Question

.
A student observed a human cheek cell under a light microscope and made these observations:

The chromatin is condensed.
There is no visible nucleolus.
The spindle fibers are visible.
The nuclear membrane looks like it is disappearing.


Which phase of the cell cycle is this student MOST LIKELY observing?

Prophase

Telophase

Metaphase

Interphase

Answer 1

The observations made by the student suggest that the cell is in **prophase**.

Here’s a breakdown of the reasoning:

- **Condensed chromatin**: During prophase, chromatin fibers condense into visible chromosomes.
- **No visible nucleolus**: The nucleolus typically disappears during prophase.
- **Visible spindle fibers**: The formation of spindle fibers occurs in prophase as the mitotic spindle begins to form.
- **Nuclear membrane disappearing**: The nuclear envelope breaks down during prophase in preparation for chromosome separation.

Therefore, based on these observations, the student is most likely observing **prophase**.