Transcript Cell Cycle
Cell Division • process by which cells reproduce themselves Chapter menu Resources Copyright © by Holt, Rinehart and Winston. All rights reserved. Cell Division in Prokaryotes • Binary fission • process where DNA is copied and cells are divided into two identical haploid cells Chapter menu Resources Copyright © by Holt, Rinehart and Winston. All rights reserved. Cell Division in Eukaryotes • Cell Cycle – the repeating set of events in the life of a cell – Regular pattern of growth, DNA duplication, and cell division Chapter menu Resources Copyright © by Holt, Rinehart and Winston. All rights reserved. Cell Division in Eukaryotes • Cell Cycle – 2 parts with 4 stages 1. Interphase (includes Stages 1, 2, 3) 2. M phase (includes Stage 4) – 4 Main Stages 1. Gap 1 (G1) 2. Synthesis (S) 3. Gap 2 (G2) 4. Mitosis and Cytokinesis (M) Chapter menu Resources Copyright © by Holt, Rinehart and Winston. All rights reserved. Cell Division in Eukaryotes 1. Interphase – consists of 3 Stages 1. (G1) = growth (increase in size) and increase number of organelles • Critical checkpoint before moving to Stage 2 2. (S) = DNA replication (copy DNA) 3. (G2) = more growth and preparation • Critical checkpoint before moving to Stage 4 Chapter menu Resources Copyright © by Holt, Rinehart and Winston. All rights reserved. Cell Division in Eukaryotes 2. M phase – consists of 1 Stage 4. (M) = 2 processes • Mitosis = division of the nucleus & DNA • Nuclear envelope disappears • DNA condenses and separates • 2 new nuclei form • Cytokinesis = division of cytoplasm Result is 2 identical cells Chapter menu Resources Copyright © by Holt, Rinehart and Winston. All rights reserved. Control of the Cell Cycle Chapter menu Resources Copyright © by Holt, Rinehart and Winston. All rights reserved. Rate of the Cell Cycle – In humans – S, G2, M = 12 hours – G1 = differs based on cell type Chapter menu Resources Copyright © by Holt, Rinehart and Winston. All rights reserved. Cell Size – If too small – Can’t hold all necessary organelles – If too large – Necessary materials cannot move across the cell membrane fast enough – Surface area to Volume ratio – too much volume, not enough surface area Chapter menu Resources Copyright © by Holt, Rinehart and Winston. All rights reserved.