• all contents of the cell have to be duplicated-all DNA RNA, proteins, and organelles (in eukaryotes)
• The copies of DNA must divide evenly between the two daughter cells

• in single celled organisms, it is their mean of reproduction for future generations
• in multicellular organisms, cells it replaces damaged or lost cells or permits growth of the organisms

• a set of one maternal and one paternal chromosome that pair with each other in the cell during nuclear division
• are the same basic size and shape and carry the same genes int he same location
• NOT identical to one another though

• identical copies (chromatids) formed when DNA replicates during the cell cycle
• joined to one another at a sequence called centromere
• they have the exact same sequence as one another
• the centromeres are held together by a protein called kinetochore

the structure of DNA with the histones together

-beads on a string

1. Mitosis - nuclear division
2. Cytokinesis- cytoplasmic division

1. prophase
2. prometaphase
3. metaphase
4. anaphase
5. telophase

• chromosomes begin to condense
• Microtubules start to arrange into spindles
• the spindles move the chromosomes at the right time
• nuclear envelope starts to degrade

• chromosomes have entirely condensed
• nuclear envelope completely disintegrates so that there is no nucleus anymore
• spindles start attaching to the kinetochore of the chromosomes
• spindles are on opposite ends of the cell at the poles

• easiest to recognize
• the chromosomes align at the middle of the cell called the metaphase plate

• a very mobile phase
• spindles are shortening and pulling the sister chromatids to the opposite ends of the cell
• SISTER CHROMATIDS are what separate during this process
• the cell elongates as protein push the poles farther apart

• finishing stage
• one set of chromosomes reach each pole
• nuclear envelopes begin to form and nuclei reappear
• chromosomes relax into chromatin
• spindles begin to disappear
• true end of mitosis

• microfilaments form a ring around the center of the cell

What happens in cytokinesis

• the ring of microfilaments contracts more and more until the plasma membrane portions meet and fuse
• the cells pinch off from one another and form two daughter cells
• each daughter cell gets one nucleus and about half of the cytoplasm cell body
• each daughter cell enters interphase and the cycle starts all over again

a motor protein that walks along the spindles toward the pole, pulling the chromosomes with it.

As the proteins walk, the Spindels behind it disintegrates. 

the equator of the cell first vesicles form and eventually fuse to form a cell plate

- the plate then extends to become part of the outer cell wall

-stimulate cyclins and CDKs to pair up and the cell is told to progress through the cell cycle

-only happens in an environment when new cells are needed

G0- the resting phase

- it doesn't grow or divide, it just performs the functions of the cell

• no growth signals are received
• issue internally to the cell

• arrest of the cell
• or apoptosis (programmed cell death)

• lack of nutrients
• contact inhibition- cells touching neighboring cells
• if the cell is not anchored
• DNA damage

a genetic disease leading to dysregulation of the cell cycle in somatic cells

• abnormal growth and division
• checkpoints are completely ignored
• evade programmed cell death

are abnormal growths of cells

- they are masses that just keep growing and growing

• multicellular masses that aren't truly cancerous
• tend to just stay in one spot
• don't invade surrounded tissues or cause damage to surrounding tissues

• cancerous cells
• rapidly growing
• invade and damage surround tissues
• have ability to spread to other parts of the body

• tumor suppressor genes
• and proto-oncogenes

tell the cycle to halt

-like breaks on a car

can casue cell cycle arrest of apoptosis

p53

-mutated in roughly 50% of cancers

normally supposed to sense DNA damage and induce apoptosis

instruct the cell cycle to progress

- would be the gas in the car

when they malfunction the name changes to oncogenes

cyclin/CDK pairs

- they're growth factors that encourage cell growth and division

- it is bad when it becomes deregulated

• prokaryotic cell division
  • single chromosome replications
  • replication start at specific sequences called the Origin of Replication
  • the presence of more than One Origin triggers the cell to start dividing
  • chromosomes move apart to opposite ends of the cell
  • plasma membrane pinches inward, dividing the cell in two