2 Cell Division For cells, bigger is not better As cells get bigger, volume increases faster than surface areaThis makes it difficult for the cell to take in enough nutrients and get rid wastes efficientlyWhen a cell reaches its max size, the nucleus initiates cell division
3 Results of Cell Division The cell cycle is important for:reproduction in some organismsasexual reproduction = identical offspringRegeneration (ex – sea star)BuddingFissiongrowth in multicellular organismsCell differentiationRepair replacement of worn out or damaged cells, and repair of damaged tissues.Lesson 1
4 The Cell Cycle (cont.)Most cells in an organism go through a cycle of growth, development, and division called the cell cycle.There are two main phases in the cell cycle—interphase and the mitotic phase.
5 Part 1 -InterphaseInterphase occurs in three stages: G1, S, and G2, and takes up 90% of the time of the cell cycleG1 (gap 1)Period of growth, DNA = chromatinS (synthesis)Chromosomes replicateLesson 1
6 Part 1-Interphase G2 (gap 2) Cell creates organelles The cell’s DNA is copied during the S stage and is arranged as pairs of identical chromosomes called sister chromatids.Sister chromatids are held together by a structure called the centromere.G2 (gap 2) Cell creates organellesLesson 1
7 The Mitotic PhaseDuring mitosis, the contents of the nucleus divide, forming two identical nuclei.Lesson 1
20 ReviewIn order, name the 5 stages of the cell cycle.During which interphase stage do organelles replicate?What do you call the division of the cell’s cytoplasm ?During which interphase stage is DNA created?During which stage do spindle fibers form?During which stage are chromosomes aligned in the middle?During which stage are chromatids separated?During which stage does the nucleus dissolve?What is the result of mitosis?
21 In order, name the 5 stages of the cell cycle. Interphase, Prophase, Metaphase, Anaphase, TelophaseDuring which interphase stage do organelles replicate?G1What do you call the division of the cell’s cytoplasm?CytokinesesDuring which interphase stage is DNA created?SDuring which stage do spindle fibers form?ProphaseDuring which stage are chromosomes aligned in the middle?MetaphaseDuring which stage are chromatids separated?AnaphaseDuring which stage does the nucleus dissolve?What is the result of mitosis?2 identical (daughter) diploid cells