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Chapter 12: The Cell Cycle
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What you must know: The structure of the duplicated chromosome.
The cell cycle and stages of mitosis. The role of kinases and cyclin in the regulation of the cell cycle.
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Cell Cycle: life of a cell from its formation until it divides
Functions of Cell Division:
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Genome = all of a cell’s genetic info (DNA)
Prokaryote: single, ______________ chromosome Eukaryote: more than one _______ chromosomes Eg. Human:46 chromosomes, mouse: 40, fruit fly: 8
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Each chromosome must be duplicated before cell division
Duplicated chromosome = 2 __________________ attached by a _____________
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Somatic Cells vs. Gametes
_________ (2n): 2 of each type of chromosome Divide by _________ Humans: 2n = 46 _____ cells (sperm/egg) _________ (n): 1 of each type of chromosome Divide by __________ Humans: n = 23
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Phases of the Cell Cycle
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Phases of the Cell Cycle
The mitotic phase alternates with interphase: G1 S G2 mitosis cytokinesis Interphase (90% of cell cycle) G1 Phase: cell _________ and carries out normal functions S Phase: _________________ chromosomes G2 Phase: prepares for ____________________ M Phase (mitotic) Mitosis: ______________ divides Cytokinesis: __________________ divides
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Mitosis: Prophase Metaphase Anaphase Telophase
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Mitosis Continuous process with observable structural features:
Chromosomes become visible (______________) Alignment at the equator (_______________) Separation of sister chromatids (_____________) Form two daughter cells (__________ & _________)
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Prophase & Prometaphase
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Metaphase & Anaphase
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Cytokinesis Cytoplasm of cell divided Animal Cells: ____________ Plant Cells: ____________ forms
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Cytokinesis in animal vs. plant cells
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Animal Cell Division
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Plant Cell Division
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Which phases of the cell cycle can you identify?
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Bacterial cells divide by:
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Cell Cycle Control System
Checkpoint = control point where stop/go signals regulate the cell cycle
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Major Checkpoints G1 checkpoint (Most important!) G2 checkpoint
Controlled by cell _____, _______ factors, environment “Go” completes whole cell cycle “Stop” cell enters nondividing state (G0 Phase) Nerve, muscle cells stay at G0; liver cells called back from G0 G2 checkpoint Controlled by ______________________completion, DNA ________________, cell size M-spindle (Metaphase) checkpoint Check spindle fiber (microtubule) attachment to chromosomes at __________________ (anchor sites)
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G1 Checkpoint
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M-spindle Checkpoint: Mitotic spindle at metaphase
_______________ = proteins associated with DNA at centromere
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Internal Regulatory Molecules
_________ (cyclin-dependent kinase, Cdk): protein ____________ controls cell cycle; active when connected to ___________ Cyclins: proteins which attach to kinases to ___________ them; levels fluctuate in the cell cycle
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Internal Regulatory Molecules
MPF = maturation-promoting factor specific ______________________ complex which allows cells to pass G2 and go to M phase
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External Regulatory Factors
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External Regulatory Factors
Growth Factor: ______________ released by ____________ cells to stimulate cell division _______________________ Inhibition: crowded cells normally stop dividing; cell- surface protein binds to adjoining cell to inhibit growth ___________________ Dependence: cells must be attached to another cell or ECM to divide
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Cancer Cells Cancer: disorder in which cells lose the ability to control growth by _________________________to regulation. multistep process of about 5-7 genetic changes (for a human) for a cell to transform loses anchorage dependency and density-dependency regulation Normal Cells Cancer Cells
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Tumors = mass of abnormal cells
___________ tumor: lump of cells remain at original site _________________ tumor: invasive - impairs functions of 1+ organs (called cancer) ___________________: cells separate from tumor and travel to other parts of body
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Cancer Prevention Anyone can get cancer but there are ways to minimize risk: Don’t smoke, legal or illegal (includes hookahs, chew, 2nd- hand smoke) Use sun protection Exercise and keep weight at ideal level Eat 5-7 servings of fruit and veggies a day Use screening/preventative measures-breast/testicle/mole checks Practice abstinence or use condoms Vaccines (eg. HPV)
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