Source: Ashray Shah/Shutterstock Source: Ashray Shah/Shutterstock Source: Ashray Shah/Shutterstock Source: Ashray Shah/Shutterstock Diagramming Mitosis Copy the diagrams of the phases of mitosis into your notebook. Then label the components of the cell as it undergoes division. Thinking of what you learned in the unit, write a short sentence describing the process being illustrated in each diagram. Use your completed diagrams to answer the following questions: Why is it important that the nuclear membrane dissolve? What organelle is responsible for moving the sister chromatids within the cell? How do you know that the two daughter cells will be genetically identical to their parent? The diagrams show cell proliferation. How does this relate to differentiation? Review your completed diagrams and the answers to your questions. Decide whether you feel you are ready to move on or if you need to go back and review some lesson material before moving on.

Mitosis Diagram Overview

Phases of Mitosis:

1. Prophase

   • Chromatin condenses into visible chromosomes.
   • The nuclear membrane begins to dissolve.
   • Mitotic spindle fibers start to form.

2. Metaphase

   • Chromosomes line up along the metaphase plate (equatorial plane).
   • Spindle fibers attach to the centromeres of the chromosomes.

3. Anaphase

   • Sister chromatids are pulled apart toward opposite poles of the cell by spindle fibers.

4. Telophase

   • Chromosomes reach the poles and begin to de-condense back into chromatin.
   • The nuclear membrane reforms around each set of chromosomes.

5. Cytokinesis (not technically a phase of mitosis but often included in the discussion)

   • The cytoplasm divides, creating two daughter cells.

Descriptions of the Process

1. Prophase: The chromatin condenses into chromosomes, and the nuclear membrane dissolves, allowing the spindle apparatus to interact with the chromosomes.

2. Metaphase: Chromosomes line up in the center of the cell, ready to be separated, ensuring each new cell will receive the correct number of chromosomes.

3. Anaphase: The sister chromatids are pulled to opposite sides of the cell, ensuring each daughter cell gets an identical set of chromosomes.

4. Telophase: The newly separated chromosomes reach the poles, nuclear membranes reform, and the cell begins to prepare for division.

5. Cytokinesis: The cytoplasm divides, resulting in two genetically identical daughter cells.

Answering the Questions

1. Why is it important that the nuclear membrane dissolve?

   • The dissolution of the nuclear membrane is crucial because it allows the spindle fibers to access the chromosomes and facilitate their alignment and separation. Without this step, chromosome segregation could not occur properly.

2. What organelle is responsible for moving the sister chromatids within the cell?

   • The spindle apparatus, composed of microtubules produced by centrosomes, is responsible for moving the sister chromatids during mitosis.

3. How do you know that the two daughter cells will be genetically identical to their parent?

   • The daughter cells are genetically identical because mitosis is a process of cell division that replicates the genetic material accurately during the S phase of interphase, and the sister chromatids created during DNA replication are equally distributed during anaphase.

4. The diagrams show cell proliferation. How does this relate to differentiation?

   • While cell proliferation refers to the process of cell division and growth, differentiation is the process by which cells develop distinct functions and characteristics. After proliferation, many cells will undergo differentiation to perform specialized tasks in the organism, demonstrating how the initial identical daughters can eventually contribute to various tissue types.

Reflection

After reviewing the completed diagrams and answers, if you feel confident with your understanding of these processes, you may be ready to move on. However, if there are any uncertainties or concepts that require further review, it's advisable to revisit the lesson materials for clarification.