cells division Flashcards
cell cycle
regulated cycle of division with intermediate growth periods.
1. interphase 2. mitosis/meiosis 3. cytokinesis
G1
period of cell growth before DNA is duplicated
G2
period after DNA is duplicated. cell prepares for division
Synthesis phase
period when DNA is duplicated
prophase
replicated chromosomes coil up and contract
centrioles move to opposite poles of the cell
nuclear membrane breaks down
protein microtubules develop from each centriole, forming spindle fibres
chromosomes become visible
metaphase
spindle forms across cell
each chromosome moves to equator and becomes attached to spindle by its centromere
sister chromatids are orientated towards opposite poles of the cell
anaphase
centromere splits and sister chromatids separate
they move to opposite poles of spindle
there are lots of mitochondria surrounding spindle to provide energy for movement
telophase
chromatids are at opposite poles of cell
nuclear membrane forms around each set of chromatids
cytokinesis divides cytoplasm into 2 cells along equator line
chromatids uncoil
locus
position of a gene on a chromosome or DNA molecule
meiosis
prophase 1
chromosomes condense
nuclear envelope breaks down
crossing over happens
metaphase 1
pairs of homologous chromosomes move to equator
anaphase 1
homologous chromosomes move to opposite poles of cell
telophase 1 and cytokinesis
chromosomes gather at poles
cytoplasm divides
DNA is still doubled
