for around 24 hours and about 90 minutes in Yeast.
There are two basic phases:
- Interphase ( $G_1$ phase, S phase, $G_2$ Phase, $G_0$ phase, M phase)
- M phase (Mitosis phase/Dividing phase)

Interphase- It is a metabolically active phase in which the cell prepares itself for the next cell division. It involves the following three phases-
> $G_1$ phase/Post mitotic/pre DNA synthetic phase- Intensive cellular synthesis, cell size increases, synthesis of rRNA, ribosomes, and proteins.

> S phase- It involves the period during which DNA synthesis takes place.

> $G_2$ phase/Pre mitotic/post-synthetic/Gap II- It involves the duplication of organelles and synthesis of certain proteins occurs. Cells that do not undergo further division enter the $G_0$ phase.

> M phase- It involves Karyokinesis(a division of the nucleus) and cytokinesis(a division of the cytoplasm).

Hence, the correct answer is option (D).

Note: $G_0$ phase occurs when cells do not divide further. It exits the previous phase and enters the $G_0$ phase. It is also known as the quiescent stage. Cells in this stage actually remain metabolically active but they do not undergo reproduction. M phase represents the Mitotic phase or the dividing phase.