Use the following to answer questions 14-16. You discovered a new organism and a
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Use the following to answer questions 14-16. You discovered a new organism and are studying its chemical and e properties. You started the project by measuring the ionic concentrations (mEq/L) inside and outside the or membrane potentials. The data collected are shown below: lon ganism and its ECF (mEq/L K* Na* Ca*2 You recorded a resting membrane potential (RMP) at-60mV. Based on your understanding of mammalian neurophysiology and the above preliminary data, answer the following 2 questions ICF (mEq/) 140 10 0.004 14 120 1.2 14. When the unicellular organism was electrically stimulated in an isotonic solution containing 40 mEq/t Ca* and 10 mEa/L Na', no AP was observed. Which of the following would be TRUE? A. There may be no voltage-gated channels for Ca 2 on the membrane B. ECF [Ca would decrease the chemical gradient C. Ca+2 influx may make the RMP more negative D. There are Ca+2 leak channels on the membrane but they are already saturated 15. When the unicellular organism was electrically stimulated in an isotonic solution containing 240 mEa/L Na*, an AP was observed with a shape similar to that of mammalian neurons. Which of the following would be TRUE? A. Na efflux would happen more often B. There are K+ voltage-gated channels C. There are Na+ voltage-gated channels D. T ECF IK'] would decrease the chemical gradient its gradient, the carrier protein involved C. is an exchanger and indirectly uses ATP D. is a cotransporter and directly uses ATP 16. If Ca+2 is moving along its gradient and Nat is moving against A. is an antiporter and a primary active transporter B. is a sympor rter and a secondary active transporterExplanation / Answer
14.
A.There may be no voltage gated channels for Ca+ on the membrane.
For the process of action potential there must be voltage gated Ca+ channeks for Ca+ influx .Ca+ influx facilitate action potential.
Remaining options are not true. because
Increased ECF (Ca+) would causes rush of calcium ion into the cell than action potential may activated.
Increased calcium influx initiates action potential.
Ca+ leak channels facilitate calcium influx. So ultimately it causes action potential.
15.
C.There are Na+ voltage gated channels.
Presence of Na+ voltage gated channels causes Na+ influx. That initiates action potential. So it is true.
Where as the remaining options
During the action potential Na+ eflux doesn't occur.if it is happen it leads to resting membrane potential.
If there is voltage gated K+ channels it leads to K+ eflux makes the cell more negative inside which is resting membrane potential.
Increased ECF (K+) would causes negative inside the cell, makes the resting membrane potential.
16.
C.is the exchanger and indirectly uses ATP.
Sodium and calcium exchanger is denoted as Na+/Ca+ exchanger or exchanger protein is the antiporter membrane that moveouts the calcium out of cell. It utilizes the energy stored in electrochemical gradient of the sodium ion ( secondary active transport).
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