Draw the Cell Cycle Diagram.
• Basic pie chart with stages of interphase, mitosis, and cytokinesis (draw in the center of page)
- Add the chromosome number before and after s phase of interphase
- Add the chromatid number for each stage before and after s phase of interphase .
Add the 3 checkpoints and the name of a main tumor suppressor gene
The Correct Answer and Explanation is :
Here is a cell cycle diagram, illustrating the stages of Interphase (G1, S, G2), Mitosis (Prophase, Metaphase, Anaphase, Telophase), and Cytokinesis. It includes the chromosome and chromatid numbers before and after the S phase of Interphase, as well as the 3 checkpoints (G1, G2, M), and the tumor suppressor gene p53.
Explanation:
- Interphase:
- G1 Phase (Gap 1): This is the cell’s first growth phase, where it grows in size and synthesizes proteins and RNA. The chromosome number is 46, and each chromosome consists of a single chromatid.
- S Phase (Synthesis): The DNA is replicated during this phase. The chromosome number remains at 46, but each chromosome now consists of two identical sister chromatids.
- G2 Phase (Gap 2): This is the final growth phase before mitosis, where the cell continues to grow and prepares the necessary proteins for cell division.
- Mitosis:
- Prophase: The chromatin condenses into visible chromosomes, each consisting of two sister chromatids. The nuclear membrane begins to dissolve.
- Metaphase: Chromosomes align at the cell’s equator.
- Anaphase: The sister chromatids are pulled toward opposite poles of the cell.
- Telophase: The chromosomes de-condense, and the nuclear membrane reforms.
- Cytokinesis: This is the final stage where the cytoplasm divides, forming two daughter cells.
Checkpoints:
- G1 Checkpoint: Checks for DNA damage, cell size, and the environment. If the conditions are unfavorable, the cell may enter a resting state (G0).
- G2 Checkpoint: Ensures DNA replication is complete and checks for DNA errors before mitosis.
- M Checkpoint: Occurs during mitosis to check that chromosomes are correctly aligned and attached to spindle fibers before proceeding.
The tumor suppressor gene p53 plays a critical role in controlling these checkpoints and preventing the cell from dividing when damaged, thus protecting against cancer development.