1. Cellular Reproduction
Mitosis
Cellular Reproduction

2. The Cell Cycle
Your cells are always doing something, which is what is described by the cell cycle.
Sometimes, they are growing, making proteins, doing chemical reactions, and maintaining homeostasis.
Other times, they are dividing to make more cells.
These are the 2 main parts of the cell cycle.

3. 2 parts of the Cell Cycle
During interphase, the cell grows and carries on normal cell functions. More than 95% of the time, this is what your cells are doing.
Once in while, your cells divide in half to make more cells. We call this mitosis.

4. Mitosis: key facts
The definition of mitosis is the period of time when the cell’s nucleus divides to create 2 identical daughter cells.

5. Mitosis: key facts
Mitosis only happens in body cells, which are called somatic cells (not reproductive cells).
Mitosis occurs in eukaryotes: plants, animals, and people.
Mitosis produces diploid cells (that have 23 pairs of chromosomes)

6. Mitosis: Key facts
1 cell divides in half to form 2 new cells, called daughter cells.
These cells are identical to the parent cells, and are called daughter cells.
Single celled eukaryotes can reproduce this way: asexually (all by themselves)

7. Interphase Interphase comes before mitosis.
During interphase, the cell makes a copy of its DNA, so that it is ready to divide.
Over 95% of the time, cells are in interphase.
Now, the cell is ready to divide in the 5 step process of mitosis!

8. Vocabulary preparation
A duplicated chromosome looks like the letter X and each half is called a “sister chromatid.”
The sister chromatids are held together in the center by the centromere.

9. Prophase: Phase 1 The longest phase of mitosis.
Chromosomes come together (condense) are become visible under the microscope.
The nuclear membrane begins to dissolve.

10. Metaphase: Phase 2 Chromosomes line up in the center of the cell.
Centromeres attach to spindle fibers which help them move around the cell.

11. Anaphase: 3rd phase
Sister chromatids begin to pull apart at the centromere.
Sister chromatids begin to move to the opposite sides of the cell.
Chromosomes don’t look like Xs anymore, now they are chromatids.

12. Telophase: Phase 4
In telophase, the now separated chromatids reach the opposite sides of the cell.
Chromosomes start to unwind, and you can’t see them under the microscope anymore.
The nuclear membrane re-forms. Now the cell has 2 brand new nuclei, and begins to separate into 2 cells.

13. Cytokinesis: after mitosis
Now the cell’s cytoplasm divides, so 2 new cells with 2 new nuclei are formed.
In animals, cells pinch apart along a seam called the cleavage furrow.
In plants, cells form a new cell wall in between the 2 nuclei called the cell plate.

14. Why do cells do mitosis?
There are many reasons why cells go through mitosis:
Reproduction in single celled eukaryotes
Helps us grow bigger and taller
Helps repair wounds
Helps fetuses turn cells into tissues into organs into organ systems (development)