Anatomy Chapter 3 part 3

Cell Division:

is the division of nucleus, in which the duplicated DNA is disturbed to new daughter cells

• Mitosis

• Prophase

• Metaphase

• anaphase

• telophase

Cell Division:

Early _____

-chromatin condenses, forming visible chromosomes

-each chromosome and its duplicate (called sister chromatids) are held together by a centrosome

Centrosome and its duplicate begin synthesizing microtubules that push each centrosome to opposite poles of cell

• Mitosis

• Prophase

• Metaphase

• anaphase

• telophase

Cell Division:

Late_______

Nuclear envelope breaks up

• Mitosis

• Prophase

• Metaphase

• anaphase

• telophase

Cell Division:

Centromeres of chromosomes are precisely aligned at cells equator

the imaginary plane midway between poles is called metaphase plate

• Mitosis

• Prophase

• Metaphase

• anaphase

• telophase

Cell Division:

-Begins when chromosome movement stops

-each set of chromosomes (at opposite ends of cell) uncoils to form chromatin

-new nuclear membranes form around each chromatin mass

-nucleoli reappear

-spindle disappears

• Mitosis

• Prophase

• Metaphase

• anaphase

• telophase

Cell Division:

-begins during late anaphase and continues through mitosis

-ring of actin microfilaments contracts to form cleavage furrow

-two daughter cells are pinched apart

• cytokinesis

• Prophase

• Metaphase

• anaphase

• telophase

Control of Cell Division

"go" and "stop" signals direct when a cell should not divide

Go signal include:

when area of membrane becomes inadequate for exchange (when the volume gets too large)

• Critical surface to volume ratio of cell

• availability of space

Control of Cell Division

normal cells stop dividing when they come into contact with other cells

-referred to as contact inhibition

• Critical surface to volume ratio of cell

• availability of space

Control of Cell Division:

regulatory proteins that accumulate during interphase

• Cyclins

• Cyclin- dependent kinases

Control of Cell Division:

that activate cyclins when they bind to them

• Cyclins

• Cyclin- dependent kinases