Intro to topic 3

Notes

There are 2 reasons cells divide rather than grow indefinitely. 1. The larger that cells become, the more demand the cell places on the DNA

2. the large the cell becomes the more trouble the cell has moving enough nutrients and wastes across the cell membrane

Cell division is

The process of DNA replication and the division of the cytoplasm to form 2 new identical cells

Cell division reduces the volume, and increases the ratio between volume and surface area.

you will need to be able to calculate surface area, volume and the ratio of surface area to volume

http://www.youtube.com/watch?v=pv_-RWaADwk&feature=related&safety_mode=true&persist_safety_mode=1&safe=active

Hw: Do Worksheet on cell growth

Cell DivisionChromosomes are not visible in most cells, except during ________________Cell division

When chromosomes become visible they consist of ________________________________________________________

2 sister chromatids connected at the centromere

Each pair of chromatids is attached at an area called the ___________________________centromere

The Cell Cycle is diagramed below:

The period of growth between cell divisions is called ______________________________

Interphase

The division of the nucleus during the M phase of the cell cycle is called ___________________.Mitosis

Interphase is divided into 3 phases_____________________________________________________________

G1 PhaseS Phase

G2 Phase

During the G1 phase ________________________

During the S phase ___________________

During the G2 phase _________________________

Rapid growth

Replication of Chromatids

Prep for mitosis (make another centriole)_

HW: DO CELL CYCLE WORKSHEET

The 4 phases of Mitosis are:

1. Prophase -- Chromosomes become visible, nucleus and nucleolus dissolve. Centrioles move to opposite ends and form microtubules( spindle).

Centrioles Microtubles/ spindle

Chromosomes

2. Metaphase -- Chromosomes line up across the middle of the cell

Chromosomes Centrioles

Microtubles/ spindle

3. Anaphase -- Chromosomes migrate

to the 2 ends of the cell

4. Telophase -- New nuclear membrane forms, and the cell begins to divide by cytokinesis.

centrioles

chromatids

chromosomes

Two new daughter cells

Interphase

prophase Metaphase

anaphase

telophase

centriolespindle

chromosomes

Cell membranenucleoluscentrioles

chromosomesNuclear membrane

In animal cells _______________________ located near the nucleus help separate the chromosomes by forming ________________________.

_____________________ is the process of the cytoplasm being divided in two pieces.

In pant cells a _____________________ forms midway of the cell.

Centrioles

Spindle fibers

cytokinesis

Cell plate

When an injury occurs the cells in the area begin to ____________________

When the injury is almost healed __________________________

__________________ are responsible for regulating the cell cycle.

the rate of cell division slows

divide

cyclins

Cancer is _________________________________________Cancer cells don’t respond to signals that regulate ___________Cancer cells form masses of cells called ___________________Cancer cells break loose and spread throughout the ___________________

unregulated cell growth

tumors

body

growth

Hw: 21 in workbookworksheet