Answer:
To answer the questions related to the diagram representing a stage during mitotic cell division in an animal cell, follow these steps:
(a) **Identify the stage**:
- The stage depicted in the diagram is likely Metaphase of mitosis.
- Reason: In metaphase, chromosomes align along the metaphase plate (equatorial plate) at the center of the cell, which matches the arrangement seen in the diagram.
(b) **Name the parts labelled 1, 2, 3, and 4**:
- 1: Chromosomes
- 2: Spindle fibers (also called microtubules)
- 3: Centromere
- 4: Centrioles (part of the centrosome)
(c) **Function of part 3 (Centromere)**:
- The centromere is a specialized region of a chromosome where sister chromatids are joined together.
- It serves as an attachment point for spindle fibers during cell division, ensuring proper segregation of chromatids.
(d) **Name the stage that comes just after Metaphase**:
- The stage that follows Metaphase is Anaphase.
- In Anaphase, the sister chromatids of each chromosome separate and move towards opposite poles of the cell.
**Well-labelled diagram of Anaphase**:
In Anaphase:
- The centromeres split, separating the sister chromatids.
- The spindle fibers (microtubules) pull the chromatids towards opposite ends of the cell.
- The cell elongates as the separated chromatids move towards the poles.
Here's a simplified representation of Anaphase:
```
___
/ \
___| 1 | 1 |___
/ \
____| 2 | | 2 |____
/ \ / \
| | | |
4 | | | | 4
| | | |
\ / \ /
\_______/ \_______/
Legend:
1 - Separated chromatids
2 - Spindle fibers (microtubules)
4 - Centrioles/centrosomes
```
In this diagram:
- Chromatids (labelled as 1) are shown separated and being pulled towards opposite poles by spindle fibers (labelled as 2).
- Centrioles (labelled as 4) are involved in organizing the spindle fibers.
This representation illustrates the key events and structures observed during Anaphase of mitotic cell division in an animal cell.
