Why do cells reproduce?
- reproduction (asexual and sexual)
- growth
- repair + healing
G1
1st growth phase
performs cellular function and is active
many cells stay in this phase and they don't divide (G0) )examples are nerve cells and stems of plants)
(check point 1)
check point one
1) is there a need for cells?
2) is the DNA undamaged?
3) is there sufficient cell growth (from G1)
S (synthesis phase)
- synthesis of DNA
- cell has 2 identical strands of DNA when this process is finished (sister chromatids)
G2
2nd growth phase = final mitosis prep
Continued growth from G1 (checkpoint 2)
check point 2
1) was the DNA duplicated properly?
2) was there sufficient growth?
Mitotic phase (cell division)
nuclear divison
each of the new daughter cells gets a copy of DNA
each daughter cell starts back at G1
cytokinesis
splitting of the cells into two
interphase
THE PHASE BEFORE MITOSIS
G1 / G2 / S
GAP PHASES ARE GROWTH AND S IS DNA BEING "DUPLICATED"
prophase
DNA- condenses into chromosomes with sister chromatids
Nucleus - begins to break down
centrioles - move ot the opposite sides of the cell
spindle - begin to form
metaphase (M = MIDDLE)
DNA- chromosomes with sister chromatids
Nucleus - gone (nuclear envelope dissolved by enzymes)
Centrioles - opposite sides of the cell
spindle - formed, moves chromosomes into the center
anaphase
DNA- sister chromatids torn apart at centomere
Nucleus - gone
centrioles - at opposite sides of the cell
spindle - pulls apart the sister chromatids
telophase
DNA - sister chromatids pulled towards ends - and chromatin reforms
Nucleus - reforming
Centrioles - opposite sides of the cell
spindle - formed, pulles sister chromatids to the ends of the cell
cytokinesis -
USUALLY HAPPENS AT THE SAME TIME AS TELOPHASE
plants - cell plate begins to form in between daughter cells
Animals - cytoplasm pinches in
Order of mitosis
interphase, prophase, metaphase, anaphase, telophase cytokinesis
2 process during interphase that is necessary for nuclear division
growth of the cell and synthesis of the DNA
the most cell growth happens during -
G1 phase
DNA replication occurs
in the S phase
the cell is prepared for mitosis in what phase
G2 phase
the phase where mitosis and cytokinesis takes place
cell division phase
if a human cells has 46 chromosomes how many will each daughter cell have
46 cells
chromatin
DNA as strands (DNA and protein)
chromosomes
the condensed version of DNA (raveled chromatin)
centromere
region of chromosome attachment (center where sister chromatids attach)
chromatid
one half of a duplicated chromosome
sister chromatid
two halves of a chromosome attached with a centromere
in mitosis the cells are
the cells are identical
cancer is caused by
rapid or crazy cell growth
tumors are caused by clumps of excessive cells
and G1 is the most affected
interphase
is where the cell spends the most time
G0
cells in G0 don't go through the cell cycle
If DNA was damaged and the cell continued to go through the cell cycle
is would cause the mutation to spread through out the rest of the organism
Surface Area and Volume
the smaller the cell the less volume it has, meaning is has a larger SA/V ratio
Surface Area / Volume and diffusion
the smaller the cell the more efficient the diffusion