1 Ch 9 The Cellular Basis of Life 9.1 Cells come from Cells Cells are needed for Mitosis: repair, growth, asexual reproduction (clones of one parent) Meiosis: sexual reproduction (two parents) VVVV iiii dddd eeee oooo c c c c llll iiii pppp ( ( ( ( (3 minute overview of mitosis/cancer)

2 9.2 The cell cycle multiplies cells Different number of chromosomes for each organism (humans have 46) Interphase: Chromosomes duplicate before the cell divides

3 Mitosis- nucleus divided  and Cytokinesis-cell divides

4 9.3 Mitosis Prophase=pairs Metaphase=middle Anaphase=away Telophase=two Cytokinesis animals Cell plate plants Onion root tip Onion root tip

5 9.4 Cancer  Cancer is due to uncontrolled cell cycle  Benign –local tumor  Malignant- travels around body by metastasis  Treatment=surgery, radiation, chemotherapy (some disrupt mitotic spindle)

6 9.5 Meiosis is used in sexual reproduction Meiosis only occurs in sperm and egg so the new offspring doesn’t have double the chromosome number Diploid Haploid Chick embryo Pig embryo Human embryo

7 Meiosis- two divisions Results in four cells

8 9.6 Meiosis increases genetic variation

9 Crossing over In Meiosis In Meiosis