OldTest (exam1)

OldTest (exam1) - Examination I VPHY 3100 Elements of...

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Examination I VPHY 3100 Elements of Physiology September 15th, 2008 1:25 - 2:15 p.m. Multiple Choice (2.5 points each) FOR EACH QUESTION, CHOOSE THE SINGLE BEST ANSWER. 1. What is the primary impediment to the simple diffusion of ions and most molecules across the cell membrane? A. The charged nature of the head groups on phospholipid molecules within the bilayer. B. The hydrophilic nature of the head groups on phospholipid molecules within the bilayer. C. The central core of the bilayer, composed of hydrophobic hydrocarbon chains. D. The central core of the bilayer, composed of hydrophilic hydrocarbon chains. E. The inability of membrane transport proteins to function properly. 2. Molecular oxygen (O 2 ) crosses cell membranes by: A. osmosis. B. primary active transport. C. secondary active transport. D. simple diffusion. E. facilitated diffusion. 3. A _____________________ solution exerts more osmotic pressure than a 200 millimolar NaCl solution. A. 200 millimolar CaCl 2 B. 200 millimolar glucose C. 100 millimolar NaCl D. 100 millimolar MgCl 2 E. 300 millimolar glucose 4. Which statement is true ? A. All ion channels are passive transport proteins. B. All pumps engage in secondary active transport. C. All carriers mediate facilitated diffusion. D. All uniporters engage in secondary active transport. E. None of the above are correct. 5. Which statement is true for both symporters and antiporters? A. Solutes move in the same direction across the membrane. B. Solutes move in opposite directions across the membrane. C. At least one solute moves against its chemical (or electrochemical) gradient across the membrane. D. These carriers hydrolyze ATP in order to move solutes across the membrane. E. These carriers are passive transporters. 6. In order for the sodium/glucose cotransporter to function properly, it relies on the _________________ + /K + -ATPase. A. potassium gradient B. sodium gradient C. glucose gradient 1
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D. chloride gradient E. calcium gradient 7. The sodium pump contributes slightly to the resting membrane potential because: A. it is an electroneutral pump. B. it moves one net positive charge out for each ATP hydrolyzed. C. it moves one net positive charge in for each ATP hydrolyzed. D. it keeps internal potassium concentrations high. E. it keeps internal potassium concentrations low. 8. The typical charge gradient that exists across our cell membranes at rest: A. results in a membrane potential around 0 mV. B. results in a membrane potential around -30 mV. C. results in a slightly depolarized membrane potential. D. is characterized by excess positive charges in the cytoplasm. E. is characterized by excess negative charges in the cytoplasm. 9. The resting membrane potential across our cells is very close to E K primarily due to: A. “leaky” K channels which are open at rest. B. “leaky” Na channels which are open at rest.
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OldTest (exam1) - Examination I VPHY 3100 Elements of...

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