Unit 3: Biology Date:________________

1.2 THE CELL CYCLE AND MITOSIS

WHY DO CELLS DIVIDE? When organisms _______ cells _______ (more cells) Why?

o So each cell stays ________, and ______________o To __________ old or ___________ cellso For ____________o For multicellular organisms to __________ (all cells require nutrients and must get

rid of waste)

CHROMOSOMES Structures found in the ____________ Made up of ________ (looks like a twisted ladder) DNA contains the _______ that provide the instructions for the cell Before division, a ______ of the DNA is made so each new cell has its own ______ Humans have ____ chromosomes

CHROMOSOME TERMINOLOGY CELL CYCLE

Unit 3: Biology Date:________________

MITOSISInterphase

Period _________ cell divisions _________ phase DNA ____________ preparation for _____________ ~ _______hr

Prophase ________ coil changing the long strands to ______and _______ chromosomes

Form a pair of _________, copied strands (chromatid) joined at the centromere

Nuclear __________ and ____________ disappear

_________separate and travel to opposite _________

(plant cells do not contain centrioles)

Metaphase

Chromosomes line up at ___________ (middle of cell) _______ _________ attach to ____________

Anaphase Sister ___________ are pulled to opposite poles ____________ divide in half

Telophase ________ ___________ are at opposite poles DNA becomes ________ again (chromatin) Nuclear membrane ____________

Cytokinesis Division of ______________ Animals: Cell membrane _________ in and forms two cells Plants: _______ _______ forms between the two daughter cells and will eventually

become a _____ _______

P M A T

UNCONTROLLED DIVISION: CANCER

Unit 3: Biology Date:________________

_________ _________ from the nucleus tell the cell when to _______, not to divide, or __________ itself.

Tumour: mass of cells that divide ______________. Mutation: permanent ________ in cell’s DNA which affect cells response to

__________ __________.

CANCER OR NOT?

Malignant (cancer) Benign

Cell divides uncontrollably (_____ _____) Cell divides uncontrollably (______ _______)

Damages and destroys ____________ _______ Does not interfere with neighbouring cell but can ______ them

Can spread to other parts of the body _____ ____ spread to other parts of the body

Interferes with the function of other cells, can result in death if not destroyed or removed

________ unless it becomes so large it interferes with ______

NORMAL VS CANCEROUS CELL DIVISION

Homework:

P g 14-19