Chp. 11 - Cell Cycle

Cancer

mitosis and meiosis

produces gametes

Produces haploid daughter cells

Basis of sexual reproduction

Produces daughter cells that are identical to parent cells

Produces Somatic cells (Body Cells)

the division of the cytoplasm into two daughter cells

Growth

Wound Repair

Cellular Respiration

DNA

Genetic Information

Mitotic phase and Interphase

Dividing phase

Non-dividing phase

-replication - chromosomes are copied

-splitting copied chromosomes into daughter cells

Synthesis phase

The stage where DNA replication occurs

2 phases where no DNA synthesis occurs

Organelles replicate and additional cytoplasm is made

G1 phase

S phase

G2 phase

Mitosis

each of two replicated strands

Interphase

Chromosomes replicate and are now composed of 2 sister chromatids

chromosomes condense

mitotic spindles begin to form from microtubule organizing center

nuclear envelope breaks down

spindle fibers attach to chromosomes at kinteochore

chromosomes are lined up in the middle of the cell

Sister Chromatids seperate and are pulled to opposite poles

nuclear envelope reforms

spindle apparatus is disintegrates

chromosomes begin to decondense

Actin-Myosin ring causes plasma membrane to pinch in a cleavage furrow forming 2 daughter cells

vesicles are transported from golgi apparatus to middle of dividing cell to form cell plate.

deattach-move-attach cycle of motor proteins allow chromosomes to walk

Tubulin subunits within the kinetochore are lost therefore shorteining microtubules

when non-dividing cells get stuck in G1 phase.

rapidly dividing cells

Mitosis promoting factor (MPF)

Cytoplasm of M phase cells

Cyclin and protein kinases

regulatory protein

catalyze the transfer of phosphate from ATP to protein

phosphorylate chromosomal proteins, start M phase

phosphorylate nuclear lamins, start nuclear envelope breakdown

phosphorylate microtubule associated proteins, activate mitotic spindle

phosphorylate enzymes that degrades cyclin, cyclin concentration declines

Point in cell-cycle where regulatory molecules determine if a cell proceeds with cell division

G1

G2

Metaphase

Determines whether cells continue to divide or enter G₀ phase

-cell size - cell must be large enough to split

-nutrient condition - cell must have enough food to grow

-cell must be able to receive social signals from other cells

-action of tumor suppressors - regulatory proteins that can stop cell cycle

G1 checkpoint

to stop cells from growing if their DNA is damaged or chromosome replication is not working properly

To stop cell growth if chromosomes are not properly attached to mitotic spindle

incorrect chromosome seperation that could give daughter cells the wrong number of chromosomes

To prevent the division of cells that are damaged or have other problems.

uncontrollable cell growth that invades nearby cell tissues and spreads to other sites in the body

-proteins required for cell growth are always active

-tumore supressor genes are prevented from shutting down the cell cycle

when one or more cells in an organism divide uncontrollably

noninvasive and noncancerous tumors

invasive tumors that can spread throughout the body and initiate secondary tumors

when cancer cells detach from the original tumor and invade other tissues

G1 checkpoint

cells respond to signals of other cells so they only divide when their growth benefits the whole organism

Polypeptides or small portiens that signal other cells to grow

Cancer cells divide without Growth Factors

they trigger cyclin synthesis which activates cyclin-Cdk complexes, leading to activation of S-phase proteins

cell-cycle regulation