Transporting Molecules
CELL MEMBRANE
(also called plasma membrane)
Cell membranes are made of
PHOSPHOLIPIDS
PROTEINS
________________ & __________________
CELL MEMBRANE
Proteins that stick on the surface =
(either inside or outside of cell)
PERIPHERAL
Proteins that stick INTO membrane = INTEGRAL
(can go part way in or all the way through)
GLYCOPROTEINS
Recognize
“self”
GLYCOPROTEINS are INTEGRAL PROTEINS
SELECTIVELY PERMEABLE
(semi-permeable)
Diffusion
http://lhs.lps.org/staff/sputnam/Biology/U3Cell/diffusion_1.png
Animatioin from: http://www.biologycorner.com/resources/diffusion-animated.gif
Molecules move
from “where there’s A LOT”
to “where there’s NOT”
DIFFUSION across a space
• Happens anytime there is a __________
DIFFERENCE
in concentration in one place compared
to another
= Concentration gradient
(________________________)
DIFFUSION across a space
• Molecules move automatically from an
area of _______
Higher concentration to an area
of ________
Lower concentration
• EX: _____________________
Perfume, Koolaid, popcorn,
BBQ, Bad smell in room
_____________________
http://leighhouse.typepad.com/blog/images/kool_aid.jpg
http://www.swapmeetdave.com/Humor/Farts.htm
Molecules
need to
move across
membranes
in cells
Image modiified from: http://www.accessexcellence.org/AB/GG/importProt.html
Diffusion can happen
across a membrane in a cell
…as long as membrane will let molecule through
SELECTIVELY PERMEABLE
Gas exchange between lungs and blood
happens by DIFFUSION from HIGHER
concentration to LOWER concentration
Image modified from: http://www.medaille.edu/vmacer/120_graphic_05oxygen.gif
What if cell needs to
move large or polar
molecules?
EX:
Glucose
Amino acids
What if cell needs to move a
molecule AGAINST the
CONCENTRATION
GRADIENT?
(LOW  HIGH)
Example :
Glucose into mitochondria
Image from: http://www.biologyclass.net/mitochondria.jpg
What if cell needs to move
molecules really FAST?
(can’t wait for it to diffuse)
Example in cells:
Movement of
+
+
______________
Na & K
ions sends nerve signals
http://www.steve.gb.com/images/science/neuron.png
2 KINDS of TRANSPORT
across cell membranes
PASSIVE
• ____________TRANSPORT
Does NOT require energy
•___________TRANSPORT
ACTIVE
Requires energy
Kidspiration by: Riedell
Kinds of Passive Transport
•
Diffusion
__________________________________
•Osmosis
•Facilitated
Diffusion
___________________________________
•Ion Channels
___________________________________
___________________________________
DIFFUSION across a membrane
• Happens anytime there is a __________
DIFFERENCE
in concentration on one side of the
membrane compared to the other
Molecules that move by
diffusion across membranes
in cells:
OXYGEN
______________
______________
CARBON DIOXIDE
http://www.lionden.com/cell_animations.htm
OSMOSIS
= SPECIAL KIND OF DIFFUSION
• MOVES WATER MOLECULES
• Across a MEMBRANE
http://www.Isbu.ac.uk/water/molecule.html
• From HIGHER  LOWER
DIFFUSION or OSMOSIS
HIGHER  LOWER
DIFFUSION
Can happen with or without
a membrane
Molecules that do it:
All molecules EXCEPT
water
Goes until equilibrium
Example in cells:
Oxygen & Carbon dioxide
OSMOSIS
Happens across a
membrane
Molecules that do it:
Water
Goes until equilibrium
Example in cells:
Water
What if there is a difference in
concentration but solute molecules
can’t move across a membrane?
WATER will move
until concentration
reaches equilibrium
Osmosis1
http://www.sidwell.edu/us/science/vlb6/labs/a_osmosis.gif
Kinds of Passive Transport
•
Diffusion
__________________________________
•Osmosis
•Facilitated
Diffusion
___________________________________
•Ion Channels
___________________________________
___________________________________
Facilitated Diffusion
Carrier proteins help diffusion go faster
FACILITATED DIFFUSION
NO energy required
• Passive = ____________________
HIGH  LOW
• Moves from ________________________
Carrier Proteins
• _____________________
bind molecule, change
shape, and release it on other side of membrane
Integral
(Carrier proteins are _______________
proteins)
• Molecules that move this way in cells:
GLUCOSE
_______________________
Facilitated Diffusion
Animation from: http://bio.winona.edu/berg/ANIMTNS/facdifan.gif
Kinds of Passive Transport
•
Diffusion
__________________________________
•Osmosis
•Facilitated
Diffusion
___________________________________
•Ion Channels
___________________________________
___________________________________
ION CHANNEL
ION CHANNELS
PASSIVE
• _____________transport
(no energy required)
HIGH  LOW
• Molecules move from ___________________
• Small passageways for _______
IONS to get through
membrane
• Each ion has own kind of passageway
• Examples in cells: Na+ , Cl- , Ca + + , K +
ION CHANNELS
Some channels always open
Some channels have “gates”
that open or close
in response to signals
SIGNALS:
•stretching of cell membrane
•electrical signals
•chemicals
Animation from: http://www2.uic.edu/~myilma1/ionchannel.gif
Kidspiration by: Riedell
Kinds of Active Transport
•________________________________________
Sodium-Potassium Pump
•Endocytosis
___________________________________
•Exocytosis
____________________________________
SODIUM-POTASSIUM PUMP
ATP
• ___________
ACTIVE transport (requires energy from ______)
• Special just for Na+ and K + ions
Carrier Proteins to move molecules
• Uses integral ___________________
• Examples in nerve cells:
Na+ is pumped out of cells at same time
K + is taken into cells
+
Na
and K
+
Animation from: http://www.lionden.com/cell_animations.htm
PUMP
ENDOCYTOSIS
Takes substances into cell
• _____________transport
(requires energy from ATP)
ACTIVE
• Uses small membrane sacs to carry substances
= VESICLES
______________
http://www.sirinet.net/~jgjohnso/cell.html
2 KINDS of ENDOCYTOSIS
Takes substances into cell
If taking in:
PINOCYTOSIS
fluid, molecules = ____________________
PHAGOCYTOSIS
large particles or whole cells = __________________
• Examples in cells:
– one celled organisms eat this way
– white blood cells get rid of bacteria this way
ENDOCYTOSIS
Animation from: http://academic.brooklyn.cuny.edu/biology/bio4fv/page/cell-movement.html
PHAGOCYTOSIS
White blood cell destroying germs
EXOCYTOSIS
Substances released outside of cell
ACTIVE transport (requires energy)
• __________
VESICLES
• Substances move in____________
• Examples in cells:
– Golgi release packaged proteins
Exocytosis
http://www.emc.maricopa.edu/faculty/farabee/BIOBK/BioBooktransp.html
GOLGI BODIES USE EXOCYTOSIS
Animation from: http://www.franklincollege.edu/bioweb/A&Pfiles/week04.html
Endocytosis & Exocytosis
http://grossmont.gcccd.cc.ca.us/cmilgrim/Bio120/Outline/
Outline2.gif/TransportMedia/EndoExocytosisMovie.htm