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cell cycle and mitosis
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- 1the cell cycle-M phase
-interphase: G1, S and G2 phases - 2G1 checkpoint-1st and most important
-4 factors affect whether cells pass G1
-cell size, nutrient availability, social signals from other cells, and health of DNA - 3G2 phase-2nd checkpoint between G2 and M phases
-cells stop growing if chromosome replication has not proceeded properly or DNA is damaged - 4M (Metaphase) checkpoint-3rd and final checkpoint
-cell growth ceases during M phase if the chromosomes are not properly attached to the mitotic spindle
-M phase prevents incorrect chromosome separation - 5G0 phase-Non-Dividing Phase. Extended, non-dividing stage in cells that divide infrequently.
-If cells do not pass G1, they permanently stay that was in the G0 phase - 65 stages of mitosis-prophase
-prometaphase
-metaphase
-anaphase
-telophase - 7prophase-chromosomes condense
-first become visible under light microscope
-mitotic spindle - 8mitotic spindle in prophase-made up of microtubules (spindle fibers)
-forms microtubule organizing center
-Polar microtubules push the poles of the cell away from each other during mitosis
-Kinetochore microtubules pull chromosomes to the poles of the cell during mitosis - 9Polar microtubules (prophase)push the poles of the cell away from each other during mitosis
- 10kinetochore microtubules (prophase)pull chromosomes to the poles of the cell during mitosis
- 11prometaphase-nuclear envelope breaks down
-nucleolus disappears
-Kinetochore microtubules from each mitotic spindle attach to one of the sister chromatids of each chromosome
-Attachment occurs in the centromere region at the kinetochore - 12metaphase-formation of mitotic spindle is completed
-Motor proteins on the kinetochore microtubules pull each chromosome in opposite directions, causing the chromosomes to line up in the middle of the cell
-The imaginary plane formed by metaphase is called the metaphase plate - 13anaphase-centromeres split
-sister chromatids are pulled by the spindle fibers toward opposite poles of the cell
-replicated chromosomes split into two identical sets of unreplicated chromosomes
-as soon as they are no longer attached at the centromere, sister chromatids become daughter chromosomes
-motor proteins of the polar microtubules push the two poles of the cell away from each other - 14telophase-a new nuclear envelope begins to form around each set of chromosomes
-the mitotic spindle disintegrates
-chromosomes begin to decondense - 15mitosis is complete when2 independent nuclei have formed
- 16cytokinesis-immediately follows mitosis
-the cytoplasm divides to form two daughter cells
-each daughter cell has its own nucleus and complete set of organelles - 17S phase/Interphase-keeps DNA identical
-The instructions for making cell parts are encoded in the DNA, so each new cell must get a complete set of DNA molecules - 18"social control" over cell divisionif not regulated, cell division could turn into cancer from overriding the tumor supressor signals and cause cancer
- 19function of cyclins-cyclins bind to and activate cyclin-dependent kinases (Cdks), which phosphorylate other proteins involved in cell cycle.
- 20function of MPF (maturation promoting factor)-a cyclin-Cdk complex that participates in enzyme activation, nuclear envelope breakdown, and chromosome condensation.
- 21MPF is atwo-protein complex (heterodimer), consisting of cyclin and cyclin dependent kinase
- 22Examples of how cancer cells can override the normal controls on the cell cycle?Angiogenesis – tumor gets its own blood supply
• Loss of contact inhibition – cells will
now pile up on each other
• Loss of anchorage dependence
– enables a cancer cell to move
to another location - 23Mitotic spindle-made up of microtubules called spindle fibers
-forms from microtubule organizing center - 24kinaseco-ordinate the proper timing and fidelity of processes including centrosomal functions, spindle assembly and microtubule-kinetochore attachment, as well as sister chromatid separation and cytokinesis
- 25cyclin-dependent kinasephosphorylate other proteins involved in cell cycle
- 26kinetochoremicrotubules pull chromosomes to the poles of the cell during mitosis
- 27centrioleslocated inside the centrosome: in a pair
- 28centrosomethe microtubule organizing center
- 29nucleosomea structural unit of a eukaryotic chromosome, consisting of a length of DNA coiled around a core of histones.
- 30histoneany of a group of basic proteins found in chromatin
- 31sister chromatidschromatids from the same chromosome
- 32chromosome-contain a single long
double helix of
deoxyribonucleic acid
(DNA)
-are wrapped
around proteins - 33centromerespecialized region that joins chromatids
- 34chromatinthe material of which the chromosomes of organisms other than bacteria (i.e., eukaryotes) are composed. It consists of protein, RNA, and DNA
- 35tubulina protein that is the main constituent of the microtubules of living cells
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- Fichas sobre cell cycle and mitosis, creado por Christina Stefano el 20/03/2015.
- Creado por
- Christina Stefano
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