Download Cell Shape and Size ppt

Why
is diffusion and osmosis
important to the cells in your
body?
 Transport
materials (nutrients,
oxygen and wastes) into and out of
the cells.
 If cell doesn’t get nutrients and
oxygen, or get rid of wastes in a
timely manner, it will die.
Shape
of the cell reflects its function
 Examples:
Red Blood cell
 Nerve cell
 Skin cell

Brainstorm:
Why
can't cells continue to grow
larger and larger to become giant
cells, like a blob?
Why
are most cells, whether from
an elephant or an earthworm,
microscopic in size?
Individual
cells are small—animal
cell about 0.01 to 0.05mm in
diameter.
If cell is too big, materials
(nutrients, waste, water) flowing
into and out of the cell takes too
long.

vs.
How
does this prevent an amoeba
from reaching the size of a pro
wrestler and engulfing your legs when
wadding into a murky lake?
 An
amoeba the size of a human could
never move materials across its membrane
fast enough to satisfy such a large blob of
cytoplasm.
 Surface-to-volume
ratio limits cell size.
Animal
Cells – Limited cell growth
 If
cells get too big - cannot get rid of wastes or
get what it needs to function at the rate
needed.
 Cell has 2 options:
 Die
 Divide
 Plant
Cells - Have larger sizes due to large
central vacuole which is responsible for their
growth.
Which
one has more cells - mommy or foal?
 Mommy
horse. Why?
 Older horse has millions more cells
compared to the foal because it has more mass.