Cell Membrane & THE WAYS MOLECULES MOVE Chapter 7-3 Cellular Membrane & Transport (Ch. 7-3) Cell Membrane & THE WAYS MOLECULES MOVE Chapter 7-3 Cellular Membrane & Transport (Ch. 7-3)

Cellular Membrane & Transport (Ch. 7-3) Cell Membrane 1) POLAR ends face INSIDE & OUTSIDE cell (where water is…Hydrophilic) 2) NONPOLAR tails face each other inside bilayer (to avoid water…Hydrophobic) Cellular Membrane & Transport (Ch. 7-3) 2

Cellular Membrane & Transport (Ch. 7-3) Outside of cell Inside (cytoplasm) Cell membrane Proteins Protein channel Lipid bilayer Carbohydrate chains Cellular Membrane & Transport (Ch. 7-3) Cellular Membrane & Transport (Ch. 7-3) 3 3

Cellular Membrane & Transport (Ch. 7-3) 4 4

Cellular Membrane & Transport (Ch. 7-3) 3) FUNCTION: SELECTIVE PERMEABILITY = allows only certain materials to go into & out of cell Cellular Membrane & Transport (Ch. 7-3) 5 5

Cellular Membrane & Transport (Ch. 7-3) * Why doesn’t the cell membrane let everything through? HOMEOSTASIS! - Cells maintain a stable environment by controlling what enters & leaves. Cellular Membrane & Transport (Ch. 7-3) 6

Diffusion

FROM A LOT to NOT Molecules move _______“where there’s _______”

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 _______ the concentration gradient _______ an area of _______ concentration ____ an area of ________ concentration EXAMPLES DOWN from Higher to Lower Blue dye in beaker demo, Someone making popcorn/grilling out Strong perfume, Bad smell in room

DIFFUSION across a space Diffusion continues until the concentration is ________________ in space = ________________________ equal everywhere Equilibrium

Molecules need to move across membranes in cells

Diffusion can happen ________ a _____________ in a cell, too across membrane …as long as membrane will let the molecule _________________ pass through

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)

PROBLEM for CELLS? Diffusion only moves molecules from high concentration to low concentration.

What if cell needs to move a molecule _________ the CONCENTRATION GRADIENT? _______________ AGAINST (LOWER  HIGHER) Cell example: Want to put MORE glucose into mitochondria when there is already glucose in there

PROBLEM for Cells? Cell membranes are SELECTIVELY PERMEABLE See a movie

What if a cell needs to move _____ or ______ molecules that can’t get through the membrane? LARGE POLAR

PROBLEM for CELLS? Diffusion happens very slowly

What if cell needs to move molecules really _______ What if cell needs to move molecules really _______? (can’t wait for it to diffuse) FAST Cell example: Movement of Na + & K+ ions required to send nerve signals

Cells need a ____ to ____ molecules across cell membranes that _______ across by ___________ WAY HELP can’t go themselves

Kinds of ________ Transport PASSIVE __________________________________ ___________________________________ _______________________________ Diffusion Facilitated Diffusion Carriers Channels

DIFFUSION across a membrane DIFFERENCE Happens anytime there is a __________ in _____________ on one side of the membrane compared to the other concentration See diffusion animation

DIFFUSION PASSIVE DOWN HIGHER to LOWER OXYGEN Carbon dioxide No energy required = _______ Moves _______ concentration gradient from ___________________ Works for any molecules that can pass through the membrane Example of molecules that move this way in cells: ________ & ____________ DOWN HIGHER to LOWER OXYGEN Carbon dioxide

FACILITATED DIFFUSION uses _______________ to help molecules across 2 kinds of proteins help: _________ & ____________ membrane proteins Carriers Channels

Facilitated Diffusion with CARRIER PROTEINS grabs molecule, changes shape, and flips across to other side like a revolving door

FACILITATED DIFFUSION with CHANNELS Membrane proteins create a tunnel through which molecules can pass ION CHANNELS charged _______________ allow________ ions to get past the ____________ center hydrophobic

FACILITATED DIFFUSION with CHANNELS polar ________ proteins allow ________ _________ molecules to get past the __________ middle of cell membrane. Aquaporin WATER hydrophobic

FACILITATED DIFFUSION with CHANNELS The movement of water molecules across a cell membrane is called ______________ OSMOSIS

ALL KINDS OF FACILITATED DIFFUSION PASSIVE No energy required = _____________ Moves ________ concentration gradient from ________________________ ___________________ help molecules get across membrane DOWN HIGHER to LOWER Membrane proteins

EXAMPLES OF FACILITATED DIFFUSION IN CELLS CARRIER PROTEINS ION CHANNELS AQUAPORINS (OSMOSIS) GLUCOSE Na+ , Cl- , Ca++ , K+ WATER

Kinds of ________Transport ACTIVE ________________________________________ __________________________________ ________________________________ ___________________________________ PUMPS Sodium-Potassium Proton Vesicles Endocytosis Exocytosis

Na+ and K + PUMP See a movie about Na+ - K+ pump

SODIUM-POTASSIUM PUMP ACTIVE ___________ transport (requires energy from ______) Can move molecules from _____ concentration to ______ Special just for Na+ and K + ions Uses _______________________ called ____________ to move molecules Example: nerve cells Na+ is pumped out of cells at same time K + is taken into cells ATP low high membrane proteins pumps

PROTON PUMP H+ Moves Protons across membrane = ___ ions See a movie proton pump More on this in Chap 8 & 9

PROTON PUMP ACTIVE ATP low high Protein pumps ___________ transport (requires energy from ______) Can move molecules from _____ concentration to ________ Special just for H+ ions Uses integral ________________ to move molecules Examples: Lysosomes need acidic conditions for digestion Photosynthesis/Respiration (more on this to come in Ch 8 & 9) ATP low high Protein pumps

ACTIVE TRANSPORT with VESICLES ___________ are small membrane sacs that pinch off of cell membranes used by cells for transporting molecules Used for transporting molecules: If entering the cell = ______________ If exiting the cell = _______________ ENDOCYTOSIS EXOCYTOSIS

2 KINDS of ENDOCYTOSIS for taking substances into cell If taking in: fluid or small molecules =_________________ large particles or whole cells =______________ PINOCYTOSIS PHAGOCYTOSIS Animation from: http://academic.brooklyn.cuny.edu/biology/bio4fv/page/endocytb.htm

ENDOCYTOSIS Substances taken into cell ACTIVE energy __________ transport (requires________) Uses ______________ to carry substances Can move molecules from _____ concentration to ______ Examples in cells: one celled organisms eat this way white blood cells get rid of bacteria this way VESICLES low high

ENDOCYTOSIS Protist eating another

PHAGOCYTOSIS White blood cell germs ___________ destroying _______

WHITE BLOOD CELL ENGULFING BACTERIA (Phagocytosis)

EXOCYTOSIS Substances released outside of cell ACTIVE energy __________ transport (requires________) Uses ______________ to carry substances Can move molecules from _____ concentration to ______ Examples in cells: _________ release packaged proteins this way VESICLES low high GOLGI

GOLGI BODIES USE EXOCYTOSIS See a Golgi movie

INSULIN being released by pancreas cells using exocytosis

VOCAB _____________ = substance that is dissolved in a solvent to make a solution _____________ = substance in which a solute is dissolved SOLUTE SOLVENT

__________________ = mass of a solute in a given volume of solution CONCENTRATION MORE The _______ molecules there are in a given volume the ____________the concentration GREATER

Use new vocab to make Koolaid Koolaid powder sugar Solutes = ______________& __________ Solvent = ____________ Koolaid drink = ______________ Water solution

What if there is a difference in concentration but solute molecules can’t move across a membrane? WATER will move until concentration reaches equilibrium

 See an animation Osmosis1

What will happen to an animal cell placed in different solutions? Solute concentration Greater outside than inside Lower outside than inside Equal outside and inside HYPERTONIC HYPOTONIC ISOTONIC What will happen to an animal cell placed in different solutions?

Cells try to “maintain stable internal conditions = Remember: Cells try to “maintain stable internal conditions = ____________________ HOMEOSTASIS So an animal cell in ISOTONIC conditions stays same size Water entering = water leaving Video Choose Blood Isotonic link

If cells can’t maintain “stable internal conditions” . . . damage can result and cells can die.

OSMOSIS swell and possibly burst Video LESS THAN See an animation Osmosis3 Video Choose Blood Hypotonic link HYPOTONIC: Concentration outside cell is ________________ inside the cell More water enters than leaves cell so cell will ___________________ LESS THAN swell and possibly burst

OSMOSIS shrinks GREATER THAN Video See an animation OSMOSIS 4 HYPERTONIC: Concentration outside cell is ____________________ inside cell More water leaves cell than enters so cell ____________ GREATER THAN shrinks Choose Blood Hypertonic link Video

Animal cells _________ __________ = CYTOLYSIS = CRENATION

Plant cells _____ keeps ___________ = PLASMOLYSIS CELL WALL plant cells from bursting = PLASMOLYSIS CELL WALL

VACUOLES store WATER OSMOTIC PRESSURE _____________________________ = _____________________________ = Pressure exerted by the movement of water during osmosis

SO WHAT? hypotonic Bath water is ________________ compared to you Sitting in the bathtub causes your fingers and toes to wrinkle up when water ________ your skin cells by osmosis enters

Grocery stores spray water on their veggies to “plump them up”