Lecture 1 8/23/23 Flashcards
What are the five main physiologic categories of protein function?
-catalysis of reactions
-reaction coupling
-membrane transport
-cell structure/support
-molecular signaling
What are the effects of proteins as catalyzers?
-speeds up reaction time
-does not change net products or energy change
How do proteins function in reaction coupling?
facilitating the pairing of rxns so the energy from one can supply the other
Which rxn within the body is a big example fo rxn coupling?
ATP hydrolysis (addition of water to produce ADP and Pi)
How are proteins involved in signaling?
-membrane proteins that accept signals
-aid in signal transduction
What is an allosteric protein?
a protein that changes shape when another molecule binds to it
Why are allosteric proteins important?
the change that occurs when the molecule binds alters the activity and/or properties of the protein
How does ligand binding affect allosteric proteins?
the binding of a ligand can open or close binding sites, providing/reducing signaling abilities
How does phosphorylation play a role in allosteric changes?
phosphorylation can lead to changes in protein shape, allowing for the attachment/disattachment of various molecules to channel proteins
How does voltage play a role in allosteric changes?
voltage can lead to the opening or closing of channels, preventing or encouraging the movement of molecules
What molecules are able to pass through the pure lipid bi-layer?
-small polar molecules, like water and urea
-non-polar, fat-soluble molecules
What molecules are not able to pass through the pure lipid bi-layer?
-ions
-large polar molecules
How do chemical forces impact molecular movement?
molecules want to move from areas of high concentration to areas of low concentration
How do electrical forces impact molecular movement?
molecules want to move from areas of similar charge to areas of opposite charge
How do chemical and electrical forces both impact molecular movement?
the combined force of chemical and electrical forces will determine the way in which molecules move
What is diffusion/passive transport?
spontaneous movement of particles from areas of high electrochemical concentration to areas of low concentration
What is osmosis?
the movement of water from areas of high water conc. to low conc. (water follows solute)
What is water pressure?
-water pressure required to bring system to equilibrium
-balance of pressure and concentration
What is oncotic pressure?
osmotic pressure resulting from dissolved proteins
How does protein impact water movement?
-proteins will pull water into blood vessels
-low albumin (protein) in the vessels means water will likely leave the vessels
How does hydrostatic pressure impact a blood vessel?
-closest to the heart, higher hydrostatic pressure will push water out (filtration)
-furthest from the heart, lower hydrostatic pressure + greater protein conc. will draw water in (reabsorption)
How can both the heart or albumin levels cause a fluid filled abdominal cavity?
-heart: inc. water pressure due to heart failure
-albumin: low levels lead to low oncotic pressure and water leaving vessels
What is active transport?
the utilization of energy/work to move molecules against their electrochemical gradient
What is the main example of active transport?
sodium-potassium pump
What is secondary active transport?
-couples the movement of one molecule with its gradient to the movement of another molecule against its gradient
-molecule moving with its gradient can bring in other molecules
What is facilitated diffusion?
-use of protein carriers to move ions and larger molecules from high to low conc.
What are the potential methods of facilitated diffusion?
-ungated channels
-carriers
-ligand-gated channels
-voltage-gated channels
What is the function of aquaporins?
to move water at a much faster rate than osmosis
What is transcellular/epithelial transport?
movement of particles across a membrane through the engulfment of said particles by the membrane
