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karyotype
the chromosome complement of an individual TERM 2
Interphase
DEFINITION 2 G1: interphase, gap before duplication S: chromosome duplication, DNA synthesis G2: interphase, gap before mitosis TERM 3
Metaphase chromosomes
DEFINITION 3 metacentric chromosomes acrocentric chromosomes TERM 4
Mitosis
DEFINITION 4 a nuclear division that precedes division of somatic cells - function: equal distribution of duplicated chromosomes between the nuclei of daughter cells -result: genetically identical cells forming a cell clone TERM 5
Four phases of mitosis
DEFINITION 5 Prophase (prometaphase) metaphase anaphase telophase
Interphase
Interphase is the phase of the cell cycle in which the cell spends the majority of its time and performs the majority of its purposes including preparation for cell division. - centrosomes have duplicated - nuclear has begun to dissolve
- condensed chromosomes in nucleus TERM 7
Prophase
DEFINITION 7 Prophase, from the ancient Greek - (before) and (stage), is a stage of mitosis in which the chromatin condenses into a highly ordered structure called a chromosome in which the chromatin becomes visible. -mitotic spindle begins to form - kinetochores appear -chromosomes condensing, two sister chromatids become visible` TERM 8
Prometaphase
DEFINITION 8 Prometaphase is the phase of mitosis following prophase and preceding metaphase, in eukaryotic somatic cells. - centrosome at spindle pole -nuclear envelope completely dissolved -chromosomes in active motion -kinetochore microtubules attach TERM 9
Metaphase
DEFINITION 9 a stage of mitosis in the eukaryotic cell cycle in which condensed & highly coiled chromosomes, carrying genetic information, align in the middle of the cell before being separated into each of the two daughter cells. -chromosomes aligned at equator; form "metaphase plate" -centrosome at spindle pole TERM 10
Anaphase
DEFINITION 10
- chromosomes separate - spindle pole moving outward - kinetochore microtubule shortens. A) shortening of kinetochore microtubules; movement of daughter chromosomes to polse; forces generated mainly at kinetochores B) a sliding force is generated between overlap microtubules from opposite poles to push the poles apart; a pulling force acts directly on the poles to move them apart
Crossing over
the genetic exchange between nonsister chromatids of a homologous pair -on average 2-3 crossovers/chromosome pair in humans -alleles residing on the paternal and maternal chromosomes are recombined GENETIC RECOMBINATION TERM 17
Metaphase I
DEFINITION 17 Tetrads line up along the METAPHASE PLATE; each chromosome of a homologous pair attaches to fibers from the opposite poles; sister chromatids attach to fibers from the same pole TERM 18
Anaphase I
DEFINITION 18 the centromere does not divide, but the chiasmata migrate off chromatid ends and homologous chromosomes move to opposite poles TERM 19
Telophase I
DEFINITION 19 nucleoli and nuclear envelop re-forms; does not exist in all cells TERM 20
Three general phases of germ cell formation:
DEFINITION 20 -proliferation -growth -maturation
