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Why do cells Divide? For  Growth  Development  Repair  Reproduction Larger cells: - can miscommunication with DNA - have trouble processing information.

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Presentation on theme: "Why do cells Divide? For  Growth  Development  Repair  Reproduction Larger cells: - can miscommunication with DNA - have trouble processing information."— Presentation transcript:

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2 Why do cells Divide? For  Growth  Development  Repair  Reproduction Larger cells: - can miscommunication with DNA - have trouble processing information - struggle to exchange materials across the membrane (SA:V)

3 Cell Division Two Types of reproduction Asexual Reproduction ○ Genetically identical offspring from a single parent’s cells dividing Sexual Reproduction ○ Fusion of sex cells from 2 individuals

4 Advantages of Reproduction Types  Asexual: Survival Strategy for single celled organisms Offspring are genetically identical to parent. Occurs rapidly under favorable conditions. Lower energy input  Sexual: Survival Strategy for multi-cellular organisms Offspring are genetically varied from parent An advantage in environments that change frequently Higher energy input

5 Cell Division A single cell divides into 2 daughter cells

6 The Cell Cycle A Series of steps a cell goes through  Growth of the cell / parts  Synthesis of new DNA  Division of the cell

7 Cell Division The Beginning of the Cycle is called Interphase  G 1 - intense growth and making of new proteins and organelles  S - new DNA is synthesized so 2 copies of the chromosomes exist  G 2 – Preparation and replicating organelles

8 The Cell Cycle A Series of steps a cell goes through: -growth, preparation, division B. Prokaryotes: - asexual reproduction called binary fission C. Eukaryotes - Four phases: G 1, S, G 2, and M

9 The Cell Cycle The Second Stage in the cycle is Mitosis (division of nucleus and cytoplasm)

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11 III. Chromosomes A. Packages of DNA (genetic information) that is bundled together. centromere chromatids Duplicated chromosome

12 Chromosomes (cont.) B. Prokaryotes -Contain single, circular chromosome. Bacterial chromosome plasmids

13 Chromosomes (cont) C. Eukaryotes -contain multiple chromosomes -Chromatin -DNA is generally wrapped around proteins called histones.

14 Counting Chromosomes  Chromosomes can have one or two sets of DNA.  Count chromosomes by counting the number of centromeres

15 a. Mitosis Prophase – 1. genetic material condenses 2. chromosomes become visible 3. spindle starts to form 4. nuclear envelope disappears

16 Mitosis (cont.) Metaphase – 1. Duplicated chromosomes line up in middle 2. Spindle fibers connect to centromeres

17 Mitosis (cont) Anaphase – 1. Sister chromatids separate and move to opposite ends of the cell

18 Mitosis (cont) Telophase 1. Condensed chromosomes begin to spread out into chromatin. 2. Nuclear envelope re-forms

19 b. Cytokinesis -division of the cytoplasm -splits parent cell into identical 2 daughter cells

20 Cytokinesis (cont) Animal Cells: membrane pinches inward Plant Cells: cell plate develops from inside

21 Cell Division Animation  http://highered.mcgraw- hill.com/sites/0072495855/student_view 0/chapter2/animation__how_the_cell_cy cle_works.html http://highered.mcgraw- hill.com/sites/0072495855/student_view 0/chapter2/animation__how_the_cell_cy cle_works.html


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