Survey
* Your assessment is very important for improving the workof artificial intelligence, which forms the content of this project
* Your assessment is very important for improving the workof artificial intelligence, which forms the content of this project
Unit 11 Cell Division Cell Cycle • Interphase consists of G1, S and G2 phases • Cell spends about 90% of its time in interphase • Cell cycle consists of interphase and mitosis (division of nucleus) Interphase • G1 – Increased metabolic activity – Replication of organelles • S (synthesis) – DNA is duplicated – Each unduplicated chromosome becomes duplicated • G2 – Second growth phase – Preparation for division Chromosome structure • Duplicated chromosome – Duplicated during S phase of interphase • 2 sister chromatids joined by a centromere – Sister chromatids should be identical • Kinetochore on either side of centromere – Binds to microtubules during mitosis and directs the separation of sister chromatids Cytokinesis • Division of the cytoplasm • Occurs after mitosis Mitosis Ex. 11.1 • Answer questions • Watch video for help with answers Exercise 11.2 • Observe mitosis in whitefish blastula cells • Try to identify cells in each phase of mitosis. Exercise 11.3 • Observe mitosis in Allium (onion) cells. • Draw an example of each phase. • Compare mitosis in animal and plant cells. Meiosis • Purpose- production of gametes – Sperm and egg – Occurs in gonads • Meiosis occurs in animals and plants but is more complex in plants • Two cell divisions – Meiosis I – Meiosis II Homologous chromosomes • In a diploid cell, chromosomes exist in pairs that have corresponding but not identical genetic information. • One member of pair from mother, one from father. • Meiosis I – Separates homologous chromosomes • Meiosis II – Separates sister chromatids • At the end of Meiosis – 4 haploid gamete cells produced Exercise 11.5 • Simulate meiosis using pop-beads Cell Models • Pay attention to the cell models showing mitosis and meiosis which are displayed around the room. Unit 11 HW • Due next week • Reinforces concepts learned today