Cell Size Surface Area (length x width x 6) Volume (length x width x height) Ratio of Surface Area to Volume Surface Area: Volume Ratio As Cells grow in size their SA/Vol ratio decreases and they become less able to feed themselves and get to a point where they must divide Go to Section:

Why Should I care about Mitosis? grow in size. heal wounds. stay healthy. Because I need to make new cells in order to…

The Life expectancy of three different cells

What does a new cell need? Nucleus - (DNA!!!) Organelles Cytoplasm Cell membrane

The Cell nucleus then DIVIDES during Mitosis All DNA and Organelles are copied during INTERPHASE The rest of the cytoplasm and organelles divide during Cytokinesis

After the DNA copies itself, it then coils up into CHROMOSOMES We can see these chromosomes during MITOSIS

Chromosomes – made of DNA + protein DNA: Instruction book with genetic information used to direct the cell. Protein: Holds DNA in coiled structure. Any Cell that has pairs of chromosomes is said to be DIPLOID Human cells contain 23 pairs of each type of chromosome in the nucleus (except egg and sperm cells). 23 (mom) + 23 (dad) = 46 total

1 pair of chromosomes: Homologous Chromosomes Paired copies of the same chromosome (mom + dad) Sister Chromatids These are chromosomes which have copied each other and are ready to divide

What is mitosis? Nuclear cell division where copied chromosomes are separated to form two identical nuclei. Phases: PROPHASE METAPHASE ANAPHASE TELOPHASE

includes is divided into Concept Map Section 10-2 Cell Cycle M phase (Mitosis) Interphase G 1 phaseS phaseProphaseG 2 phaseMetaphaseTelophaseAnaphase Go to Section: Cytokinesis

M phase G 2 phase S phase G 1 phase The Cell Cycle Section 10-2 Go to Section:

Phases of cell cycle: INTERPHASE G 1: Cell growth occurs. S: Chromosomes replicate. G 2: Organelles replicate MITOSIS M: Copied chromosomes are equally divided and new nuclei formed. CYTOKINESIS (cell divides)

Centrioles Chromatin Interphase Nuclear envelope Cytokinesis Nuclear envelope reforming Telophase Anaphase Individual chromosomes Metaphase Centriole Spindle Centriole Chromosomes (paired chromatids) Prophase Centromere Spindle forming Section 10-2 Interphase, Mitosis and Cytokinesis Go to Section:

Centrioles Chromatin Interphase Nuclear envelope Cytokinesis Nuclear envelope reforming Telophase Anaphase Individual chromosomes Metaphase Centriole Spindle Centriole Chromosomes (paired chromatids) Prophase Centromere Spindle forming Section 10-2 Interphase, Mitosis and Cytokinesis Go to Section:

Centrioles Chromatin Interphase Nuclear envelope Cytokinesis Nuclear envelope reforming Telophase Anaphase Individual chromosomes Metaphase Centriole Spindle Centriole Chromosomes (paired chromatids) Prophase Centromere Spindle forming Section 10-2 Interphase, Mitosis and Cytokinesis Go to Section:

Centrioles Chromatin Interphase Nuclear envelope Cytokinesis Nuclear envelope reforming Telophase Anaphase Individual chromosomes Metaphase Centriole Spindle Centriole Chromosomes (paired chromatids) Prophase Centromere Spindle forming Section 10-2 Interphase, Mitosis and Cytokinesis Go to Section:

Centrioles Chromatin Interphase Nuclear envelope Cytokinesis Nuclear envelope reforming Telophase Anaphase Individual chromosomes Metaphase Centriole Spindle Centriole Chromosomes (paired chromatids) Prophase Centromere Spindle forming Section 10-2 Interphase, Mitosis and Cytokinesis Go to Section:

Centrioles Chromatin Interphase Nuclear envelope Cytokinesis Nuclear envelope reforming Telophase Anaphase Individual chromosomes Metaphase Centriole Spindle Centriole Chromosomes (paired chromatids) Prophase Centromere Spindle forming Section 10-2 Interphase, Mitosis and Cytokinesis Go to Section:

HOW DOES MITOSIS KNOW WHEN TO STOP? Suppose you had a paper cut on your finger. Although the cut may have bled and stung a little, after a few days, it will have disappeared, and your finger would be as good as new. Section How do you think the body repairs an injury, such as a cut on a finger? 2. How long do you think this repair process continues? 3. What do you think causes the cells to stop the repair process? Go to Section:

Control of Cell Division Section 10-3 Go to Section: Cells will continue to grow UNTIL they touch another cell - this is called CONTACT INHIBITION

A sample of cytoplasm is removed from a cell in mitosis. A sample is injected into a second cell in G 2 of interphase. As a result, the second cell enters mitosis. Effect of Cyclins Section 10-3 Go to Section: Scientists discovered that a set of proteins they called “Cyclins” control the start of the cell cycle

Internal Regulators Internal Regulators - a series of proteins that make sure mitosis is controlled. Some make sure the cell does not enter mitosis until all chromosomes have been copied Others will not let the cell start anaphase until chromosomes are attached to the spindle

External Regulators Proteins that respond to events outside the cell They speed up or slow down the rate of cell division Growth factors tend to speed up rate of mitosis Molecules found on the surface of neighbouring cells tend to slow down rate so cells don’t interfere with each other