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The Cell Cycle. A Review. What is the Cell Cycle?. The time and activities that take place from one cell division to the next Or From cell “birth” to cell “death” Alternation between Interphase and Mitosis. A look at the cell cycle. Components. Interphase (G1, S, G2) and Mitosis (M)
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The Cell Cycle A Review
What is the Cell Cycle? • The time and activities that take place from one cell division to the next • Or • From cell “birth” to cell “death” • Alternation between Interphase and Mitosis
Components • Interphase (G1, S, G2) and Mitosis (M) • Gap 1: birth to DNA replication • Synthesis: DNA duplication • Gap 2: gap before mitosis • Mitosis: nuclear division (followed by cytokinesis)
Mitosis: The steps • Prophase • Prometaphase* • Metaphase • Anaphase • Telophase • Cytokinesis* *extensions from the “PMAT” skeleton of mitosis
Prophase • Chromatincondenses into Chromosomes • Sister chromatids attached at centromere • Nuclear envelope still present
Prometaphase • Nuclear envelope disappears • Sister chromatids clearly visible and attach to spindle via kinetochore
Metaphase • Chromosomes align at metaphase plate • Homologous pairs align SEPARATELY
Anaphase • Sister chromatids sever at centromere • V-shaped chromatids • Movement toward opposite poles
Telophase • Two visible sets of chromosomes • Nuclear envelope reforms
Cytokinesis • Cell division: cytoplasm divides • Formation of new cell membrane • Cytokinesis vs. Interphase: • Chromosomes still visible
Textbook Reference Materials • Chapter 4 second Edition • Title: The Chromosome Theory of Inheritance
Glossary • Chromatin: undifferentiated mass of thread-like DNA/protein in cell nucleus during interphase • Chromosomes: self-replicating structures in cells; contains DNA; visible during Prophase of mitosis
Glossary cont. • Sister chromatids: duplicated IDENTICAL chromosomes attached at centromere after Synthesis • Centromere: condensed region of a chromosome • Kinetochore: protein structure at centromere that acts as molecular “motor for chromatids
Glossary Cont. • Metaphase plate: imaginary equatorial line midway between cell poles
Selected Web Sites http://www.cellsalive.com/ cell cycle mitosis http://www.biology.arizona.edu/cell_bio/tutorials/cell_cycle/problems.html test yourself