Cell Reproduction  Prokaryotes Bacteria  Eukaryotes Plants & animals copyright cmassengale

Prokaryotes  Lack a nucleus  Have a single chromosome  Reproduce by binary fission  Include bacteria copyright cmassengale

Steps in Binary Fission  Used by bacteria  Cells increase their cell mass slightly  DNA & cell components are replicated  Each cell divides into 2 daughter cells copyright cmassengale

Binary Fission of Bacterial Cell copyright cmassengale

E. Coli Dividing by Binary Fission copyright cmassengale

Eukaryotes  Contain a nucleus & membrane bound organelles  Asexually reproduce cells by mitosis copyright cmassengale

Cell Cycle  Stages in growth & division  G1 Phase  S Phase  G2 Phase  M Phase  Cytokinesis copyright cmassengale

G1 Phase  First growth stage  Cell increases in size  Cell prepares to copy its DNA copyright cmassengale

Synthesis Phase  Copying of all of DNA’s instructions  Chromosomes duplicated copyright cmassengale

G2 Phase  Time between DNA synthesis & mitosis  Cell continues growing  Needed proteins produced copyright cmassengale

M Phase  Cell growth & protein production stop  Cell’s energy used to make 2 daughter cells  Called mitosis or karyokinesis (nuclear division) copyright cmassengale

Life Cycle of a Cell Mitosis is a cycle with no beginning or end. copyright cmassengale

Interphase – Resting Stage  Cells carrying on normal activities  Chromosomes aren’t visible  Cell metabolism is occurring  Occurs before mitosis copyright cmassengale

Interphase

Stages of Mitosis  Prophase  Metaphase  Anaphase  Telophase copyright cmassengale

Cells Undergoing Mitosis copyright cmassengale

Steps in Prophase  DNA coils tightly & becomes visible as chromosomes  Nuclear membrane disappears  Nuceolus disappears  Centrioles migrate to poles  Spindle begins to form copyright cmassengale

Prophase

Eukaryotic Chromosome copyright cmassengale

Human Chromosomes copyright cmassengale

Steps in Metaphase  Spindle fibers from centrioles attach to each chromosome  Cell preparing to separate its chromosomes  Cell aligns its chromosomes in the middle of the cell copyright cmassengale

Metaphase

Steps in Anaphase  Cell chromosomes are separated  Spindle fibers shorten so chromosomes pulled to ends of cell copyright cmassengale

Mitotic Spindle copyright cmassengale

Anaphase

Steps in Telophase  Separation of chromosomes completed  Cell Plate forms (plants)  Cleavage furrow forms(animals)  Nucleus & nucleolus reform  Chromosomes uncoil copyright cmassengale

Telophase Plant Animal copyright cmassengale

Cytokinesis  Occurs after chromosomes separate  Forms two, identical daughter cells copyright cmassengale

Cytokinesis Cell Plate Forming in Plant Cells copyright cmassengale

Centrioles Chromatin Interphase Nuclear envelope Cytokinesis Nuclear envelope reforming Telophase Anaphase Individual chromosomes Metaphase Centriole Spindle Centriole Chromosomes (paired chromatids) Prophase Centromere Spindle forming Prophase (PREPARE)

Centrioles Chromatin Interphase Nuclear envelope Cytokinesis Nuclear envelope reforming Telophase Anaphase Individual chromosomes Metaphase Centriole Spindle Centriole Chromosomes (paired chromatids) Prophase Centromere Spindle forming Metaphase (MIDDLE)

Centrioles Chromatin Interphase Nuclear envelope Cytokinesis Nuclear envelope reforming Telophase Anaphase Individual chromosomes Metaphase Centriole Spindle Centriole Chromosomes (paired chromatids) Prophase Centromere Spindle forming Anaphase (AWAY)

Centrioles Chromatin Interphase Nuclear envelope Cytokinesis Nuclear envelope reforming Telophase Anaphase Individual chromosomes Metaphase Centriole Spindle Centriole Chromosomes (paired chromatids) Prophase Centromere Spindle forming Telophase (TWO)

Centrioles Chromatin Interphase Nuclear envelope Cytokinesis Nuclear envelope reforming Telophase Anaphase Individual chromosomes Metaphase Centriole Spindle Centriole Chromosomes (paired chromatids) Prophase Centromere Spindle forming Cytokinesis (TWO IDENTICAL DAUGHTER CELLS)

Let’s Review…

IV. Cell Specialization

A. Cells in Unicellular Organisms… 1. One cell makes up entire organisms. No cell specialization.

B. Cells in Multicellular Organisms… 1. Cell Specialization All of an organism’s cells have the same DNA Different cells use different genes to perform different functions Why do prokaryotes NOT have cell specialization?

Cells in Multicellular Organisms… Cell Specialization Examples: Blood cells carry oxygen Muscle cells control movement Nerve cells used for response