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Unit2(chromosome & cell cycle)
n/a
34
Biology
Undergraduate 1
02/22/2009

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Term
chromatin
Definition
the parts of DNA and proteins that make up a eukaryotic chromosome. when the cell is not dividing, chromatin exists in its dispersed form, as a mass of very long, thin fibers
Term
histones
Definition
a small protein with a high proportion of positevly charged amino acids that binds tothe negatively charged DNA and plays a key role in chromatin structure
Term
homologous chromosomes
Definition
chromosomes with the same length, centromere position, and staining pattern that possess genes for the same characters at corresponding loci. aka: homologs
Term
sister chromatids
Definition
copies of duplicated chromosome attached to each other by proteins at the centromere. when joined, make up one chromosome
-separate during mitosis & meiosis II
Term
autosomes
Definition
a chromosome that is not directly involved in determining sex; not a sex chromosome
Term
sex chromomomes
Definition
chromosome responsible for determining sex of an idividual
Term
haploid
Definition
one chromosome of each homologous pair
-gametes are haploid
Term
diploid
Definition
both homologous chromosomes present, one set inherited from each parent
-fertilization
-zygote
Term
karyotype
Definition
a display of the chromosome pairs of a cell arranged by size and shape
Term
mitotic spindle
Definition
a grouping of microtubles and associated proteins that is involved in the movements of chromosomes during mitosis
Term
kinetochores
Definition
a structure of proteins attached to the centromere that links each sister chromatid to the mitotic spindle
Term
centromere
Definition
the specialized region of the chromosome where two sister chromatids are most closely attached
Term
interphase
Definition
the period in the cell cycle when the cell is not dividing.
-during interphase, cellular metabolic activity is high, chromosomes are duplicated
Term
G0 phase(interphase)
Definition
a nondividing state occupied by cells that have left the cell cycle
Term
G1 phase
Definition
the first gap, or growth phase, of the cell cycle, consisting of the portion of interphase before DNA synthesis begins
Term
G2 phase(interphase)
Definition
the second gap, or growth phase, of the cell cycle, consisting of the portion of interphase after DNA synthesis occurs
Term
S phase(interphase)
Definition
the synthesis phase of the cell cycle;
-DNA is replicated
Term
prophase
Definition
mitotic spindle
Term
prometaphase
Definition
nuclear membrane dissapears
-kinetochores have appeared
Term
metaphase
Definition
alignment
Term
anaphase
Definition
separation
Term
telophase
Definition
reformation of nucleus
Term
cytokinesis
Definition
the division of the cytoplasm to form two separate daughter cells immediately after mitosis, meiosis I, or meiosis II
Term
cytokinesis
Definition
the division of the cytoplasm to form two separate daughter cells immediately after mitosis, meiosis I, or meiosis II
Term
G1 checkpoint
Definition
growth factors
-when stopped: 0
Term
G2 checkpoint
Definition
maturation promoting factor
-when stopped: 2x DNA
Term
M checkpoint
Definition
spindle checkpoint
metaphase -> anaphase
Term
cyclins
Definition
a cellular protein that occurs in a cyclically flutuating concentration and that regulates the cell cycle
Term
Cdk
Definition
cylcin-dependent protein kinases
-active when bound to a cycle
(MPF)
Term
MPF
Definition
mitosis promoting factor
-complex of mitotic cyclin & mitotic Cdk
Term
APC
Definition
anaphase-promoting factor
-does NOT involve a cyclin
-is NOT a kinase
Term
cancer
Definition
failure of cell-cycle control
-cancer cells divide with out control
-they have lost the dependence on growth factors
-due to mutated regulatory disease
Term
gametes
Definition
a haploid reproductive cell
-egg or sperm
-gametes unite during sexual reproduction to produce a diploid zygote
Term
Meiosis
Definition
A. only 1 replication of chromosomes (1st phase) followed by 2 nuclear & cell divisions
B. during 1st division:
-sister chromatids DON'T separate
-homologous chromosomes DO separate
(opp. of mitosis)
C. synapsis, crosing over, DNA recombination in prophase 1
D. generates diversity
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