The Cell Cycle Interphase, Mitosis, and Cytokinesis 10-2

Learning Goals 1. Summarize the cell cycle and what it results in. 2. Describe the function of the cell cycle in both a unicellular and multicellular organism. 3. Define chromosome and describe its parts. 4. Describe what happens to the chromosomes in each of the 6 steps of the cell cycle.

Cell Cycle Cell Cycle - cell division that results in 2 new daughter cells that are an exact copy of the original (parent) cell.

The Cell Cycle Three Main Stages: a) Interphase (95%) b) Mitosis (5%) c) Cytokinesis M Phase M phase = cell division

Function Unicellular organisms reproduce this way (asexual reproduction) Multicellular organisms make new cells this way Causes organisms to grow To replace old worn out cells Repair damaged cells

Chromosomes Carry genetic information DNA = genetic code Every organism has a different # of chromosomes ex: humans have 46 (23 from mom & 23 from dad)

One chromosome = pair of sister chromatids Sister Chromatid = 1 copy of wound up DNA centromere Sister chromatids are held together by a centromere centromere Sister chromatid

Interphase occurs before mitosis begins Chromosomes, cytoplasm, and organelles are copied. The cell grows

Mitosis

Prophase 1st step in Mitosis The genetic material (DNA) condenses into bundles called chromosomes.

Nuclear membrane disappears Spindle fibers form Centrioles move to opposite sides of the cell

Metaphase 2 nd step in Mitosis The chromosomes line up along the middle of the cell

Spindle fibers attach to the centromeres of chromosomes

4.Anaphase 3 rd step in Mitosis Sister chromatids separate and move to opposite sides of the cell

Telophase 4 th step in Mitosis Nuclear membrane forms around each set of chromosomes

Chromosomes unwind into chromatin Spindle fibers disappear

Now you try! Identify the 4 steps of mitosis on the next slide ( Hint: They are not in order)

Metaphase Telophase Anaphase Prophase

Cytokinesis occurs after mitosis The cytoplasm splits in two Result is two identical cells that have the same number of chromosomes as the original cell.

REMEMBER! I Interphase P Prophase M Metaphase A Anaphase T Telophase C Cytokinesis IPMATC I Pray M ore At T he Church

Learning Goals 1. Summarize the cell cycle and what it results in. 2. Describe the function of the cell cycle in both a unicellular and multicellular organism. 3. Define chromosome and describe its parts. 4. Describe what happens to the chromosomes in each of the 6 steps of the cell cycle.