2. Skin cancer - the abnormal
growth of skin cells - most
often develops on skin
exposed to the sun.
1. Growth –from a baby to an adult – you need more cells.
2. Repair – if you get a cut – you need more cells to fill in the
cut.
3. Replacement – when cells die – they need to be replaced.
Fun fact: Skin cancer is the abnormal growth of cells – they
don’t know when to stop making more – this produces a tumor.
3. The cell life cycle
consists of:
Interphase -normal activities for the cell
Mitosis (5 steps):
1.Prophase – nucleus dissapears
2. Metaphase – chromosomes line up
3. Anaphase – chromosomes separate
4. Telophase – nuclei form
Cytokinesis - cell splits in two
Back to Interphase – normal activities for the cell
5. • G1 phase: Cell grows in size
• S phase: Chromosomes are
copied - the number doubles.
(In the microscope, DNA
appears as threadlike
spaghetti called chromatin).
• G2 phase: Cell double checks
that DNA has been copied and
cell has enough organelles for
the upcoming split
Draw this
7. • Nucleus starts to
disappear.
• DNA Chromatin coils up
into chromosomes.
• Centrioles appear and
begin to move to opposite
end of the cell.
• Spindle fibers form
between the poles.
centriole
Draw this
19. • Cell membrane
moves inward
to create two
daughter cells
– each with its
own nucleus.
• In plant cells, a
cell plate forms
in between the
daughter cells.
Draw this
20. • The cell wall makes plant cells rigid, so they can’t move inward
and separate like animal cells can.
• Vesicles filled with cell wall parts are towed to the middle of the
cell.
• They fuse together, forming a “cell plate.”
• The cell plate becomes the new cell wall.