the cell cycle and cell division Flashcards
what are 3 reasons cell division is important?
healing and tissue repair
growth
reproduction
what is the purpose of healing and tissue repair?
replace dead cells
what is the purpose of growth?
increase number of cells to keep cells small and constant
what is the purpose of reproduction?
perpetuate life
the cell surface area must be big enough for ____________
entry of oxygen and nutrients
as cells use nutrients, they produce more organelles and cytosol = ____________
becomes bigger
more functioning organelles = ____________
more nutrients needed, more waste produced
why can’t a cell get too big?
it will not have enough surface area for all the nutrients it needs and waste it produces
the cell cycle consists of two phases: _____ and _____
cell division / interphase
different types of cells spend different ____________
amounts of time in each stage
what is the cell cycle?
a continuous sequence of cell growth and division
what stages does the cell cycle include?
interphase, mitosis, cytokinesis
what is interphase?
periods of growth in the life of a cell
what phases does interphase include?
growth and DNA reproduction
prophase
the phase of mitosis in which sister chromatids condense and chromosomes become visible
prophase:
duplicated chromosomes _____ and ______, become visible
shorten / thicken
prophase:
duplicated chromosomes consists of _______
2 chromatids joined by a centromere
prophase:
nuclear membrane ________
dissolves
prophase:
centrioles move to ________
opposite poles
prophase:
spindle fibres _______
appear
metaphase
the phase of mitosis in which the chromosomes are aligned across the centre of the cell
metaphase:
duplicated chromosomes line up in the _______
middle of the cell
metaphase:
spindle fibres attach to ________
centromeres
anaphase
the phase of mitosis in which the centromere splits apart and the chromatids are pulled to opposite sides of the cell by the spindle fibres
anaphase:
spindle fibres pull __________
each chromatid to the duplicated chromosome to opposite poles (chromosome splits)
telophase
the phase of mitosis in which two daughter nuclei are formed
telophase:
chromosomes reach ________
the opposite poles
telophase:
nuclear membrane begins to ______
form
telophase:
spindle fibres _______
disappear
telophase:
cytoplasm and organelles separate into _______
roughly 2 equal parts
DNA is divided into segments called _____, each of which provides the instructions for making a different ______
genes / protein
different types of cells spend _________
different amounts of time in each stage
during cell division, each daughter cell needs a copy of all ________
chromosomes
the copying process of chromosomes is called _________
DNA replication
a parent cell must make a copy of every chromosome before __________
it divides
just before the cell gets ready to divide, the chromosomes become _______
thick and bulging
mitosis
the process by which the duplicated contents of the cell’s nucleus divide into two equal parts
cytokinesis
following mitosis, the separation of the two nuclei and cell contents into daughter cells
cytokinesis in plant and animal cells:
a ring of __________ around the middle of the cell starts to _______
specialized proteins / contract
cytokinesis in plant and animal cells:
the cell membrane is pinched until the parent cell __________
is divided into two parts
cytokinesis in plant and animal cells:
each daughter cell has a complete set of _____________
chromosomes in a nucleus and its own share of cytosol and organelles
cytokinesis in plant cells:
what organelle changes the process?
cell wall
cytokinesis in plant cells:
Golgi body starts to produce ________; sacs carry materials needed to make _______
small vesicles / a new cell wall
cytokinesis in plant cells:
vesicles line up between two nuclei, forming _________
a cell plate
cytokinesis in plant cells:
cell plate grows outwards and joins ______, dividing ________
old cell wall / cytoplasm in two
cytokinesis in plant cells:
new ______ form inside cell walls
membrane
