“You are what you eat” Knowing what you do about the cell membrane do you agree or disagree with this statement and why?

Cell Transport

Passive Transport Movement across a cell membrane that does not require energy from the cell

Concentration GREATER A measure of the amount of dissolved substance contained per unit of volume MORE The _______ molecules there are in a given volume the ____________the concentration GREATER

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

Concentration Gradient DIFFERENCE Anytime there is a __________ in concentration in one place compared to another

DIFFUSION Molecules move automatically (random motion) _______ the concentration gradient _______ an area of _______ concentration ____ an area of ________ concentration DOWN from Higher to Lower

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

Molecules and ions need to move across membranes in cells

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

DIFFUSION Concentration gradient between the inside and outside of the cell Small and/or nonpolar molecules (ex. O2, CO2, H2O) can diffuse across the membrane down the concentration gradient

DIFFUSION 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)

Facilitated Diffusion A type of passive transport It moves substances down their concentration gradient without using the cell’s energy Uses Carrier Proteins and Channels

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

Ion Channel A transport protein with a polar pore through which ions can pass

Ion Channel The inside of a typical cell is negatively charged with respect to the outside of the cell A positively charged ion outside the cell is more likely to diffuse into the cell

Osmosis The diffusion of water through a selectively permeable membrane Water molecules are small and diffuse through the cell membrane

Example: gargling with salt water Osmosis Example: gargling with salt water

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

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

Cells try to “maintain stable internal conditions =__________________ HOMEOSTASIS If cells can’t maintain “stable internal conditions” . . . damage can result and cells can die.

Solute concentration Greater outside than inside Lower outside Equal outside and inside HYPERTONIC HYPOTONIC ISOTONIC

OSMOSIS HYPOTONIC: Concentration outside cell is ________________ inside the cell More water enters than leaves cell so cell will ___________________ LESS THAN swell and possibly burst

OSMOSIS A cell in ISOTONIC conditions stays same size

OSMOSIS shrinks GREATER THAN HYPERTONIC: Concentration outside cell is ____________________ inside cell More water leaves cell than enters so cell ____________ GREATER THAN shrinks

What happens if a plant cell is placed in a hypotonic, isotonic, or hypertonic solution?

hypotonic Bath water is a _________ solution enters Sitting in the bathtub causes your fingers and toes to wrinkle up when water ________ your skin cells by osmosis enters

PROBLEM for CELLS? Diffusion only moves molecules from high concentration to low concentration Diffusion happens slowly Diffusion to some extent only works if substance can pass through cell membrane

PROBLEM for Cells? Cell membranes are SELECTIVELY PERMEABLE

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

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

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

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

Active Transport Transport of a substance across the cell membrane against its concentration gradient Requires the cell to use energy (comes directly or indirectly from ATP)

________________ and ___________ help molecules to cross cell membranes Membrane proteins vesicles

Active Transport Some active-transport processes involve carrier proteins Function as pumps

Sodium-Potassium Pump Pumps 3 sodium ions out of the cell and 2 potassium ions into the cell

PROTON PUMP Moves Protons across membrane = ___ ions H+

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 ATP low high Protein pumps

Vesicles Many substances are too large to be transported by carrier proteins Moved across the cell membrane by vesicles

Vesicles Endocytosis Movement of a substance into a cell by a vesicle Exocytosis Movement of substances by a vesicle to the outside of a cell

2 KINDS of ENDOCYTOSIS for taking substances into cell If taking in: fluid or small molecules =_________________ large particles or whole cells =______________ PINOCYTOSIS PHAGOCYTOSIS

PHAGOCYTOSIS White blood cell germs ___________ destroying _______

WHITE BLOOD CELL ENGULFING BACTERIA (Phagocytosis)

GOLGI BODIES USE EXOCYTOSIS

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

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

Review Video https://www.youtube.com/watch?v=prfMUwjobo8

Act It Out Passive Transport Active Transport Diffusion Facilitated Diffusion: Ion Channels Osmosis Active Transport Carrier Proteins/Protein Pumps (Na+/K+) Vesicles