Transcript Chromosomes
Mitosis and Cell Division New Cells • About 2 trillion new cells each day. – About 25 million per second!! • Cell division is also called cell reproduction. - New Cells • The type of cell division depends on the type of cell. – Prokaryotes divide differently than eukaryotes. - Mitosis • Cells getting ready to divide. – Non-reproductive cells. • Takes place continuously. – Except nerve cells. - Stages of Mitosis Interphase • Most of the cell’s life cycle is spent in this phase. • Cell increases in size just before the next phase begins. - Stages of Mitosis Prophase • Mitosis begins. • All organelles divide so number doubles. • All DNA coils up into chromosomes. • Chromosomes copy themselves. - Chromosomes Chromatids centromere Sister chromatids chromatid Prophase Stages of Mitosis Metaphase • Chromosomes line up, break apart. – Each side contains all genetic information.- Metaphase Stages of Mitosis Anaphase • Broken halves of chromosome pulled to opposite sides of the cell. - Anaphase Stages of Mitosis Telophase • Nucleus re-forms. • Mitosis is complete. • Cell division almost done. - Telophase After Mitosis • Cytokinesis: Cytoplasm divides and you have two distinct daughter cells. - Cytokinesis Interphase Inside nucleus Then, tightly into chromosomes. DNA iscoils in long strands in the nucleus Prophase Inside Cell nucleus centromere Chromosome Replicated Chromosome Metaphase Inside Cell Cell Equator Anaphase Spindle fibers Centriole Telophase Cytokinesis