Designed by Pyeongsug Kim ©2010 Supplemental instruction Cells and Their Environments Picture from

____________ random movement of molecules from region of high to low concentration. Diffusion Designed by Pyeongsug Kim, ©2010

-block most solutes from diffusing -Hydrophilic solutes (can/cannot) pass through -Hydrophophic solutes (can/cannot) pass through Why? Hydrophilic solutes do not mix with the hydrophobic phospholipids of the cell membrane. Hydrophobic will mix with the hydrophobic phospholipids of the cell membrane. Plasma membrane -Selectively permeable (semipermeable) -(non-polar / polar) molecules diffuse through cell membrane Designed by Pyeongsug Kim, ©2010

1) 2) 3) Simple diffusion (only hydrphobic) By endocytosis and exocytosis Through membrane transport proteins How molecules can cross cell membranes? e.g Steroid hormones, O2, CO2 Highly specific to transport only the solute Designed by Pyeongsug Kim, ©2010

Bulk transport : Cells move large compounds across membrane with endo- and exocytosis. Designed by Pyeongsug Kim, ©2010

______________ - brings solute molecules into a cell by the membrane bending inward, followed by the bend pinching off from membrane -form a ______ inside the cell Endocytosis vesicle _______________ -brings solute molecules out of a cell by the molecules moving into a ________ in the cell inward followed by the vesicle fusing with the cell membrane Exocytosis vesicle Designed by Pyeongsug Kim, ©2010

Down Down concentration gradient (H  L) ATP (required/no required)  (Passive/Active) Against Against concentration gradient (L  H) ATP (required/no required)  (Passive/Active) Designed by Pyeongsug Kim, ©2010

________________________: molecules too large and polar to diffuse across membrane are transported by proteins. Carrier-mediated transport ________________ -(passive/active) transport down concentration gradient w/carrier proteins. -ATP (required/no required) Facilitated diffusion ______________: transport of molecules from (high/low) concentration to (high/low) concentration. Active transport Na+/K+ pump -ATP (required/no required) - ______ out and _____ in cell against gradients. 3 Na+2 K+ Designed by Pyeongsug Kim, ©2010

Designed by Pyeongsug Kim, ©2010

Na+/K+ pump -ATP (required/no required) - ______ out and _____ in cell against gradients. 3 Na+2 K+ Designed by Pyeongsug Kim, ©2010

_________________ voltage across membrane due to only 1 ion where electrical and diffusion forces are equal and opposite. ie/ K+ =_______, Na+ = _____ Equilibrium potential -90mV60mV ________________________ -Not producing impulses, -Around _______ -K+ drives most of RMP because it is quite permeable. Resting membrane potential (RMP) -70mV Cell membrane is more pearmeable ( K+ than Na+ / Na+ than K+). Designed by Pyeongsug Kim, ©2010

Secondary active transport -ATP moves Na+ to create gradient, Na+ moves downhill to bring in another molecule. ____________ = same direction as Na+. _____________= opposite direction of Na+. Cotransport Countertransport Cotransport Designed by Pyeongsug Kim, ©2010

QUESTION 2 (Cont’d) 2-4. Determine what type of transport is. (e.g passive, active, 1 o 2 o co- or counter transport…) in A, B, & C. S: 0.5M S1: 0.3M S2: 0.8M S: 0.3M S1: 0.6M S2: 0.5M A B C Designed by Pyeongsug Kim, ©2010

____________ random movement of molecules from region of high to low concentration. Diffusion ___________ net diffusion of H2O across selectively permeable membrane. Osmosis Water diffuses until concentration is equal on both sides of membrane. __________ : water channels to facilitate osmosis. Aquaporins Less solute High solute Water _______________: force needed to stop osmosis. It is proportional to solute concentration. Osmotic pressure Designed by Pyeongsug Kim, ©2010

_________ effect of solution of osmotic water movement.Tonicity ___________ solutions with same osmotic pressure. ___________solutions with higher osmotic pressure than cell that are osmotically active. ___________ lower osmotic pressure. Isotonic Hypertonic Hypotonic Cells in hypotonic solution ______ = The bursting of a cell Lysis Cells in hypertonic solution ________ = The crinkled shape of a cell that has lost water Crenated Designed by Pyeongsug Kim, ©2010

Common isotonic intravenous solutions used in hospitals: - 0.9% Saline (NaCl) (“Normal saline”) - 5% Glucose (“5% dextrose”) - Ringer’s lactate Designed by Pyeongsug Kim, ©2010

___________________ = 1 mole of solute dissolved in 1L of solution ___________________= 1 mole of solute dissolved in 1 kg H2O. ___________________= total molarity of a solution Ex/ 1.0m of NaCl = 2 Osm solution (NaCL dissociates into Na+ and Cl-) 1 molar solution (1.0M) 1 molal solution (1.0m) Osmolarity (Osm) Designed by Pyeongsug Kim, ©2010

QUESTION 3 Please, solve the problems without your note and textbook There are three type of solution regarding tonicity. What are they? What happen when cells are in each solution? 3-2. Where is most fluid in our body? The interstitial fluid comprises what percentage of the extracellular fluid? 3-3. What will the cell happen in the picture below? A: 0.3 osm(penetrating) B: 0.8 osm A: 0.3 osm B: 0.3 osm C: 0.7 osm Designed by Pyeongsug Kim, ©2010