CH4 - the cell cycle Flashcards
the stages of the eukaryotic cell cycle
interphase, mitosis, cytokinesis
interphase checkpoints
G1 - ensures cells are prepared for the replication of DNA
S - DNA replication
G2 - cell growth and proof reading
stages of mitosis
prophase, metaphase, anaphase, telophase
prophase
DNA supercoils and chromosomes condense
nuclear membrane breaks down
paired centrosomes move to poles
metaphase
microtubule spindle fibres connect from centrosomes to centromeres
spindle fibres contract, causing the chromosomes to align at the centre
anaphase
spindle fibre contraction caused the sister chromatids to separate and become identical chromosomes that move to opposite polls of the cell
telophase
the chromosomes de-condense
nuclear membranes reform around the two identical chromosome sets
cytokinesis
animal cells:
microtubule filaments form a ring (cleavage furrow) which contracts
plant cells:
vesicles form at the centre of the cell and fuse to form an end plate
functions of mitotic division
tissue repair, organismal growth, asexual reproduction
what is mitosis
the division of a cell to produce two genetically identical daughter cells
binary fission
circular chromosome uncoiled and DNA is replicated
cell elongates and circular chromosomes move to opposite ends
cell begins cytokinesis by creating a septum
new cell wall and membrane are formed
or
D - DNA replication
E - elongation
S - septum formation
C - cell division
what is binary fission
a method of cell replication used by prokaryotes
what is the role of apoptosis
removes cells that are not needed or not developed and recycles excess cells to reduce energy costs
intrinsic pathway
mitochondria
extrinsic pathway
death receptor
