Transporting Molecules

Diffusion

http://lhs.lps.org/staff/sputnam/Biology/U3Cell/diffusion_1.png

Molecules move

from “where there’s A LOT”

to “where there’s NOT”

Animatioin from: http://www.biologycorner.com/resources/diffusion-animated.gif

DIFFUSION across a space

Happens anytime there is a _____________ in concentration in one place compared to another

(________________________)

DIFFERENCE

= Concentration gradient

DIFFUSION across a space

• Molecules move automatically from an area of _______ concentration to an area of ________ concentration

• EX: _____________________ _____________________

HigherLower

Perfume, Koolaid, popcorn,BBQ, Bad smell in room

http://www.swapmeetdave.com/Humor/Farts.htmhttp://leighhouse.typepad.com/blog/images/kool_aid.jpg

Molecules need to

move across membranes

in cells

Image modiified from: http://www.accessexcellence.org/AB/GG/importProt.html

If there is a difference in concentration on two sides of a membrane…Diffusion can happen ACROSS A MEMBRANE too!

…as long as membrane will let molecule through

SELECTIVELY PERMEABLE

DIFFUSION moves them from HIGHER (lungs) concentration to LOWER concentration (blood)

Image modified from: http://www.medaille.edu/vmacer/120_graphic_05oxygen.gif

EXAMPLE: Oxygen molecules move automaticallyfrom lungs into blood

What if cell needs to move large or polar molecules?

EX:

GlucoseAmino acids

What if cell needs to move a molecule AGAINST the CONCENTRATION GRADIENT?

Example :

Glucose into mitochondria

(LOW HIGH)

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

WAYS MOLECULES MOVE ACROSS MEMBRANES

• PASSIVE TRANSPORT Does NOT require energy

• ACTIVE TRANSPORTRequires energy

Kidspiration by: Riedell

Kinds of Passive Transport

• Diffusion

•Osmosis•Facilitated Diffusion•Ion Channels

__________________________________

___________________________________

___________________________________

___________________________________

DIFFUSION across a membrane• Moves from:

HIGHER concentration LOWER

Any kind of molecule that can pass through the membrane can do this. EX: ______________ ______________

OXYGEN

CARBON DIOXIDE

http://www.lionden.com/cell_animations.htm

OSMOSIS

• MOVES WATER

MOLECULES

• Across a SEMI-PERMEABLE MEMBRANE

• Moves from HIGHER LOWER

http://www.Isbu.ac.uk/water/molecule.html

What if there is a difference in concentration but solute molecules

can’t move across a membrane?

WATER will move until concentrationreaches equilibrium

http://www.sidwell.edu/us/science/vlb6/labs/a_osmosis.gif

 Osmosis1

OSMOSIS

HYPERTONIC: Concentration outside cell is ____________________ inside cell

More water leaves cell than enters so cell ____________

GREATER THAN

shrinks

Osmosis4

OSMOSIS

HYPOTONIC: Concentration outside cell is ________________ inside the cell

More water enters than leaves cell so cellwill ___________________

LESS THAN

Swell bigger

Osmosis3

OSMOSIS

ISOTONIC:

Concentration outside cell ____________

concentration inside cell

Water entering = water leavingso cell _____________________

EQUALS

STAYS THE SAME SIZE

Animal cells

= cytolysishttp://www.stchs.org/science/courses/sbioa/metenergy/bloodcells.gif

= crenation

Plant cells

= Plasmolysis

http://www.stchs.org/science/courses/sbioa/metenergy/aplantturgor.gif

No cytolysis/cell wall keeps it from bursting

VACUOLES store WATER

http://www.biology4kids.com/files/cell_vacuole.html

_______________________ =Pressure of water molecules pushing against cell wall

TURGOR PRESSURE

SO WHAT?

SO WHAT?

Sitting in the bathtub causes your fingers and toes to wrinkle up when water enters your skin cells by osmosis

Bath water is HYPOTONICcompared to you

Kinds of Passive Transport

• Diffusion

•Osmosis•Facilitated Diffusion•Ion Channels

__________________________________

___________________________________

___________________________________

___________________________________

Facilitated DiffusionCarrier proteins help diffusion go faster

FACILITATED DIFFUSION• Passive = ____________________

• Moves from ________________________

• _____________________ bind molecule, change shape, and release it on other side of membrane

(Carrier proteins are _______________ proteins)

• Molecules that move this way in cells:_______________________

NO energy required

Carrier Proteins

Integral

GLUCOSE

HIGH LOW

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• _____________transport (no energy required)

• Molecules move from ___________________

• Small passageways for _______ to get through membrane

• Each ion has own kind of passageway

• Examples in cells: Na+ , Cl- , Ca + + , K +

PASSIVE

HIGH LOW

IONS

ION CHANNELS

Some channels always open

Some channels have “gates”

that open or close

in response to signals

Animation from: http://www2.uic.edu/~myilma1/ionchannel.gif

SIGNALS:•stretching of cell membrane•electrical signals•chemicals

Kidspiration by: Riedell

Kinds of Active Transport

• Sodium-Potassium Pump•Endocytosis

•Exocytosis

________________________________________

___________________________________

____________________________________

SODIUM-POTASSIUM PUMP

• ___________ transport (requires energy from ______)

• Special just for Na+ and K + ions

• Uses integral ___________________ to move molecules

• Examples in nerve cells: Na+ is pumped out of cells at same time K + is taken into cells

ACTIVE

Carrier Proteins

ATP

Na+ and K + PUMP

Animation from: http://www.lionden.com/cell_animations.htm

ENDOCYTOSISTakes substances into cell

• _____________transport (requires energy from ATP)

• Uses small membrane sacs to carry substances

______________

ACTIVE

= VESICLES

http://www.sirinet.net/~jgjohnso/cell.html

2 KINDS of ENDOCYTOSISTakes substances into cell

If taking in:

fluid, molecules = ____________________

large particles or whole cells = __________________

• Examples in cells:– one celled organisms eat this way– white blood cells get rid of bacteria this way

PINOCYTOSIS

PHAGOCYTOSIS

ENDOCYTOSISAnimation from: http://academic.brooklyn.cuny.edu/biology/bio4fv/page/cell-movement.html

http://www.accs.net/users/kriel/chapter%20nine/

PHAGOCYTOSIS

White blood cell destroying germs

EXOCYTOSISSubstances released outside of cell

• __________ transport (requires energy)

• Substances move in____________

• Examples in cells:

– Golgi release packaged proteins

ACTIVE

VESICLES

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