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35 Cards in this Set
- Front
- Back
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Multicellular organisms depend on cell division for |
Development from fertilized cells Growth Repair |
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Genome |
All Dna in a cell |
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Chromosomes |
Dna tightly packed in a cell |
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Somatic cells |
Non reproductive cells with two sets of chromosomes, diploid |
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Gamete |
Reproductive cells (sperm and egg) Have half as many chromosomes as somatic, haploid |
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Chromatin |
Eukaryotic chromosomes consisted of this... Complex of Dna and protein that condenses during cell division |
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Sister chromatids |
Each duplicated chromosome has this...These separate during cell division |
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centromere
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is the narrow "waist" of the duplicated chromosome, where the two chromatids are most closely attached
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Mitosis,
Cytokinesis |
the division of the nucleus
the division of the cytoplasm |
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Meiosis
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yields nonidentical daughter cells that have only one set of chromosomes, half as many as the parent cell (produces gametes)
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The cell cycle consists
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Mitotic (M) phase (mitosis and cytokinesis) Interphase(cell growth and copying of chromosomes in preparation for cell division)
Interphase (about 90% of the cell cycle) can be divided into subphases: G1 phase (first gap) S phase (synthesis) G2 phase (second gap) |
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Prophase
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Chromosomes are condensing |
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Prometaphase |
Chromosomes apparent, nuclear envelope fragments |
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Metaphase |
Spindle complete, chromosomes attach to microtubles, chromosomes aligned along metaphase plate |
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Anaphase |
sister chromatids seperate |
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Telophase |
daughter nuclei form(Cytokinesis is well underway late in this phase) |
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centrosome
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the microtubule organizing center of the cell
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An aster
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(a radial array of short microtubules) extends from each centrosome
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kinetochores
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During prometaphase, some spindle microtubules attach to the _______ of chromosomes and begin to move the chromosomes
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metaphase plate
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chromosomes are all lined up at the this, the midway point between the spindle’s two poles.
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Nonkinetochore
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microtubules from opposite poles overlap and push against each other, elongating the cell
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a cleavage furrow in animal cell and a cell plate in plant cells
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forms during cytokinesis
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binary fission
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Prokaryotes (bacteria and archaea) reproduce by a type of cell division
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origin of replication
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In binary fission, the chromosome replicates beginning here
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cell cycle control system
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The sequential events of the cell cycle are directed by a distinct _________, which is similar to a clock,
which has specific Checkpoints where the cell cycle stops until a go-ahead signal is received. |
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G0 (Gzero) phase
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If the cell does not receive the go-ahead signal, it will exit the cycle, switching into a nondividing state.
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cyclins and
cyclin-dependent kinases (Cdks) |
Two types of regulatory proteins are involved in cell cycle control
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MPF (maturation-promoting factor)
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is a cyclin-Cdk complex that triggers a cell’s passage past the G2 checkpoint into the M phase
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growth factors, external signals
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proteins released by certain cells that stimulate other cells to divide
For example, platelet-derived growth factor (PDGF) stimulates the division of human fibroblast cells in culture |
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internal signal
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An example is that kinetochores not attached to spindle microtubules send a molecular signal that delays anaphase
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density-dependent inhibition
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Another example of external signals in which crowded cells stop dividing
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anchorage dependence
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Most animal cells also exhibit this, in which they must be attached to a substratum in order to divide
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transformation
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A normal cell is converted to a cancerous cell.
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benign tumor
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If abnormal cells remain at the original site,
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Malignant tumors
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invade surrounding tissues and can
metastasize, exporting cancer cells to other parts of the body, where they may form secondary tumors |
