Transcript CELL PARTS Chapter 4

The Plasma Membrane -
Gateway to the Cell
Photograph of a Cell
Membrane
Types of Transport
Across Cell Membranes
Simple Diffusion
• Requires NO
energy
• Molecules move
from area of
HIGH to LOW
concentration
DIFFUSION
Diffusion is a
PASSIVE process
which means no
energy is used to
make the molecules
move, they have a
natural KINETIC
ENERGY
Diffusion of Liquids
Diffusion through a Membrane
Cell membrane
Solute moves DOWN concentration gradient (HIGH to
LOW)
Osmosis
• Diffusion of water
across a membrane
• Moves from HIGH
water potential (low
solute) to LOW
water potential (high
solute)
Diffusion across a membrane
Semipermeable
membrane
Diffusion of H2O Across A
Membrane
High H2O potential
Low solute concentration
Low H2O potential
High solute concentration
Cell in Isotonic Solution
10% NaCL
90% H2O
ENVIRONMENT
CELL
10% NaCL
90% H2O
NO NET
MOVEMENT
What is the direction of water movement?
equilibrium
The cell is at _______________.
Cell in Hypotonic Solution
10% NaCL
90% H2O
CELL
20% NaCL
80% H2O
What is the direction of water movement?
Cell in Hypertonic Solution
15% NaCL
85% H2O
ENVIRONMENT
CELL
5% NaCL
95% H2O
What is the direction of water movement?
Cells in Solutions
Isotonic Solution
NO NET
MOVEMENT OF
H2O (equal amounts
entering & leaving)
Hypotonic
Solution
CYTOLYSIS
Hypertonic
Solution
PLASMOLYSIS
Cytolysis & Plasmolysis
Cytolysis
Plasmolysis
Osmosis in Red Blood Cells
Isotonic
Hypotonic
Hypertonic
hypotonic
hypertonic
isotonic
hypertonic
isotonic
hypotonic
Three Forms of Transport Across the Membrane
Passive Transport
Simple Diffusion
 Doesn’t require energy
 Moves high to low
concentration
 Example: Oxygen or
water diffusing into a
cell and carbon dioxide
diffusing out.
Passive Transport
Facilitated diffusion
Doesn’t require energy
Uses transport
proteins to move high to
low concentration
Examples: Glucose or
amino acids moving from
blood into a cell.
Proteins Are Critical to
Membrane Function
Active Transport
Requires energy or
ATP
Moves materials from
LOW to HIGH
concentration
AGAINST
concentration gradient
Active transport
Examples: Pumping
Na+ (sodium ions) out
and K+ (potassium
ions) in against
strong concentration
gradients.
Called Na+-K+ Pump
Sodium-Potassium Pump
3 Na+ pumped in for every 2 K+ pumped
out; creates a membrane potential
Moving the “Big Stuff”
Exocytosis
- moving
things
out.
Molecules are moved out of the cell by vesicles that fuse
with the plasma membrane.
This is how many hormones are secreted and how nerve
cells communicate with one another.
Exocytosis
Exocytic
vesicle
immediately
after fusion
with plasma
membrane.
Moving the “Big Stuff”
Large molecules move materials into the cell by
one of three forms of endocytosis.
Pinocytosis
Most common form of endocytosis.
Takes in dissolved molecules as a vesicle.
Pinocytosis
• Cell forms an
invagination
• Materials dissolve
in water to be
brought into cell
• Called “Cell
Drinking”
Example of Pinocytosis
pinocytic vesicles forming
mature transport vesicle
Transport across a capillary cell (blue).
Receptor-Mediated Endocytosis
Some integral proteins have receptors
on their surface to recognize & take in
hormones, cholesterol, etc.
Receptor-Mediated Endocytosis
Endocytosis – Phagocytosis
Used to engulf large particles such as
food, bacteria, etc. into vesicles
Called “Cell Eating”
Phagocytosis About to Occur
Phagocytosis
- Capture
of a Yeast
Cell (yellow)
by
Membrane
Extensions
of an
Immune
System Cell
(blue)
Exocytosis
The opposite of endocytosis is exocytosis. Large
molecules that are manufactured in the cell are
released through the cell membrane.
Inside Cell
Cell environment
OSMOSIS
http://www.biology4kids.com/files/cell_main.html
Diffusion
http://lhs.lps.org/staff/sputnam/Biology/U3Cell/diffusion_1.png
See a video clip about
DIFFUSION-7A
Animatioin from: http://www.biologycorner.com/resources/diffusion-animated.gif
Molecules move
FROM
A LOT
_______“where
there’s _______”
to
NOT
____“where
there’s _______”
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 _______
DOWN
the concentration gradient _______
an
from
area of _______
Higher concentration ____
to an
area of ________
concentration
Lower
• EXAMPLES
Blue dye in beaker demo,
Someone making popcorn/grilling out
Strong perfume,
Bad smell in room
http://leighhouse.typepad.com/blog/images/kool_aid.jpg
http://www.swapmeetdave.com/Humor/Farts.htm
DIFFUSION across a space
Diffusion continues until the concentration
equal everywhere
is ________________
in space
Equilibrium
= ________________________
http://lhs.lps.org/staff/sputnam/Biology/U3Cell/diffusion_1.png
Molecules
need to
move
across
membranes
in cells
Image modiified from: http://www.accessexcellence.org/AB/GG/importProt.html
across
Diffusion can happen ________
a
membrane
_____________
in a cell, too
…as long as membrane will let the molecule
pass through
_________________
Video from: http://www.southtexascollege.edu/tdehne/BC_ShockwaveAnimations/08SWF-MembraneStructureAndFunct/08-02-MembraneStructure.swf
SELECTIVELY
PERMEABLE
(Semi-permeable)
See a movie
http://life.nthu.edu.tw/~d857401/advance.html
CELL EXAMPLE:
DIFFUSION automatically moves oxygen
from HIGHER concentration (in lungs)
to a LOWER concentration (in blood)
CO2 automatically moves
from where there is a
HIGHER concentration
(in blood) to where there
is a lower concentration
(in lungs)
http://www.le.ac.uk/pa/teach/va/anatomy/case2/2_2.html
BUT….
What if a cell needs to
LARGE or ______
POLAR
move _____
molecules?
http://www.d.umn.edu/~sdowning/Membranes/membraneImages/jpegimages/diffusionmedium.jpg
What if cell needs to move a
AGAINST the
molecule _________
CONCENTRATION
GRADIENT?
_______________
(LOWER  HIGHER)
Cell example:
Want to put MORE glucose
into mitochondria when there is
already glucose in there
Image from: http://www.biologyclass.net/mitochondria.jpg
What if cell needs to move
FAST
molecules really _______?
(can’t wait for it to diffuse)
Cell example:
Movement of
Na + & K+ ions
required to send
nerve signals
http://www.steve.gb.com/images/science/neuron.png
WAY to ____
HELP
We need a ____
molecules across cell
can’t go
membranes that _______
themselves
across by ___________
Kidspiration by: Riedell
PASSIVE Transport
Kinds of ________
•__________________________________
Diffusion
•Osmosis
___________________________________
•Facilitated
Diffusion
___________________________________
DIFFUSION across a membrane
DIFFERENCE
Happens anytime there is a __________
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
See diffusion
animation
OSMOSIS
= SPECIAL KIND OF DIFFUSION
IMAGE by RIEDELL
OSMOSIS
____________
See osmosis
animation
DIFFUSION
__________
Movement of molecules across a
Semi-permeable membrane
_________________
lower
from ______
Higher concentration to _____
See a video about Passive transport 7-C
Facilitated Diffusion
Carrier proteins help diffusion go faster
_______
FACILITATED DIFFUSION
• No energy required = __________________
PASSIVE
DOWN concentration gradient
• Moves _________
from ________________________
HIGHER to LOWER
Membrane proteins
• _____________________
grab molecule,
change shape, and flip to other side
(Like a revolving door)
• Molecules that move this way in cells:
GLUCOSE
_______________________
Facilitated Diffusion
Animation from: http://bio.winona.edu/berg/ANIMTNS/facdifan.gif
Kidspiration by: Riedell
ACTIVE
Kinds of ________Transport
•________________________________________
Sodium-Potassium Pump
•Endocytosis
___________________________________
____________________________________
•Exocytosis
See a video clip about
Na+-K+ pump -7D
Sodium (Na+)- Potassium (K+)
Pump
Animation from: http://www.lionden.com/cell_animations.htm
See a movie
about Na+ - K+ pump
Sodium-Potassium pump
• ___________
transport
ACTIVE
(requires energy from ______)
ATP
• Special just for Na+ and K
+
ions
Carrier Proteins
• Uses integral ___________________
to move
molecules
• Examples in nerve cells:
Na+ is pumped out of cells at same time
K + is taken into cells
See a video clip about
Endo/exocytosis -7E
ENDOCYTOSIS
Takes substances into cell
ACTIVE
• _____________transport
energy from ______)
ATP
(requires __________
• Uses small membrane sacs called
______________
to carry substances
VESICLES
http://www.sirinet.net/~jgjohnso/cell.html
2 KINDS of ENDOCYTOSIS
Takes substances into cell
If taking in:
PINOCYTOSIS
fluid or small 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
Pinocytosis
• Called “Cell Drinking”
ENDOCYTOSIS
Animation from: http://academic.brooklyn.cuny.edu/biology/bio4fv/page/cell-movement.html
http://www.accs.net/users/kriel/chapter%20nine/
PHAGOCYTOSIS
Called “Cell
Eating”
White
blood cell
___________
germs
destroying _______
EXOCYTOSIS
Substances released outside of cell
ACTIVE transport
• __________
energy
(requires __________)
VESICLES
• Substances move in____________
• Examples in cells:
– _________
release packaged proteins
GOLGI
this way
Exocytosis
http://www.emc.maricopa.edu/faculty/farabee/BIOBK/BioBooktransp.html
Video: http://www.southtexascollege.edu/tdehne/BC_ShockwaveAnimations/07SWF-TourOfTheCell/07-16-EndomembraneSystem.swf
GOLGI BODIES USE EXOCYTOSIS
Animation from: http://www.franklincollege.edu/bioweb/A&Pfiles/week04.html
See a Golgi movie
Videos from:
http://www.pleasanton.k12.ca.us/avhsweb/thiel/apbio/notes/chp8/exocytosis_endocytosis.mov
http://trc.ucdavis.edu/biosci10v/bis10v/week2/endocytosis.mov
Endocytosis & Exocytosis
Watch a video clip about endo/exocytosis
Watch a video clip about endo/exocytosis
Choose Screen/Switch programs to view
INSULIN being released by
pancreas cells using exocytosis
http://fig.cox.miami.edu/~cmallery/255/255ion/fig14x26.jpg
What if there is a difference in
concentration but solute
molecules can’t move across a
membrane?
WATER will move
until concentration
reaches equilibrium
VOCAB
_____________
SOLUTE
= substance that is
dissolved in a solvent to make a solution
SOLVENT = substance in which a
_____________
solute is dissolved
EX:
Koolaid powder = solute
Water = solvent
Koolaid drink = solution
http://www.makash.ac.il/h_school/hst/hstsb/chem/luach/dissolve.jpg
Images by Riedell
__________________
CONCENTRATION = mass of
a solute in a given volume of
solution
MORE molecules there are in a given
The _______
volume the ____________the
concentration
GREATER
See a video clip about
OSMOSIS -7B
Animation: http://www.ouhscphysio.org/humanphys/animations/osmosis1.swf
See an animation
Osmosis1
http://faculty.etsu.edu/currie/images/osmosis1.jpg
Animation from: http://www.ouhscphysio.org/humanphys/animations/osmosis4.swf
OSMOSIS
See an animation
OSMOSIS 4
HYPERTONIC: Concentration outside cell is
____________________
inside cell
GREATER THAN
More water leaves cell than enters
so cell ____________
shrinks
Cell in Hypertonic Solution
15% NaCL
85% H2O
ENVIRONMENT
CELL
5% NaCL
95% H2O
What is the direction of water movement?
Animation from: http://www.ouhscphysio.org/humanphys/animations/osmosis3.swf
OSMOSIS
See an animation
Osmosis3
HYPOTONIC:
Concentration outside cell is
________________
LESS THAN inside the cell
More water enters than leaves cell so cell
will ___________________
Swell and possibly burst
Cell in Hypotonic Solution
10% NaCL
90% H2O
CELL
20% NaCL
80% H2O
What is the direction of water movement?
OSMOSIS
ISOTONIC:
EQUALS
Concentration outside cell __________
concentration inside cell
Water entering = water leaving
STAYS THE SAME SIZE
so cell _____________________
Cell in Isotonic Solution
10% NaCL
90% H2O
ENVIRONMENT
CELL
10% NaCL
90% H2O
NO NET
MOVEMENT
What is the direction of water movement?
equilibrium
The cell is at _______________.
Isotonic Solution
NO NET
MOVEMENT OF
H2O (equal amounts
entering & leaving)
Hypotonic
Solution
Cell Swells &
may burst
Hypertonic
Solution
Cell shrivels up
Animal cells
http://www.stchs.org/science/courses/sbioa/metenergy/bloodcells.gif
Osmosis in Red Blood Cells
Isotonic
Hypotonic
Hypertonic
http://www.stchs.org/science/courses/sbioa/metenergy/aplantturgor.gif
Plant cells
CELL WALL
_____
keeps
Plant cells from bursting
VACUOLES store WATER
http://www.biology4kids.com/files/cell_vacuole.html
OSMOTIC PRESSURE
_____________________________
=
Pressure exerted by water during osmosis
SO WHAT?
Bath water is
________________
hypotonic
compared to you
Sitting in the bathtub causes your fingers
and toes to wrinkle up when water
________
enters your skin cells by osmosis
Grocery stores spray water on
their veggies to “plump them up”
http://www.painetworks.com/photos/gt/gt0461.JPG
SO WHAT?