USMLE Step 1: Physiology 4. Facilitated diffusion can be distinguished from simple diffusion by which of the following A. facilitated diffusion is saturable, simple diffusion is not B. facilitated diffusion requires ATP, sumple diffusion does not C. facilitated diffusion is not chemically specific, simple diffusion is D. facilitated diffusion is dependent on concentration gradient, simple diffusion is not Questions 5 and 6 Red blood cells are placed in a beaker containing one of the following solutions. Ignoring ransient(initial)changes, predict the effect of the solution on red blood cell volume A. increase in cell volume B. decrease in cell volum C. no change in cell volume 5. 200 mOsm sodium chloride 6. 400 mOsm glycerol Questions 7 and 8 0 Time(seconds) The diagram above illustrates possible changes in red blood cell volume resulting from a change in extracellular luid composition for a cell equilibrated in 150 mM/L NaCl solution at time 0 7. Which curve best illustrates the volume caused by immersion of the cell into an aqueous solution of 300 mOsm CaCI? 8. Which curve best illustrates the volume change caused by immersion of the cell into an aqueous solution of 200 mOsm/L NaCl and 200 mOsm/L glycerol? 22 medical
USMLEStep 1: Physiology 22 KAPLA~. meulca I 4. Facilitated diffusion can be distinguished from simple diffusion by which of the following statements? A. B. e. D. facilitated diffusion is saturable, simple diffusion is not facilitated diffusion requires ATP,simple diffusion does not facilitated diffusion is not chemically specific,simple diffusion is facilitated diffusion is dependent on concentration gradient, simple diffusion is not Questions 5 and 6 Red blood cellsare placed in a beaker containing one of the following solutions. Ignoring transient (initial) changes, predict the effect of the solution on red blood cellvolume. A. B. e. increase in cell volume decrease in cell volume no change in cell volume 5. 200 mOsm sodium chloride 6. 400 mOsm glycerol Questions 7 and 8 A <D E :::I (5 > ;m :E E B c D 0 Time (seconds) The diagram above illustrates possible changes in red blood cell volume resulting from a change in extracellular fluid composition for a cell equilibrated in 150 mM/L NaCl solution at time O. 7. Which curve best illustrates the volume caused by immersion of the cellinto an aqueous solution of 300 mOsm CaC12? 8. Which curve best illustrates the volume change caused by immersion of the cell into an aqueous solution of 200 mOsm/L NaCI and 200 mOsm/L glycerol?
stions 9 and 10 In the above Dannett-Yarrow diagrams, the dashed boxes represent original conditions of intra cellular space ()and extracellular space(E). The x axis is volume and the y axis represent osmolarity. 9. Which of the diagrams best illustrates the changes in fluid compartments resulting from 10. Which of the diagrams best illustrates the changes in fluid compartments resulting from nfusion of 300 mOsm/L NaCl solution? 11. Select the Dannett-Yarrow diagram(below)which best illustrates the before(dashed) and after(solid) status of a person who received 1 L of a hypertonic saline solution intra IE B medical 23
ReviewQuestions Questions 9 and 10 ..--------- A. !L i]E l:~ D.D ~ B.0 lf::1] c. r~ j i~l J E.I ItcJJ In the aboveDannett-Yarrowdiagrams,the dashedboxesrepresentoriginalconditionsof intracellular space (I) and extracellular space (E). The x axis is volume and the y axis represents osmolarity. 9. Which of the diagrams best illustrates the changes in fluid compartments resulting from loss of pure water from the body? Which of the diagrams best illustrates the changes in fluid compartments resulting from infusion of 300 mOsm/L NaCl solution? Selectthe Dannett-Yarrow diagram (below) which best illustrates the before(dashed) and after (solid) status of a person who received 1 L of a hyp<:rtonic saline solution intravenously. 10. 11. J\.[~j~~ ijt~ ~I B. r=Ji 'l-E t=J D.0 ;0 C.!i-~ I E : .-- I I E.: I E' ! ~ ~ I I KAPLA~. meulCa I 23
USMLE Step 1: Physiology 12. In the diagram below, two water-filled chambers are separated by a semipermeable mem brane. Choose the diagram which best illustrates the volumes of the two chambers at equilibrium after 100 mOsm/L of a permeating solute is added to chamber X X 13. The most rapid form of transport over a distance greater than I cm is simple diffusion B. facilitated diffusion C. primary active transport D. secondary active transport E. bulk flow(now duc to pressure differences 14. Which of the following diagrams best illustrates the fluid shifts resulting from infusion of I Lof distilled water into the bloodstream( dashed lines represent original conditions and solid lines the final steady-state situation)? 24 medical
USMLEStep 1: Physiology 24 KAPLANiI' . me leaI 12. In the diagram below,two water-filled chambers are separated by a semipermeable membrane. Choose the diagram which best illustrates the volumes of the two chambers at equilibrium after 100 mOsm/L of a permeating solute is added to chamber X. x y 0 A 8 c D E x y x y x y x y x y 0 0 0 0 0 13. The most rapid form of transport over a distance greater than 1 cm is: A. B. e. D. E. simple diffusion facilitated diffusion primary activetransport secondary active transport bulk flow (flow due to pressure differences) 14. Which of the following diagrams best illustrates the fluid shifts resulting from infusion of 1 L of distilled water into the bloodstream (dashed linesrepresent originalconditionsand solid linesthe final steady-statesituation)? A. :..------ - IJE- - -: B. : ~r;-- ; I I I D.I lIE D c. J--,O: E.I f - - - - -, rE- - -: I
Review questions 15. Which of the following characteristics is not associated with facilitated diffusion B. competitive inhibition by structurally similar substrates C. saturation kinetics D. direct dependence on ATP concentration 16. Check each of the following statements concerning intracellular fluid that is true L. it contains more than 50% of the body water 2. it has a higher osmotic pressure than extracellular Quid 3. it has a higher concentration of organic anions than extracellular fluid Which one of the following best summarizes your conclusions? A. statement 1 is true B. statement 2 is true C. statements I and 2 are true D. statements I and 3 are true E, statements 1, 2, and 3 are true 17. Check each of the following statements concerning the diffusion of water that is true: 1. the net flux of water is from an area of low solute concentration to an area of high solute concentration 2. requires a semipermeable membrane 3. is an energy-requiring process Which one of the following best summarizes your conclusions? A. statement I is true B. statement 2 is true C. statement 3 is true D. statements 2 and 3 are true E. statements 1,2 and 3 are true 18. One liter of isotonic saline was injected intravenously into a 70-kg woman. Assume the injection had no significant effect on capillary hydrostatic pressure. After 15-30 minutes the(check each correct answer) 1. extracellular water would increase by more than 900 ml 2. interstitial water would increase by more than 900 ml 3. intracellular water would increase by more than 900 ml 4. plasma water would increase by more than 900 ml 5. total body water would increase by more than 900 ml 19. If I month later, I liter of plasma was given intravenously to the woman in question 18, and once again the capillary hydrostatic pressure stayed constant, what would be the effect on fluid volume 15-30 minutes after the injection(choose one or more correct answers from possibilities I through 5 in question 18)? medical 2
ReviewQuestions 15. 16. 17. 18. 19. Which of the following characteristics is not associated with facilitated diffusion: A. B. e. D. stereospecificity for substrate competitive inhibition by structurally similar substrates saturation kinetics direct dependence on ATP concentration Check each of the following statements concerning intracellular fluid that is true: 1. it contains more than 50% of the body water 2. it has a higher osmotic pressure than extracellular fluid 3. it has a higher concentration of organic anions than extracellular fluid Which one of the following best summarizes your conclusions? A. statement 1 is true B. statement 2 is true e. statements 1 and 2 are true D. statements 1 and 3 are true E. statements 1, 2, and 3 are true Check each of the following statements concerning the diffusion of water that is true: 1. the net flux of water is from an area of low solute concentration to an area of high solute concentration 2. 3. requires a semipermeable membrane is an energy-requiring process Which one of the following best summarizes your conclusions? A. B. e. D. E. statement 1 is true statement 2 is true statement 3 is true statements 2 and 3 are true statements 1,2, and 3 are true One liter of isotonic saline was injected intravenously into a 70-kg woman. Assume the injection had no significant effect on capillary hydrostatic pressure. After 15-30 minutes the (check each correct answer) 1. 2. 3. 4. 5. extracellular water would increase by more than 900 ml interstitial water would increase by more than 900 ml intracellular water would increase by more than 900 ml plasma water would increase by more than 900 ml total body water would increase by more than 900 ml If 1 month later, 1 liter of plasma was given intravenously to the woman in question 18, and once again the capillary hydrostatic pressure stayed constant, what would be the effect on fluid volume 15-30 minutes after the injection (choose one or more correct answers from possibilities 1 through 5 in question 18)? metlical 25
USMLE Step 1: Physiology 20. If two months later, I liter of an isosmolar solution of urea was injected intravenously into the woman in question 18, and once again the capillary hydrostatic pressure stayed con tant, what would be the effect on Ouid volume 15-30 minutes after the injection(choose one or more correct answers from possibilities I through 5 in question 18)? 21. The following diagram shows the rate of entry of various molecules into a Intrac Choose the correct statement A. If curves F and G represent molecules that enter only by diffusion tbrough pores. then curve F represents the diffusion of a larger molecule than curve G B. If curves G and H represent molecules that enter only through the lipid portion of the cell membrane, then curve H represents a less lipid-soluble molecule than curve G C. If curve F represents an ion being moved by facilitated diffusion, then curve g rep resents the movement of the same ion after ATPase inhibition by ouabain D. If curve H represents a molecule being moved by facilitated diffusion, then curve G represents the movement of the same molecule after the addition of a molecule of similar chemical structure 22. A 60-kg patient has a hematocrit reading of 40 and a plasma volume of 3 liters. What is his total blood volume? A. 4.0 liters B. 5.0 liters C. 6.0 liters D. 7.0 liters e. greater than 7.5 liters 26 medical
USMLEStep1: Physiology 26 KAPLA~. meulC8 I 20. If two months later, 1liter of an isosmolar solution of urea was injected intravenously into the woman in question 18, and once again the capillary hydrostatic pressure stayed constant, what would be the effecton fluid volume 15-30 minutes after the injection (choose one or more correct answers from possibilities 1 through 5 in question 18)? 21. The following diagram shows the rate of entry of various molecules into a cell: 150 Intracellular concentration (% of extracell. cone.) F ------ -- -- /' /' H -- /' , / /' ,(...::""""" / .p'" G / /" // // / / //' /' 100 50 0 0 Time (seconds) Choose the correct statement. A. If curves F and G represent molecules that enter only by diffusion through pores, then curve F represents the diffusion of a larger molecule than curve G. If curves G and H represent moleculesthat enter only through the lipid portion of the cellmembrane, then curve H represents a less lipid-soluble molecule than curve G. If curve F represents an ion being moved by facilitated diffusion, then curve G represents the movement of the same ion after ATPaseinhibition by ouabain. If curve H represents a molecule being moved by facilitated diffusion, then curve G represents the movement of the same molecule after the addition of a molecule of similar chemical structure. B. e. D. 22. A 60-kg patient has a hematocrit reading of 40 and a plasma volume of 3 liters. What is his total blood volume? A. B. e. D. E. 4.0 liters 5.0 liters 6.0 liters 7.0 liters greater than 7.5 liters