Download Homeostasis Student

Mr. Drake
 Membrane
is “_____________________”:
only allows certain things to enter the
cell
 The lipids prevent too much water from
entering or exiting the cell
 Small, uncharged,
molecules pass through
easily (O2, CO2).
 Concentration
of molecules is equal
inside the cell and outside of the cell
 This is how we achieve homeostasis
 The cell is always moving towards
equilibrium
Concentration –
amount of molecules
in a given space
Example:
5 grams/liter
 Transport
• 1)
• 2)
• 3)
that does NOT require energy
 Simplest
type of transport
 Movement of molecules from an area of
_______________________(MORE)to an
area of ______________________(LESS)
 ______________________: difference in
concentration of molecules across a
space
 Molecules move down their
concentration gradient
 Molecules will do this without energy
 Cell
membranes are selectively
permeable
 Go from high concentration to low
concentration
 Depends on the size of the
molecule, smaller is better
 Calcium, sodium and water
pass easily
 Movement
of _________ across the cell
membrane
 Again, it goes from high to low
concentration
 Does not require energy
it is passive
 _____________: having
a lower solute
concentration, and therefore a higher
water concentration, relative to another
solution.
 Example: If the cell is sitting in a
hypotonic solution, then water will flow
into the cell.
 _____________: Having a greater solute
concentration, and therefore a lower
water concentration, relative to another
solution.
•_____________-having an equal solute concentration
and water concentration relative to another solution.
•If a cell is sitting in an isotonic solution, water will flow
into and out of the cell at equal rates.
Direction of osmosis
Solution outside of cell
Direction of Osmosis
Hypotonic
Water into the cell
Hypertonic
Water out of the cell
Isotonic
Into and out of the cell at equal rates
=
 Most
get to equilibrium easily as water
passes across membranes
 Cells live in a ______________
environment, water all around them
 If too much water enters the cell it will
burst
 Cells must manage water and solute
levels to prevent dehydration
 For
molecules that can’t pass through the
membrane
 Either too large or not lipid-soluble
 Proteins in the membrane help push
them through
 From high to low concentration
 The proteins will change their shape and
this pushes the molecules through
 Ion
channels in the cell membrane act
like gates in a fence
 Allow sodium, calcium, potassium, and
chloride to flow into cell (Ca+, K+, Cl-)
 Useful in nerve and muscle cells
 1)
Sodium-Potassium Pump
 2) Endocytosis
 3) Exocytosis
 From
_________________concentration—
AGAINST concentration
gradient
 Uses energy-Active
 1) ______________________: in
muscle cells uses energy
 Creates electrical impulses
like in nerve cells
 Push
proteins and hormones “up” the
concentration gradient
 Key to survival of animal cells
 Sodium potassium pump: Animals must
have more sodium outside and potassium
inside to allow for energy production in
cells
 Can move small and large molecules
using this method
 2)
________________: large molecules like
food into the cell
 3)________________: Large molecules out
of the cell
 Opposite
of endocytosis, cell releases
large amounts of material through the
membrane
 Removes waste from the cell
 Important to maintaining homeostasis in
cells
 Cells
of animals live in a salty or “saline”
solution
 This allows them to survive in a variety of
different environments
 Cells must maintain fluid levels or they
die
 Most animals will have a kidney type
organism to manage these levels in the
body
 Filter
the blood of animals through
osmosis and diffusion
 Prevent dehydration and maintain fluid
levels
 Prevent toxins from building up in the
blood
 Eliminate swelling in the body
 When
Kidneys fail harmful toxins build
up in the blood
 CKD (chronic kidney disease), cancer,
aging and drug/alcohol abuse lead to
kidney failure
 Tubing that removes toxins, Takes 3-4
hours 3 times a week