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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 nextOrFrom cell “birth” to cell “death”Alternation between Interphase and Mitosis
A look at the cell cycle
G1
S
G2
M
G1 S G2 M
Components
Interphase (G1, S, G2) and Mitosis (M)Gap 1: birth to DNA replicationSynthesis: DNA duplicationGap 2: gap before mitosisMitosis: nuclear division (followed by cytokinesis)
Mitosis: The steps
Prophase
Prometaphase*
Metaphase
Anaphase
Telophase
Cytokinesis*
*extensions from the “PMAT” skeleton of mitosis
Prophase
Chromatin condenses into ChromosomesSister chromatids attached at centromereNuclear envelope still present
PrometaphaseNuclear 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 SynthesisCentromere: condensed region of a chromosomeKinetochore: 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
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