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Designed by Pyeongsug Kim ©2010 [email protected]
Supplemental instruction
Cells and Their EnvironmentsCells and Their Environments
Picture from http://www.dejacool.com/images/cell_membrane.gif
____________ random movement of molecules from region of high to low concentration.
Diffusion
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-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 membranePlasma membrane
-Selectively permeable (semipermeable)-(non-polar / polar) molecules diffuse through cell membrane
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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
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Bulk transport Bulk transport : Cells move large compounds across membrane with endo- and exocytosis.
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______________- 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
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DownDown concentration gradient (HL)
ATP (required/no required) (Passive/Active)
Against Against concentration gradient (LH)
ATP (required/no required) (Passive/Active)
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________________________: 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 Na+/K+ pump -ATP (required/no required)- ______ out and _____ in cell against gradients.3 Na+ 2 K+
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Na+/K+ pumpNa+/K+ pump
Na+/K+ pump Na+/K+ pump -ATP (required/no required)- ______ out and _____ in cell against gradients.3 Na+ 2 K+
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_________________ voltage across membrane due to only 1 ion whereelectrical and diffusion forces are equal and opposite.ie/ K+ =_______ , Na+ = _____
Equilibrium potential
-90mV 60mV
________________________-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+) .
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Secondary active transportSecondary 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
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QUESTION 2 (Cont’d)QUESTION 2 (Cont’d)
2-4. Determine what type of transport is. (e.g passive, active, 1o 2 o co- or counter transport…) in A, B, & C.
S: 0.5MS1: 0.3MS2: 0.8M
S: 0.3MS1: 0.6MS2: 0.5M
A B C
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____________ 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 soluteWater
_______________: force needed to stop osmosis. It is proportional tosolute concentration.Osmotic pressure
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_________ 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.
IsotonicHypertonic
Hypotonic
Cells in hypotonic solution______= The bursting of a cellLysis
Cells in hypertonic solution________ = The crinkled shape of a cell that has lost waterCrenated
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Common isotonic intravenous solutions used in hospitals:
- 0.9% Saline (NaCl) (“Normal saline”)- 5% Glucose (“5% dextrose”)- Ringer’s lactate
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___________________ = 1 mole of solute dissolved in 1L of solution
___________________= 1 mole of solute dissolved in 1 kg H2O.
___________________= total molarity of a solutionEx/ 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)
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QUESTION 3QUESTION 3Please, solve the problems without your note and textbook.
3-1. 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 osmB: 0.3 osmC: 0.7 osm
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