Transporting Molecules

CELL MEMBRANE (also called plasma membrane) Cell membranes are made of ________________ & __________________ PHOSPHOLIPIDS PROTEINS

CELL MEMBRANE Proteins that stick on the surface = PERIPHERAL (either inside or outside of cell) Proteins that stick INTO membrane = INTEGRAL (can go part way in or all the way through)

Recognize “self” GLYCOPROTEINS GLYCOPROTEINS are INTEGRAL PROTEINS

SELECTIVELY PERMEABLE (semi-permeable)

Diffusion

Molecules move from “where there’s A LOT” to “where there’s NOT” Animatioin from:

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: _____________________ _____________________ Higher Lower Perfume, Koolaid, popcorn, BBQ, Bad smell in room

Molecules need to move across membranes in cells Image modiified from:

Diffusion can happen across a membrane in a cell …as long as membrane will let molecule through

SELECTIVELY PERMEABLE

happens by DIFFUSION from HIGHER concentration to LOWER concentration Image modified from: Gas exchange between lungs and blood

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? Example : Glucose into mitochondria (LOW  HIGH) Image from:

What if cell needs to move molecules really FAST? (can’t wait for it to diffuse) Example in cells: Movement of ______________ ions sends nerve signals Na + & K +

2 KINDS of TRANSPORT across cell membranes ____________TRANSPORT Does NOT require energy ___________TRANSPORT Requires energy PASSIVE ACTIVE

Kidspiration by: Riedell

Kinds of Passive Transport Diffusion Osmosis Facilitated Diffusion Ion Channels __________________________________ ___________________________________

DIFFUSION across a membrane Happens anytime there is a __________ in concentration on one side of the membrane compared to the other DIFFERENCE Molecules that move by diffusion across membranes in cells: ______________ OXYGEN CARBON DIOXIDE

OSMOSIS MOVES WATER MOLECULES Across a MEMBRANE From HIGHER  LOWER = SPECIAL KIND OF DIFFUSION

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

Kinds of Passive Transport Diffusion Osmosis Facilitated Diffusion Ion Channels __________________________________ ___________________________________

Facilitated Diffusion Carrier 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:

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: 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:

ENDOCYTOSIS Takes substances into cell _____________transport (requires energy from ATP) Uses small membrane sacs to carry substances ______________ ACTIVE = VESICLES

2 KINDS of ENDOCYTOSIS Takes 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

ENDOCYTOSIS Animation from:

PHAGOCYTOSIS White blood cell destroying germs

EXOCYTOSIS Substances released outside of cell __________ transport (requires energy) Substances move in____________ Examples in cells: –Golgi release packaged proteins ACTIVE VESICLES

Exocytosis

GOLGI BODIES USE EXOCYTOSIS Animation from:

Endocytosis & Exocytosis Outline2.gif/TransportMedia/EndoExocytosisMovie.htm