BRS Physiology
1. Cell Physiology
Terms : Hide Images
| 423444080 | Cell membranes are composed primarily of what? | phospholipids and proteins | |
| 423444081 | Describe the phospholipids in the phospholipid bilayer | phospholipids have a glycerol backbone which is hydrophilic and two fatty acid tails which are hydrophobic. The hydrophobic tails face eachother and form a bilayer | |
| 423444082 | can lipid soluble substances cross cell membranes? | O2, CO2, steroids cross cell membranes because they dissolve in the hydrophobic lipid layer | |
| 423444083 | can water soluble substances cross cell membranes? | Na+, Cl-, H2O cannot dissolve in the lipid of the membrane, but may cross through water filled channels or be transported by carriers | |
| 423444084 | What are the types of proteins in cell membranes? | integral proteins peripheral proteins | |
| 423444085 | how are integral proteins anchored to the cell membrane? | hydrophobic interactions | |
| 423444086 | can integral proteins span the cell membrane? | yes | |
| 423444087 | what are examples of integral proteins? | ion channels transport proteins receptors G proteins | |
| 423444088 | are peripheral proteins embedded in the cell membrane? | no | |
| 423444089 | are peripheral proteins covalently bound to membrane components? | no | |
| 423444090 | how are peripheral proteins attached to the cell membrane? | loosely by electrostatic interactions | |
| 423444091 | What are the types of intercellular connections? | tight junctions Gap junctions | |
| 423444092 | what is another term for tight junctions? | zona occludens | |
| 423444093 | tight junctions are often the attachments between which kind of cells? | epithelial cells | |
| 423444094 | can tight junctions be an intercellular pathway for solutes? | yes, depending on: size, charge, characteristics of the tight junction | |
| 423444095 | what are the two types of zona occludens? | tight leaky | |
| 423444096 | what are tight zona occludens and where are they seen? | impermeable renal distal tubule | |
| 423444097 | what are leaky zona occludens and where are they seen? | permeable renal proximal tubule and gallbladder | |
| 423444098 | What are gap junctions? | the attachments between cells that permit intercellular communication | |
| 423444099 | what is an example of gap junctions? | those that permit current flow and electrical coupling between myocardial cells | |
| 423454503 | what are the characteristics of simple diffusion? | only form of transport that is not carrier mediated occurs down electrochemical gradient does not require metabolic energy | |
| 423454504 | What is the equation for measuring simple diffusion? | J = -PA (C1-C2) J= flux [mmol/sec] P= permeability [cm/sec] A= area [cm^2] C1= concentration1 [mmol/L] C2= concentration2 [mmol/L] | |
| 423454505 | what is the meaaning of the minus sign preceding the diffusion equation? | the direction of flux is from high to low concentration. | |
| 423454506 | when can the minus sign preceding the diffusion equation be ignored? | if the higher concentration is called C1 and the lower concetration called C2 | |
| 423454507 | Simple diffusion across electrochemical gradient: uphill or downhill? | downhill | |
| 423454508 | Facilitated diffusion across electrochemical gradient: uphill or downhill? | downhill | |
| 423454509 | Primary active transport across electrochemical gradient: uphill or downhill? | uphill | |
| 423454510 | cotransport across an electrochemical gradient: uphill or downhill? | uphill | |
| 423454511 | countertransport across an electrochemical gradient: uphill or downhill? | uphill | |
| 423454512 | is simple diffusion carrier mediated? | no | |
| 423454513 | is facilitated diffusion carrier mediated? | yes | |
| 423454514 | is primary active transport carrier mediated? | yes | |
| 423454515 | is cotransport carrier mediated? | yes | |
| 423454516 | is countertransport carrier mediated? | yes | |
| 423454517 | does simple diffusion require metabolic energy? | no | |
| 423454518 | does facilitated diffusion require metabolic energy? | no | |
| 423454519 | does primary active transport require metabolic energy? | yes | |
| 423454520 | does cotransport require metabolic energy? | indirectly | |
| 423454521 | does countertransport require metabolic energy? | indirectly | |
| 423454522 | does simple diffusion exploit a sodium gradient? | no | |
| 423454523 | does facilitated diffusion exploit a sodium gradient? | no | |
| 423454524 | does cotransport exploit a sodium gradient? | yes, same direction | |
| 423454525 | does countertransport exploit a sodium gradient? | yes, opposite direction | |
| 423454526 | what does inhibition of the Na/K pump do to primary active transport | inhibits if the transport in question is the Na/K pump | |
| 423454527 | what does inhibition of the Na/K pump do to cotransport? | inhibits | |
| 423454528 | what does inhibition of the Na/K pump do to countertransport? | inhibits | |
| 423454529 | permeability describes what? | the ease with which a solute diffuses through a membrane | |
| 423454530 | what does permeability depend on? | the characteristics of the solute and the membrane | |
| 423454531 | what are the factors that increase permeability? | increased oil/water partition coefficient decreased radius of the solute decreased membrane thickness | |
| 423454532 | what has the highest permeabilities in lipid membranes? | small hydrophobic solutes | |
| 423454533 | what does the flux of an ion across a membrane depend on? | concentration difference potential difference | |
| 423454534 | what are the types of carrier mediated transport? | facilitated diffusion primary active transport secondary active transport | |
| 423454535 | What are the characteristics of carrier mediated transport? | stereospecificity saturation competition | |
| 423454536 | what is an example of stereospecificity? | D-glucose is not transported by facilitated diffusion | |
| 423454537 | what is an example of competition in carrier mediated transport? | galactose is a competitive inhibitor of glucose transport in the small intestine | |
| 423459241 | What are the characteristics of facilitated diffusion? | occurs down electrochemical gradient does not require metabolic energy and is passive more rapid than simple diffusion is carrier mediated and therefore exhibits stereospecificity, saturation, and competition | |
| 423459242 | which is more rapid, simple diffusion or facilitated diffusion? | facilitated diffusion | |
| 423459243 | what is an example of facilitated diffusion? | glucose transport in muscle and adipose cells | |
| 423459244 | why is glucose uptake by adipose and muscle impaired in diabetes mellitus? | carriers for facilitated diffusion of glucose require insulin | |
| 423459245 | what are the characteristics of primary active transport? | uphill requires ATP/is active is carrier mediated so exhibits saturation, stereospecificity and competition | |
| 423459246 | what are examples of primary active transport? | Na-K pump Ca2+ pump proton pump | |
| 423459247 | what is the usual stoichiometry of the Na-K pump? | 3Na/2K | |
| 423459248 | what are the specific inhibitors of the Na-K pump? | cardiac glycosides: ouabain digitalis | |
| 423459249 | where is the Ca2+ pump? | sarcoplasmic reticulum | |
| 423459250 | what is the sarcoplasmic reticulum and endoplasmic reticulum Ca++pump called? | SERCA | |
| 423459251 | where is the proton pump? | gastric parietal cells | |
| 423459252 | what inhibits the proton pump? | omeprazole | |
| 423462072 | What are the characteristics of secondary active transport? | transport of >=2 solutes is coupled one of the solutes moves downhill and provides the energy for the uphill transport of the other solute energy is provided indirectly by the Na+ gradient | |
| 423462073 | what are examples of symport? | Na+-glucose cotransport in small intestine Na+-K+-2Cl- cotransport in thick ascending limb | |
| 423462074 | what are examples of countertransport? | Na-Ca exchange Na-H exchange | |
| 423462075 | What does inhibition of the Na-K pump on the basolateral side of cells of the renal proximal tubule do to Na-Glucose transport on the luminal side? | decreases the transmembrane Na gradient and consequently inhibits Na-Glucose transport | |
| 423462076 | what does poisoning the Na-K pump do to Na-Ca exchange? | inhibits it |
