2322706
Description
Flashcards by Christina Stefano, updated more than 1 year ago
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Created by Christina Stefano
almost 11 years ago
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| Question | Answer |
| the cell cycle | -M phase -interphase: G1, S and G2 phases |
| G1 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 |
| G2 phase | -2nd checkpoint between G2 and M phases -cells stop growing if chromosome replication has not proceeded properly or DNA is damaged |
| M (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 |
| G0 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 |
| 5 stages of mitosis | -prophase -prometaphase -metaphase -anaphase -telophase |
| prophase | -chromosomes condense -first become visible under light microscope -mitotic spindle |
| mitotic 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 |
| Polar microtubules (prophase) | push the poles of the cell away from each other during mitosis |
| kinetochore microtubules (prophase) | pull chromosomes to the poles of the cell during mitosis |
| prometaphase | -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 |
| metaphase | -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 |
| anaphase | -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 |
| telophase | -a new nuclear envelope begins to form around each set of chromosomes -the mitotic spindle disintegrates -chromosomes begin to decondense |
| mitosis is complete when | 2 independent nuclei have formed |
| cytokinesis | -immediately follows mitosis -the cytoplasm divides to form two daughter cells -each daughter cell has its own nucleus and complete set of organelles |
| S 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 |
| "social control" over cell division | if not regulated, cell division could turn into cancer from overriding the tumor supressor signals and cause cancer |
| function of cyclins | -cyclins bind to and activate cyclin-dependent kinases (Cdks), which phosphorylate other proteins involved in cell cycle. |
| function of MPF (maturation promoting factor) | -a cyclin-Cdk complex that participates in enzyme activation, nuclear envelope breakdown, and chromosome condensation. |
| MPF is a | two-protein complex (heterodimer), consisting of cyclin and cyclin dependent kinase |
| Examples 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 |
| Mitotic spindle | -made up of microtubules called spindle fibers -forms from microtubule organizing center |
| kinase | co-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 |
| cyclin-dependent kinase | phosphorylate other proteins involved in cell cycle |
| kinetochore | microtubules pull chromosomes to the poles of the cell during mitosis |
| centrioles | located inside the centrosome: in a pair |
| centrosome | the microtubule organizing center |
| nucleosome | a structural unit of a eukaryotic chromosome, consisting of a length of DNA coiled around a core of histones. |
| histone | any of a group of basic proteins found in chromatin |
| sister chromatids | chromatids from the same chromosome |
| chromosome | -contain a single long double helix of deoxyribonucleic acid (DNA) -are wrapped around proteins |
| centromere | specialized region that joins chromatids |
| chromatin | the material of which the chromosomes of organisms other than bacteria (i.e., eukaryotes) are composed. It consists of protein, RNA, and DNA |
| tubulin | a protein that is the main constituent of the microtubules of living cells |
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