The Cell cycle & Cell division: Mitosis

How the cell in the body replicate

Cell Life Cycle

Each cell has a life cycle The cell grows When it gets too big it prepares to divide When the cell divides it’s genetic material it is called Mitosis When the cells split it is called cytokinesis

InterphaseInterphase

This is the longest part of the cell’s cycle G1 phase – growth

S phase – DNA replication Chromatids are formed

G2 phase- prepare for Mitosis

Cell DivisionCell Division

• All cells come All cells come from existing from existing cells. All living cells. All living things create things create new cells by new cells by dividing. dividing.

• Cell division is Cell division is different in different in prokaryotes and prokaryotes and eukaryotes.eukaryotes.

Prokaryotic cell Prokaryotic cell reproducingreproducing

Cell Division in ProkaryotesCell Division in Prokaryotes

• Prokaryotes Prokaryotes reproduce by reproduce by binary binary fissionfission. .

• Steps in prokaryote Steps in prokaryote binary fission.binary fission.– DNA replicatesDNA replicates– Cell growsCell grows– New cell wall New cell wall

developsdevelops– Cell splits into two Cell splits into two

cellscells

Binary FissionBinary Fission

Cell division in Eukaryotic cells

DNA the nucleus divides before the rest of the cell does.The process of nuclear division is called mitosis. Mitosis is a multi step process.

Mitosis After the DNA is replicated inside the nucleus the chromosomes condense. Then the nuclear envelope dissolves. Chromosomes are lined up as sister chromatids in the center of the cell.

Mitosis continued

The chromatids separate into individual chromosomes Then they are moved apart to opposite sides of the cell.

Cytokinesis Each side of the cell has identical sets of the chromosomes So when the cytoplasm pinches apart during cytokinesis each daughter cell will have a complete copy of the DNA

Control of cell Division• The cell has checkpoints to insure cell division goes well.

– G1 checkpoint: if the cell is large and health it will divide

– G2 checkpoint: checks that the DNA was copies correctly

– Mitosis checkpoint: to make sure genetic material was divided correctly.

CancerIf one of the proteins that monitors cell growth is not working properly (usually because of a mutation in the genetic code) then the cell will divide uncontrollably. This is cancer.

Write a one paragraph summary summary of the cell cycle and cell division, explain why these

are important and what happens if something goes wrong.