Term
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Definition
| the fluid concentrations are equal on the two sides of the cell membrane; comes from water having free movement from the extracellular & intracellular compartments |
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Term
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Definition
| when a solute is more concentrated in one of the two body compartments than the other |
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Term
| electrical disequilibrium |
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Definition
| the ionic imbalance between the ICF and ECF; ICF is more negative & ECF is more positive |
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Term
| What is the total body water of the standard man? |
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Definition
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Term
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Definition
| the movement of water across a membrane in response to a solute concentration gradient |
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Term
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Definition
| a force applied to exactly oppose osmosis |
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Term
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Definition
| the number of osmotically active particles per liter of solution; how biological solutions express concentration |
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Term
| equation to convert from molarity to osmolarity |
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Definition
| molarity (mol/L) x particles/molecule (osmol/mol) = osmolarity (osmol/L) |
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Term
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Definition
| concentration expressed as osmoles of solute per kilogram of water |
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Term
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Definition
| two solutions that contain the same number of solute particles per unit volume |
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Term
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Definition
| a solution that has a higher osmolarity than another solution |
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Term
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Definition
| a solution that has a lower osmolarity than another solution |
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Term
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Definition
| a term used to describe a solution & how that solution would affect cell volume if the cell were placed in the solution & allowed to come to equilibrium |
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Term
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Definition
| a solution that would cause a cell to gain water & swell |
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Term
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Definition
| a solution that would cause a cell to lose water & shrink |
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Term
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Definition
| a solution that would not cause a cell to change size |
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Term
| Osmolarity VS Tonicity: which has units? |
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Definition
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Term
| Osmolarity VS Tonicity: which compares a solution to a cell? which compares a solution to a solution? |
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Definition
osmolarity = solution to solution
tonicity = solution to cell |
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Term
| Osmolarity VS Tonicity: which tells you what would happen to a cell in a solution? |
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Definition
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Term
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Definition
| solute particles that can enter the cell |
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Term
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Definition
| particles that cannot cross the cell membrane |
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Term
| If the cell has a higher concentration of nonpenetrating solutes than the solution, the solution is _____ |
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Definition
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Term
| If the cell has a lower concentration of nonpenetrating solutes than the solution, the solution is _____ |
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Definition
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Term
| If the concentration of nonpenetrating solutes are the same in the cell & the solution, the solution is _____ |
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Definition
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Term
| What is the most general form of biological transport of fluids within a body compartment? |
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Definition
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Term
| Are liquids the only substance considered fluids? |
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Definition
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Term
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Definition
| some molecules can cross the cell membrane but others cannot |
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Term
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Definition
| a membrane that allows a substance to pass through it |
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Term
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Definition
| a membrane that does not allow a substance to pass |
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Term
| What type of movement of molecules does not require the input of energy other than the potential energy stored in a concentration gradient? |
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Definition
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Term
| What type of movement of particles requires the input of energy from some outside source such as the high-energy phosphate bond of ATP? |
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Definition
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Term
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Definition
| the movement of molecules from an area of higher concentration of the molecules to an area of lower concentration of the molecules |
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Term
| Is diffusion an active or passive process? |
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Definition
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Term
| In what direction to molecules move in diffusion? |
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Definition
| from high concentration to low concentration |
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Term
| concentration gradient (AKA chemical gradient) |
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Definition
| a difference in the concentration of a substance between two places |
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Term
| When does the net movement of diffusion stop? |
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Definition
| when the concentration is equal everywhere |
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Term
| Is diffusion faster over short distances or long distances? |
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Definition
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Term
| Is diffusion directly related to temperature? |
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Definition
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Term
| Is diffusion positively or inversely related to molecular weight & size? |
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Definition
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Term
| Does diffusion always have to take place in an open system? |
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Definition
| no! (it can also take place across a partition that separates two compartments) |
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Term
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Definition
| diffusion directly across the phospholipid bilayer of a membrane |
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Term
| What does the rate of simple diffusion depend on? |
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Definition
| the ability of the diffusing molecule to dissolve in the lipid bilayer of the membrane |
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Term
| To what is the rate of simple diffusion directly proportional? |
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Definition
| the surface area of the membrane |
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Term
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Definition
| the diffusion rate increases when the surface area, the concentration gradient, or the membrane permeability increases |
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Term
| As molecular size increases, membrane permeability _____ |
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Definition
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Term
| As lipid solubility of the diffusing molecule increases, membrane permeability to the molecule _____ |
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Definition
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Term
| Does cholesterol in a membrane increase or decrease permeability? |
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Definition
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Term
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Definition
| diffusion rate / surface area = concentration gradient x membrane permeability |
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Term
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Definition
| diffusion rate per unit surface area of membrane (concentration gradient x membrane permeability) (diffusion rate / surface area) |
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Term
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Definition
| when membrane proteins help solutes cross membranes; the vast majority of solutes permeate this way |
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Term
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Definition
| when mediated transport is passive & moves molecules down their concentration gradient & net transport stops when concentrations are equal on both sides of the membrane |
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Term
| 4 broad categories of membrane proteins |
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Definition
1. structural proteins
2. enzymes
3. receptors
4. transport proteins |
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Term
| 3 major roles of structural proteins |
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Definition
1. help create cell junctions that hold tissues together, such as tight junctions & gap junctions
2. connect the membrane to the cytoskeleton to maintain the shape of the cell
3. attach cells to the extracellular matrix by linking cytoskeleton fibers to extracellular collagen & other protein fibers |
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Term
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Definition
| catalyze chemical reactions that take place either on the cell's external surface or just inside the cell |
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Term
| What type of proteins are part of the body's chemical signaling system? |
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Definition
| membrane receptor proteins |
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Term
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Definition
| move molecules across membranes |
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Term
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Definition
| create water-filled passageways that directly link the intracellular & extracellular compartments |
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Term
| carrier proteins (AKA transporters) |
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Definition
| bind to substrates that they carry but never form a direct connection between the ICF and ECF |
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Term
| What type of channels are made from the protein "aquaporin"? |
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Definition
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Term
| How many types of ion channels have been identified? |
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Definition
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Term
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Definition
| spend most of their time with their gate open, allowing ions to move back & forth across the membrane without regulation |
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Term
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Definition
| spend most of their time in a closed state, which allows them to regulate the movement of ions through them |
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Term
| For chemically gated channels, the gating is controlled by _____ or _____ that bind to the channel protein |
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Definition
| intracellular messenger molecules or extracellular ligands |
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Term
| Voltage-gated channels open & close when _____ |
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Definition
| the electrical state of the cell changes |
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Term
| Mechanically gated channels respond to _____ |
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Definition
| physical forces, such as increase temperature or pressure that puts tension on the membrane & pops the channel open |
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Term
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Definition
| carrier proteins that move only one kind of molecule |
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Term
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Definition
| a carrier that moves more than one kind of molecule at one time |
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Term
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Definition
| carrier proteins that transport molecules in the same direction, whether into or out of the cell |
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Term
| antiport carriers (AKA exchangers) |
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Definition
| carrier proteins that carry molecules in opposite directions |
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Term
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Definition
| a family of carrier proteins that move glucose & related hexose sugars across membranes |
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Term
| Where does the energy come from for primary (direct) active transport? |
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Definition
| directly from the high-energy phosphate bond of ATP |
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Term
| Where does the energy come from for secondary (indirect) active transport? |
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Definition
| potential energy stored in the concentration gradient of one molecule to push other molecules against their concentration gradient |
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Term
| Why are many primary active transporters known as ATPases? |
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Definition
| primary active transport uses ATP as its energy source |
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Term
| 4 steps for Na+-glucose secondary active transport (SGLT) |
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Definition
1. sodium binds first & causes a conformational change in the protein that creates a high-affinity binding site for glucose
2. glucose binds to SGLT
3. the protein changes conformation again & opens its channel to the ICF side
4. the loss of Na+ from the protein changes the binding site for glucose back to a low-affinity site, so glucose is released & follows Na+ into the cytoplasm |
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Term
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Definition
| the maximum number of molecules that can be transported by the carrier proteins if they are all functioning at the same time |
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Term
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Definition
| the actin-mediated process by which a cell engulfs a bacterium or other particle into a large membrane-bound vesicle |
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Term
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Definition
| the membrane-bound vesicle into which a cell engulfs a particle in phagocytosis |
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Term
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Definition
| the process by which large molecules or particles move into cells |
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Term
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Definition
| when endocytosis is nonselective, allowing ECF to enter the cell |
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Term
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Definition
| the region of the cell membrane where receptor-mediated endocytosis takes place; indentations where the cytoplasmic side of the membrane has high concentrations of protein |
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Term
| 9 steps of receptor-mediated endocytosis |
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Definition
1. extracellular ligands that will be brought into the cell bind to their membrane receptors
2. the receptor-ligand complex migrates along the cell surface until it encounters a coated pit
3. the membrane draws inward (invaginates)
4. the clathrin molecules are released & recycle back into the membrane
5. in the vesicle, the receptor & ligand separate, leaving the ligand inside an endosome
6. the endosome moves to a lysosome if the ligand is to be destroyed, or to the Golgi complex if the ligand is to be processed
7. the vesicle with the receptors moves to the cell membrane
8. the vesicle fuses with the cell membrane
9. the vesicle membrane is incorporated back into the cell membrane by exocytosis |
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Term
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Definition
| when the ligand's membrane-bound receptors are reused |
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Term
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Definition
| small flask-shaped indentations that some endocytosis uses to concentrate & bring receptor-bound molecules into the cell |
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Term
| What is the opposite of endocytosis? |
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Definition
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Term
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Definition
| how cells export large lipophobic molecules & get rid of wastes left in lysosomes from intracellular digestion |
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Term
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Definition
| transport of material from the lumen of an organ to the ECF |
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Term
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Definition
| movement across an epithelium |
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Term
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Definition
| epithelial transport that takes place through the junctions between adjacent cells |
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Term
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Definition
| epithelial transport that takes place through the epithelial cells themselves |
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Term
| 3 steps for the transepithelial absorption of glucose |
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Definition
1. Na+-glucose symporter brings glucose into cell against its gradient using energy stored in the Na+ concentration gradient
2. GLUT transporter transfers glucose to ECF by facilitated diffusion
3. Na+-K+-ATPase pumps Na+ out of the cell, keeping ICF Na+ concentrations low |
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Term
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Definition
| a combination of endocytosis, vesicular transport across the cell, & exocytosis; used for molecules that are too large to cross epithelia on membrane transporters |
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Term
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Definition
| how the vesicle that encompasses the molecule brought into an epithelial cell in transcytosis is moved across the cell after attaching to microtubules in the cell's cytoskeleton |
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Term
| law of conservation of electrical charge |
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Definition
| the net amount of electrical charge produced in any process is zero |
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Term
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Definition
| the material through which separated positive & negative charges can move freely toward each other |
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Term
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Definition
| the material that separates charges & does not allow the charges to move through it |
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Term
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Definition
| a difference in the net charge between two regions; ex) can be caused by the movement of K+ out of the cell down its concentration gradient |
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Term
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Definition
| the combination of electrical & concentration gradients |
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Term
| equilibrium potential (AKA Eion) |
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Definition
| the membrane potential that exactly opposes the concentration gradient for any given concentration gradient of a single ion |
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Term
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Definition
| Eion = 61/(electrical charge on ion) x log([ion]out/[ion]in) |
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Term
| resting membrane potential difference (AKA membrane potential) |
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Definition
| the electrical disequilibrium; electrical gradient between the ECF & ICF |
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Term
| 2 factors that influence a cell's membrane potential |
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Definition
1. the concentration gradients of different ions across the membrane
2. the permeability of the membrane to those ions |
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Term
| 2 channels of a beta cell that help control insulin release |
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Definition
1. voltage-gated Ca2+ channel
2. ATP-gated K+ channel (AKA KATP channel) |
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Term
| 7 steps for a beta cell secreting insulin |
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Definition
1. high glucose levels in blood
2. metabolism increases
3. ATP increases
4. KATP channels close
5. cell depolarizes & calcium channels open
6. Ca2+ entry acts as an intracellular signal
7. Ca2+ signal triggers exocytosis & insulin is secreted |
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