Download homeostasis and transport

HOMEOSTASIS AND TRANSPORT
Cell membranes help organisms maintain _______________________ by controlling
what substances may enter or leave cells
 Homeostasis - ___________________________________________________________.
Some substances can cross the cell membrane without any input of _______________ by the cell
The movement of such substances across the membrane is known as passive transport
To stay alive, a cell must exchange materials such as ________, _________, and _______________
with its environment
These materials must cross the ___________________________________________.
Plasma Membrane
Boundary that separates the ____________ cell from it’s _____________________ surroundings.
Phospholipid bilayer (2 layers)
Controls what comes _______ and _____ of the cell with
______________________ and __________________.
(allows some molecules to move across cell membrane)
Small molecules like
can move in and out freely
Large molecules like _____________________
________________________ cannot
move easily across the plasma membrane
The Cell Membrane is _____________________
________________________ only allowing certain
molecules to pass through.
PASSIVE TRANSPORT
__________________________ required
When substances move from a __________________________________ to a
___________________________________.
Three types of passive transport:
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o
o
o
Diffusion
Passive transport:
Diffusion is the movement of molecules from
_______________________________________________________________
Substances continue to move until the molecules are _______ throughout the space =
The net movement of a substance (molecules) ________ a concentration gradient from an area of
________ concentration to an area of ______ concentration.
 _______________________________= happens anytime there is a _________
in concentration in one place compared to another.
___________ molecules can pass through the cell membrane by a process called ___________
 Examples:
Facilitated diffusion:
A type of _____________________ that requires the use of _______________________.
Facilitate means ________________.
Transport proteins help the molecules across the _____________ that ______ pass through
_________________________.
Still requires the use of _____________________!! (
)!
Uses two methods:
 ___________________________: proteins that are already embedded in the
______________________ that grabs a molecule, changes __________ to help
move the molecule, then moves the molecule to the _______________________.
 __________________________: proteins already embedded in the cell membrane
create a ___________ which the molecule can ____________________.
Osmosis
3 kinds of Osmosis in cells:
Solutions………
Solutions have two parts:
 Solute:
 Solvent:
________ is the
universal solvent!
Hypertonic Solution
________________ concentration _________________ the cell is higher (________________________)
Water diffuses _____________________________________ until equilibrium is reached
Cells will ______________ & die if too much water is lost
Plant cells become flaccid (_________); called plasmolysis
Hypotonic Solution
________________ concentration is ___________________________ the cell (_________________________)
Water moves ____________________________ until equilibrium is reached.
Animal cells ____________ & burst (lysis) if they take in too much water
~~ ______________ is the bursting of cells
Plant cells become turgid due to water pressing outward against cell wall
___________________________________ in plant cells helps them keep their shape
Isotonic Solutions
Concentration of solutes _______________________________the cell
Water moves into & out of cell at an ____________________ so there is no net
movement of water
Animal Cells
Animal cells placed into a ___________
solution will _______________ (__________).
Animal cells placed into a ___________
solution will ____________ (___________).
Plant Cells
Firmness of tension (__________________)
that is found in plant cells (cell wall) that are in a
___________ environment is called _________.
This process is called _____________________.
When the cell membrane pulls away from the cell
wall (________________) in a ____________
environment (______ of water) is called
_________________.
ACTIVE TRANSPORT
The movement of molecules (normally large) across the cell membrane in which ____________
________________.
Moves materials __________ their concentration gradient from an area of _______________
_____________________________________.
Kinds of Active Transport
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
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Sodium-Potassium Pump
The mechanism that uses __________ (____________________) released from splitting
ATP to transport Sodium (Na+)_____ of the cell and Potassium (K-) ______ the cells.
Bulk Transport
Moves ________, complex molecules such as _________ across the cell membrane.
Large molecules, food, or fluid droplets are packaged in membrane-bound sacs called
________________.
_____________________ moves large particles _______ a cell
_____________________ moves large particles _________ a cell.
There are two forms of endocytosis:
 ________________ - a form of endocytosis that transports ________ into the cell.
 ________________ - a form of endocytosis that transports ________ into the cell.