Cell Growth and Division Chapter 10

Why do cells divide? Cells divide to allow the organism to grow and to repair damaged tissue Cells grow, then divide. Why don’t they keep growing? Large cells do not have enough DNA to function. Large cells could not diffuse oxygen and nutrients efficiently. *Agar block lab*

Cell division in Prokaryotes and Eukaryotes: Prokaryotes – single chromosome is copied and the cell splits. Eukaryotes – All chromosomes must be copied into sister chromatids, held together by a centromere. The copies are then split apart in a process called MITOSIS. The cytoplasm is then split by CYTOKINESIS.

The Cell Cycle Cell cycle

Main steps of mitosis: “IPMAT” Interphase – The cells grows and replicates DNA and centrioles. Prophase – DNA wraps up into chromosomes. The nuclear membrane dissolves. Metaphase – Chromosomes line up. Spindle fibers created by the centrioles attach to the centromere.. Anaphase – The spindle fibers will pull the sister chromatids apart Telophase – chromosomes at opposite ends, the nuclear membrane re-forms.

Live video of mitosis: Cell division Newt cell division

Extra Credit Opportunity… Create cell models showing all 5 stages of mitosis (IPMAT) and cytokinesis. Cells must have (where applicable) and labeled: At least 2 chromosomes Spindle fibers Centrioles Centromeres Nuclear membrane

Mitosis Lab Microscope Images Onion Root tip Low Power

Onion Root tip – High Power

Whitefish blastula – Low Power

Whitefish blastula – High Power What phase is this cell in?

Duration of mitosis phases…