Transcript Cell Membrane - Goshen Community Schools

Transport
Chapter 9
How does stuff get in and out of a cell
through the cell membrane?
Bilayer
Which one?
Freeze
Fluid Mosaic Model
Cell Membrane
Controls what enters & leaves the cell
Only certain kinds
of molecules can
go across
= SELECTIVELY
PERMEABLE
____________________
(Semi-permeable)
How do molecules move?
All molecules will move automatically
from a region of ______
HIGH concentration
to a region of ______concentration.
LOW
DIFFUSION
_______________
What if the HIGH and LOW
places are on different sides of a
cell membrane?
Molecules will still
go from HIGH
to LOW if the
cell membrane
will let them
through!
PROBLEM WITH CELLS
What if a cell needs a molecule that can’t
pass through the cell membrane easily?
Need a way to move molecules
across that can’t go by
DIFFUSION
Carrier Proteins :
_____________________________
INTEGRAL PROTEINS that
help molecules go across
Vesicles :
_______________
Small membrane sacs that
carry molecules
2 KINDS of TRANSPORT
• ______________
PASSIVE
TRANSPORT
Does NOT require energy
ACTIVE
• _____________
TRANSPORT
Requires energy
Some molecules can just pass
right through the bilayer using
DIFFUSION
EXAMPLE: oxygen,
___________________
carbon dioxide
Carrier
Proteins
PASSIVE TRANSPORT
• Diffusion
• Osmosis
• Facilitated Diffusion
DIFFUSION
OSMOSIS
• When water molecules
move across membrane
from HIGH to LOW it
is called
OSMOSIS
___________________
FACILITATED DIFFUSION
FACILITATED DIFFUSION
PASSIVE (No energy needed)
HIGHER TO LOWER
CARRIER PROTEINS
GRAB & FLIP IT ACROSS
GLUCOSE
EXAMPLE: _________________
PROBLEM WITH CELLS
What if cell needs to move from
LOW to HIGH?
What if cell needs to move it fast
and not wait?
ENERGY IF YOU
NEED TO ADD __________
WANT A MOLECULE TO MOVE IN
THE OPPOSITE DIRECTION IT
NATURALLY GOES!
What organelle supplies
the energy?
ACTIVE TRANSPORT
•Na+-K+ Pump (Carrier Protein)
•Exocytosis
•Endocytosis
CARRIER PROTEINS
SODIUM-POTASSIUM PUMP
(Carrier Protein)
• ACTIVE (Uses energy)
• USES CARRIER PROTEIN
• Special just for Na+ and K + ions
• Examples in cells:
3 Na+ are pumped out of cells at
same time 2 K + are taken into cells
ENDOCYTOSIS
Brings substances into cell
• ACTIVE
• VESICLES CARRY MOLECULES
INTO CELL
– Fluid, molecules = Pinocytosis
– large particles or whole cells =
Phagocytosis
• Examples in cells:
– one celled organisms eat this way
– white blood cells destroy bacteria this way
Endocytosis
EXOCYTOSIS
Substances are released outside of cell
• ACTIVE
• VESICLES CARRY &
RELEASE MOLECULES
• Examples in cells:
–GOLGI BODIES release
packaged proteins
Exocytosis
INSIDE CELL
OUTSIDE CELL
VESICLES
3 Types of OSMOSIS
OSMOSIS
ISOTONIC:
EQUALS
Concentration outside cell ____________
concentration inside cell
Water entering = water leaving
STAYS THE SAME SIZE
so cell _____________________
OSMOSIS
HYPERTONIC:
Concentration outside cell is
GREATER THAN inside cell
____________________
More water leaves cell than enters
so cell shrinks ______________________
= PLASMOLYSIS
OSMOSIS
HYPOTONIC:
Concentration outside cell is ________________
LESS THAN
inside the cell
More water enters than leaves cell so cell
= CYTOLYSIS
expands and can burst ___________________
Animal cells
Isotonic
Hypotonic
Hypertonic
Plant cells
Isotonic
Hypotonic
Hypertonic
IS IT ISO, HYPO, or HYPER?
THE END 