Transcript Osmosis and Diffusion

Osmosis and Diffusion
Chapter 7 Section 3
Chapter 7 Section 3
Cell Membrane
 The
cell membrane regulates what enters
and leaves the cell to maintain homeostasis
 also
provides protection and support
 Composition:
bilayer)
 Flexible
double-layered sheet (lipid
Cell Membrane
 Semi-permeable
 May
contain protein molecules that are
embedded in the lipid bilayer which form
channels and pumps to move larger
material across the cell membrane
 Carbohydrate molecules are attached to
many of these proteins (“the claw”) and
act as chemical identification cards
Passive Transport
 Diffusion
 Move
“Down a Slide”
from high to low
 More
concentrated to less concentrated
until reaches equilibrium in the absence of
other influences
 Does
NOT require energy
Passive Transport

Simple Diffusion

diffusion across a membrane

Facilitated Diffusion

Diffusion of particle that are too large
to pass through membrane are assisted
by proteins to get from one side to
another
(channel or carrier proteins)
Diffusion of Particles
Osmosis
 Diffusion
of water across a selectively permeable
membrane
 No
energy required because moving from an area of
high concentration to low concentration
Hypotonic Solutions “HIPPO”

Solute concentration OUTSIDE cell is LOWER
(below strength) than INSIDE the cell (meaning
that MORE salt is INSIDE the cell)

Remember SALT SUCKS!!!!

Water moves INTO the cell causing it to SWELL

Cytolysis – animal cells bursting because too
much water
Hypotonic Solutions “HIPPO”
Hypertonic Solutions “HYPER”
 Solute
concentration OUTSIDE cell is
HIGHER (above strength) than INSIDE the
cell (meaning that MORE salt is OUTSIDE
the cell)
 Remember SALT SUCKS!!!!
 Water moves OUT of the cell causing it to
SHRIVEL
Hypertonic Solutions “HYPER”
Isotonic Solutions “I SO HAPPY”
EQUAL
solute concentrations
inside and outside of cell
water diffuses in and out of cell at
equal rates so cell stays the same
Isotonic Solutions “I SO HAPPY”
The Effects of Osmosis on Cells
Active Transport
 Involves
moving molecules “uphill”
against the concentration gradient
 Going up the slide
 Requires energy
 May cause protein channel to
Change shape
http://www.diffen.com/difference/Active_Transport_vs_Passive_Tr
ansport
Active Transport
Active Transport
continued…(Endocytosis)
“pac-man”
Cell
membrane encloses particle
forms a pouch (vesicle) and
pinches off into cell
Pinocytosis (solutes/fluids)
Phagocytosis (large solid particles)
Active Transport
continued….(Endocytosis)
Active Transport
continued….(Exocytosis)
 Pushing
substances out of the cell,
such as the removal of waste
 Think of a zit and popping it
Active Transport
continued….(Exocytosis)
Describe
the specialization
of cells in your own words.
Cell Specialization Chapter 7 Section 4
 Cells
develop in different ways to
perform different tasks
 Just like doctors specialize in a certain
field of study
4 levels of organization
 1.
individual cells
 2. tissues – group of similar cells working
together to perform a particular function
 Muscle
 Epithelial
 Nervous
 Connective
4 levels of organization
 3.
organs – group of tissues working
together to perform a specific function
 4.
organ systems – group of organs working
together to perform a specific function