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23 Cards in this Set
- Front
- Back
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Chromatin
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- building material of chromosomes
- complex of DNA and proteins |
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Chromosomes
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- consist of one very long, linear DNA molecules with many protiens
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Duplicated chromosome
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- consists of two sister chromatids connected by sister chromatid cohesion
- each contains a copy of the DNA molecule |
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Chromatid
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- sister chromatids: joined copies of the original chromosome
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Centrosome
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- subcellular region containing material that functions thorough the cell cycle to organize the cell's microtubules
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Spindle Pole
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where microtubules connect and extend from
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Kinetochore
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- a structure of proteins associated with specific sections of chromosomal DNA at each centromere
- some spindle microtubules attach - each sister chromatid has one |
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Chromatin Condensation (tight packing)
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- begins during prophase when the chromosomes become visible
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Chromosome Decondensation (unpacking)
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- during telophase when chromosomes become less condensed
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Prophase
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Step 1 of mitosis
- chromosomes condense - nucleoli disappear - miotic spindle begins to form |
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Prometaphase
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Step 2 of mitosis
- nuclear envelope fragments and microtubules extend from each pole - some attach to one kinetochore on each chromosome |
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Metaphase
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Step 3 of mitosis
- chromosomes convene at the metaphase plate |
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Anaphase
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Step 4 of mitosis
- sister chromatids separate and move to opposite ends of the cell - the cell elongates |
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Telophase
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Step 5 of mitosis
- daughter nuclei form - nucleoli reappear - chromosomes decondense |
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Cytokenisis
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in animals:
- a cleavage furrow forms in plants: - a cell plate forms to become a cell wall |
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Mitosis
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- 10% of cell cycle
- used for growth, repair/regeneration - occurs in somatic (body) cells - produces daughter cells identical to the parent |
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Meiosis
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- used for reproduction only
- produces daughter cells with 1/2 the number of chromosomes as the parent |
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M phase
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miotic phase
- includes both mitosis and cytokinesis - usually the shortest part of the cell cycle - alternates with the much longer interphase (90% of cycle) |
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Interphase
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- 90% of cell cycle
- the cell that is about to divide grows and copies its chromosomes in preparation for division |
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G1 Phase
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First gap of interphase: longest part
- cell grows to functional size - makes enzymes - makes nucleotides (building materials) |
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S Phase
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Synthesis of interphase
- chromosomes are copied (DNA synthesis) |
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G2 Phase
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Second gap of interphase
- cell grows even more - centrosome is duplicated (for microtubules) |
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Frequencies of mitosis
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1) continuous -> skin, blood, GI tract cells (can re-enter cell cycle at G0)
2) based on need -> liver (can re-enter cell cycle at G0) 3) rare/never -> neurons, muscle cells (permanent G0 in an adult) -- most human cells are in G0 |
