Mitosis Post-Lab Quiz: OnRamps Bio

Interphase

Chromatin undergoes DNA replication during normal cell growth.

Prophase

The chromatin condenses into chromosomes. The nuclear envelope dissolves.

Metaphase

Chromosomes line up in the middle of the cell held in position by the mitotic spindle.

Anaphase

Chromosomes are split in half at the centromere and separated into two chromatids. The chromatids are pulled to separate ends of the cell.

Telophase

Cleavage furrow forms and cytoplasm starts to pinch in half. Two complete nuclei are formed.

Cytokinesis

Cytoplasm splits, new cell membranes are formed.

Where is the specific site of mitosis in plant roots?

The Meristem (specifically the Zone of Cell Division).

Why is the Onion Root Tip used to study mitosis?

It contains a meristematic region where cells are actively and rapidly dividing.

Why is the Whitefish Blastula used to study mitosis in animals?

It is an embryonic stage where cell division is at its highest rate before cells begin to differentiate.

What is the function of the Root Cap?

It is a layer of cells that protects the meristem as the root pushes through the soil.

How do you calculate the Proportion of Cells in a specific phase?

{Number of cells in phase} / {Total number of cells counted}

If a cell cycle takes 24 hours (1,440 mins), how do you find the Time in Stage?

{Number of cells in phase / Total number of cells counted} x 1,440 minutes

What does a high proportion of cells in a specific phase indicate about that phase?

It indicates that the phase has a longer duration (the cell spends more time in that stage).

In which stage of the plant cell cycle do you see a cell plate forming?

Telophase/Cytokinesis (The cell plate eventually becomes the new cell wall).

What happens to the Nuclear Envelope during Prophase?

It disappears so that the spindle fibers can reach the condensed chromosomes.

Why should you survey three different regions on a slide instead of just one?

To ensure a representative sample, reduce bias, and get a more accurate average estimate.

Even in a fast-growing meristem, which phase will likely have the highest count?

Interphase. (DNA replication and preparation take significantly longer than the physical stages of mitosis).