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cancer
- rapid uncontrolled growth of cells. metastasis - cancer cells can dislodge from a tumor and move to another area
- cannot specialize
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tumor and 2 diff kinds of tumors
- tumor - mass of cancerous cells within normal tissue
- benign tumor and malignant tumor
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what factors contribute to cancer
X rays, chemicals, asbestos, environmental factors, age, inheroted mutations
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what are technologies used to identify cancer
cell biopsies, x rays, infrared technology
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telomeres
caps at the end of chromosomes, plays a part in cell aging. reduce in length each time a cell goes through cell cycle and divides
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telomerase enzymes
functions in maintaining telomere length, cell death is slowed. telomerase is not present in most normal cells and is reactivated in cancer cells. it allows cancer cells to maintain telomere length and divide
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how many chromosomes does a human cell have
46 chromosomes
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interphase (mitosis)
cells not actively dividing, cell acitivity between cell divisions
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Gap 1, S phase, Gap 2
cell growth before DNA replication, synthesis of DNA, cell prepares for cell division (mitosis)
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prophase
chromosomes become visible, nuclear membrane fades
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metaphase
sister chromatids move to center and attach to spindle fibers
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anaphase
centromeres devide, chromarids move to opposite poles of cell
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telophase
spindle fibers dissolve, nuclear membrane forms around each mass of chromatin
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cytokinesis
division of cytoplasm and distribution of organelles to daughter cells
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how many chromosomes do gametes have
one set of 22 autosomes and a single sex chromosome (makes a total of 23 chromosomes)
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how many chromosomes do somatic cells have
22 autosome pairs plus sex chromosomes (XX or XY) which makes 46 chromosomes total
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how do you make a zygote
23 chromosome sperm + 23 chromosome egg cell produces 46 chromosome zygote
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diploid equation, haploid equation
2n = 46, n = 23
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meiosis - prophase I
duplication of DNA, spindle fibers form, nuclear membrane dissolves, centriole splits, synapsis occurs
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metaphase I
homologous chromosomes line up at equator of cell
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anaphase I
chromosomes move apart and to opposite ends of the cell
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telophase I
spindle fibers disintegrates, cytokinesis begins
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prophase II
2 cells w/ 2 chromosomes, spindle fibers form
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metaphase II
chromosomes line up at equator and each cell only has 1 of each homologous chromosome
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anaphase II
sister chromatids move away from each other
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telophase II
formation of 4 haploid cells (genetically different)
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life cycle of a plant
adult (2n diploid), meiosis spores (n haploid), mitosis gametophytes (haploid n), mitosis gametes (haploid n), fertilization zygote (diploid 2n), mitosis sporophyte (diploid 2n)
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life cycle of animal
adult (dioloid 2n = 46), meiosis gametes (haploid n=23), fertilization zygote (diploid 2n = 46), mitosis and development
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nondisjunction
2 homologous chromosomes move to same pole during meiosis or mitosis (during anaphase II)
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trisomy
23 chromosome pairs (normal gametes) + 24 chromosome pairs (abnormal gametes) = 47 chromosomes total
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monosomy
if gamete with 22 cheomosome pairs joins with a normal gamete, the zygote will have 45 chromosomes
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down syndrome
person has extra chromosome in chromosome pair #21
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turner's syndrome
monosomic disorder, with single x chromosome
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klinefelter's syndrome
inherits XX and Y chromosome
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