Cellular Reproduction Flashcards
life cycle of a cell consists of interphase and mitosis
cell cycle
active, non-dividing period between cell divisions
genetic material in the form of chromatin
nucleus has a membrane; nucleoli are present
interphase
interphase consists of 3 periods:
g1 - period of growth
s (synthesis) - DNA replication
g2 - second growth prior to mitosis
period of active nuclear division of somatic (body) cells
produces 2 diploid (2n) daughter cells which are identical to their parent cell
mitosis: division of nucleus
chromatin gradually shortens and thickens, becomes chromosomes
chromosomes consists of paired structures called sister chromatids
formation of mitotic spindle
disintegration of nuclear envelope
prophase
cell growth and metabolism phase
g1, g2 phase
DNA synthesis that occurs betwen G1 and G2, duplication of chromosome occurs
synthesis
nucleolus disappears
mitotic spindle forms
duplicated chromosomes appear as sister chromatids
centrosomes move in opposite directions
prophase
nuclear envelope disappears
chromosomes become condensed
sister chromatids captured by kinetochore microtubules
mitotic spinde attaches to kinetochore
prometaphase
centrosomes now at opposite side of cells
chromosomes align at metaphase plate
metaphase
sister chromatids break apart from each other
shortening of microtubules pulls chromatid toward opposite ends
cell elongates
anaphase
start of cytokinesis and formation of cleavage furrow
nuclear envelopes and nuceleolus form
chromosomes become less condensed
mitotic spindles disappear
telophase
overlaps with telophase
in animals, at the center of an elongated cell, a cell plate is formed (a partial new cell wall assembled by vesicles)
in animals, a ring of microfilament contracts, pinching the cell inward (cleavage furrow)
cytokinesis: division of cytoplasm
contains material that functions in organizing mitotic spindles
centrosome
attachment point of two sister chromatids
centromere
