Cellular Reproduction Mitosis & Meiosis Notes

3-Step Process DNA Replication Nuclear Division Cellular Division

DNA Replication DNA unzips and complementary strands are built Template Takes place during Interphase Between cell divisions Time of cell growth and protein synthesis Majority of time

Nuclear Division MITOSIS

Mitosis Body Cells – Somatic Cells Process by which the nucleus divides Produces two identical nuclei

Prophase 1st phase Centrioles move to opposite poles Spindle fibers form Chromosomes condense / visible Nuclear membrane disappears

Metaphase Chromatids line up at the equator

Anaphase Chromosomes pull apart Move toward opposite poles

Telophase Last phase Nuclear division Nuclear membrane forms around each new nucleus Chromosomes become invisible

Cell Division Cytokinesis

Cytokinesis Division of cell’s cytoplasm and organelles Two separate cells Result is two diploid daughter cells identical to parent cell

Cytokinesis: Animal Cell Microfilaments contract Pinches in at equator to form cleavage furrow

Cytokinesis: Plant Cell Cell wall formation between new cells Cell Plate Vesicles congregate

Cell Division Meiosis

Meiosis Sex cells – gametes Germ cells in ovaries and testes Sperm Egg Germ cells in ovaries and testes Diploid cell produces haploid cells Gametes Involves two cell divisions

Process similar to mitosis: First Cell Division Interphase – DNA replicated Prophase I Tetrads form (4) Crossing over (genetic material exchange) Metaphase I Tetrads line up (pairs) Anaphase I Telophase I Cytokinesis

Second Cell Division Interphase – NO DNA replication Prophase II Metaphase II Anaphase II Telophase II Cytokinesis

Meiosis Result is 4 haploid daughter cells Gametes Gametes can combine to form a diploid cell with chromosomes from each parent Like YOU!

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