cell cycle and division (2) Flashcards
non division phase
interphase (growth, preparation)
division phase
mitosis (division of nucleus), cytokinesis (division of cytoplasm, organelles)
when can a cell not go through division?
other cells inform the cell that more cells of that type are not required
not enough nutrients are available to provide for cell growth
DNA has not replicated
DNA is damaged
when are the 3 “checkpoints”?
G1 => S1 (is DNA intact)
G2 => M (has DNA been replicated)
metaphase => anaphase (are chromosomes aligned at centre)
chromatin
loose, stringy mass where chromosomes cannot be seen
chromosome
during mitosis, DNA coils and chromosomes can be seen
what are 2 types of chromosome appearances?
single stranded
double stranded
centromere
holds double stranded chromosomes together
chromatid
each strand in a double stranded chromosome
sister chromatids
two identical copies of a chromatid connected by a centromere
homologous chromosomes
2 identical pairs of chromotids
order of cell cycle events
interphase prophase metaphase anaphase telophase cytokinesis
what is the longest phase?
interphase
interphase
cells do ________
whatever activities it is meant to do and prepare for cell division
how does a cell prepare for division?
growing
making more organelles
replicating DNA
prophase
chromatin _______ and chromosomes become ______
condenses / visible
prophase
nuclear membrane starts to ______
break down
prophase
nucleolus ______
disappears
prophase
centrosomes move toward _________ and begin to form ______
opposite ends of cell / spindle fibres
metaphase
chromosomes line up ________
along centre of cell
metaphase
centrioles reach ________
opposite ends of cell
metaphase
each centromere attaches to ______
2 spindle fibres (one on each end)
metaphase
nuclear membrane is _____
completely dissolved
anaphase
daughter chromosomes are pulled to _________
opposite side of cell
anaphase
the centromere ________ and the chromatids _________
breaks apart / separate
anaphase
spindle fibres _______
retract
telophase
two ___________ are formed
daughter nuclei
telophase
spindle fibres ________
start to disappear
telophase
______ begins to form around the nucleus at each end of the cell
new nuclear membrane
telophase
nucleolus ______
appears
telophase
chromosomes reach ______
opposite ends of cell
telophase
chromosomes become _______
less coiled and harder to see
cytokinesis
occurs during _______
late telophase
cytokinesis
cytoplasm and organelles ________
divide into two equal parts
cytokinesis
the division of organelles produces ______
two genetically identical daughter cells
cytokinesis: animal cells
a ring of _________ around the middle of the cell starts to contract
specialized protein
cytokinesis: animal cells
cell membrane pinches in and forms _______
cleavage furrow
cytokinesis: animal cells
the parent cell is pinched until it divides into _______
two daughter cells
cytokinesis: plant cells
Golgi bodies start to produce _________ which _____________
small vesicles / carry the materials needed to form a new cell wall
cytokinesis: plant cells
vesicles line up between the two net nuclei, forming a ______
cell plate
cytokinesis: plant cells
cell plate grows outwards and _______
joins the old cell wall
cytokinesis: plant cells
the new ________ forms inside the new cell wall
cell membrane
cytokinesis: plant cells
the parent cell is divided into _________
two daughter cells
