Mitosis and The Cell Cycle reproducing cell after

Mitosis and The Cell Cycle reproducing cell after cell. .

Mitosis l The definition of mitosis is part of cellular division in which the nucleus divides l It occurs in somatic cells – Somatic cells (body cells) are all the cells that are not associated with gametes (sex cells).

The 4 Stages of Mitosis l In order, they are: – – – Prophase Metaphase Anaphase Telophase PMAT (Please Make Another Taco) There is a longer phase that takes place before mitosis—this phase is called interphase.

The 4 Stages of Mitosis l What happens during Prophase: – – Chromatin condenses into chromosomes Centrioles begin to separate Spindle fibers begin to form Nuclear membrane begins to break down

Prophase “Prepare”

The 4 Stages of Mitosis l What happens during Metaphase: – – The chromosomes line up in the middle of the cell Each chromosome is attached to a spindle fiber

Metaphase “Middle”

The 4 Stages of Mitosis l What happens during Anaphase: – – Chromosomes separate to form sister chromatids, they pull apart Sister chromatids begin to migrate to the poles of the cell

Anaphase “Apart”

The 4 Stages of Mitosis l What happens during Telophase: – – – Chromosomes gather at opposite ends of the cell They lose their distinct shape Spindle fibers disappear A new Nuclear Membrane begins to reform at each pole The cell is about to tear apart! (Peanut shape)

Telophase “Tear”

Cytokinesis l After the cell goes through mitosis, it is quickly followed by cytokinesis – – This is the division of the cytoplasm What actually makes 1 cell into 2 new cells The new cells are called daughter cells. Mitosis plus Cytokinesis make up the M phase of the cell cycle.

The Cell Cycle

Phases of the Cell Cycle l There are 4 phases to the Cell Cycle: – G 1 phase S phase G 2 phase M phase – Lets take a closer look at each stage. . – – –

G 1 Phase of Cell Cycle l G 1 phase is the beginning of Interphase. – – – It is characterized by cell growth The cell does the majority of its growth during this phase. Cells actually divide because they become too large to function at an optimal level. Becoming too large would cause a “DNA overload” l The cell’s DNA would no longer be able to serve the increasing needs of the growing cell

S Phase of the Cell Cycle l The S phase is characterized by DNA replication – Before the cell splits, it must make a copy of it’s DNA This is to ensure that both new daughter cells will have exact copies of that particular organism’s DNA – The S phase is the 2 nd part of Interphase –

G 2 Phase of the Cell Cycle l The G 2 phase is the last stage of Interphase. – – – It is characterized by the preparation for mitosis. Here the cell has grown to a maximum size, made a copy of it’s DNA Now the organelles needed for cellular division are produced as the cell prepares for mitosis

M phase of the Cell Cycle l The M phase is not a part of Interphase, it is classified under Cell Division – The cell first goes through the 4 stages of mitosis: l l - Prophase Metaphase Anaphase Telophase Cytokinesis takes place shortly after telophase and the cell division is complete and the cycle begins again. M phase includes all the steps of mitosis and cytokinesis.

Picture in book… l Can be found on page 245! l There will be a quiz on this exact picture coming up soon!

The End