Mitosis Flashcards
Why does mitosis occur?
growth
repair / heal
asexual reproduction
What are some examples of cells that are constantly dividing?
epithelial
intestinal
What are some examples of cells that divide rarely / never?
brain - nerve
spinal cord - nerve
cardiac (heart muscle)
What are the methods a cell can divide?
mitosis
meiosis
What is the MAIN difference between mitosis and meiosis?
mitosis is division of somatic cells
meiosis is creation of new sex cells
What are somatic cells?
all cells except for sex cells
genes will not be passed on
What is a germ cell?
a cell destined to gamete
genes will be passed on
What is diploid (2N)?
a cell pair with 2 chromosome sets in each of its cells
all body cells (SOMATIC CELLS)
What is haploid (N)?
a cell with 1 chromosome set in each cell
all gamete cells
Draw and annotate a somatic cell
CONGRATTTSSS YOOOU DDIIIDD IT !!!
What are the features of a somatic cell?
plasma membrane spindle microtubules sister chromatids centromere centriole telomere
What are the characteristics of mitosis?
diploid cell will produce diploid cell
chromosome number remains the same
DNA remains identical of parent cell one cell (2N) will produce 2 cells (both 2N)
nucleus of cell divides = 2 nuclei
What is mitosis?
the part of cell division that results in 2 identical daughter cells from a single parent cell
What are the stages of mitosis?
Interphase Prophase Metaphase Anaphase Telophase Cytokinesis
What happens in interphase?
does not involve cell division
DNA replicated
New organelles synthesised
cell increases in size (cytoplasm volume increases)
What happens in prophase?
DNA supercoils - chromosomes appear
chromatin condenses and becomes sister chromatids (visible under light microscope)
centrioles seperate and spindles form
centrosomes move to opposite poles and spindle fibres form between them
LONGEST PHASE
What happens in metaphase?
chromosomes line up at cell equator
spindle fibres attach to the centromere of each pair of sister chromatids
SHORTEST PHASE
What happens in anaphase?
continued contraction of microtubule spindle fibres cause separation of sister chromatids
chromatids now referred to as chromosomes
chromosomes move to opposite poles
What happens in telophase?
microtubule spindle fibres disappear
chromosomes uncoil to chromatin (no longer visible under light microscope)
new nuclear membranes reform around chromosomes
What happens in cytokinesis (in general)?
cell fully separates into 2 identical daughter cells
What happens in cytokinesis for animals?
a contractile ring (made of actin filaments) forms inside plasma membrane and pulls the cell equator inwards.
this creates a fissure called: CLEAVAGE FURROW
eventually splits into 2
What happens in cytokinesis for plants?
in telophase golgi vesicles moved to centre of cell to form phragmoplast (vesicular structure). There they fuse to become cell plate, which will then become cell wall.
eventually splits into 2
Why do plant and animal cells have different cytokinesis steps?
because the plant cell has a cell wall and the animal cell does not
