Instructions: pIease Read AII CarefuIIy

.         This is a timed practice set.  You will have 48 hours to complete the Practice set; however,

we expect that you will be able to complete these problems in 1一3 hours. To receive your fuII 48-h window, you must downIoad your exam at the start your Discussion section.

.         This Practice set is designed to mimic a typical midterm exam. All of the questions are taken from previous years， midterm exams or graded problem sets.  Problems earn points based on effort. Blank or irrelevant answers will not earn points.

.         Carefully read through each question before you start working on the PRACTICE sET.

.         This is an open note/book problem set. You may consult online resources, lecture notes, required content and optional reading.  You may discuss the problems in your study groups and in discussion sections; however, you must submit your own independent answers.

.         Your    answers   must    be      written    within      the      box      provided.    AND   your

uploaded      Ps  must match the template*  一 questions and    answers  must  be    on   the   same page,   in   the    same  place.  You can  type an answer  using    12-point      font      into      the

PDF   fields.   or      you   can    print  the  problem  set  and  write  in  your  answers  using  clear handwriting  that  is  no  smaller  than  the  problem  set  font.  Illegible answers and information written outside the box (or not on the blank) will not be graded.

*practice sets not matching the template might lose points as a result

.         You must convert your practice set to a pdf and submit via gradescope with  "Your Name一Ps1" as the filename.

.         To be eIigibIe for fuII Points, the comPIeted practice set must be submitted no Iater    than 48-hours after you access the probIem set ( e.g., if you open the assignment on Tues.  at 10am, your practice set is due Thurs. at 10am). Assignments submitted after that time will be eligible for half credit.

.         Honorstatement: I swearon my honor that:

-l have read all of the instructions.

-l will turn in my own original work.

-l understand that this assignment maybe validated for originality via Turnitin according to Uc policies:

h:ttps ://dls.berkeley.edu/services/academic Ⅷ integrity/turnitin Ⅷ instructors Ⅷ getting Ⅷ started/ turnitin Ⅷ policies

.   l    will    not    share     this    problem     set    with     anyone    outside     my    discussion section.

1.   physiologists   draw    conclusions   about    how   cells   work   based   on   scientific measurements.   Even with  highly  sensitive  equipment， these measurements are not 100% precise.   To account for their level of uncertainty， scientists pay attention to the number of significant figures they use to report experimental results.

The Table below lists the basic rules for determining the number of significant figures in a value.  The middle column contains values from measurements, and the right column lists the number of significant figures in each value.

lndicate (by circling, boxing, etc) the significant figures in each example value. (0.6 pt)

use these ruIes to determine the number of significant figures for the resuIts of caIcuIations beIow, and throughout the cIass.

2. You isoIate a heat-sensitive somatosensory neuron from an individuaI with pain

hypersensitivity. (3.5 pts)

use these parameters to answer the following questions. show all work for full credit.

Intracellular: 120 mM K+ ; 5.0 mM Na+ ; 50. mM Cl- ; 0.0001 mM Ca2+

Extracellular: 5.0 mM K+ ; 150. mM Na+ ; 50. mM Cl- ; 2.0 mM Ca2+

permeability values at rest: pK+  = 1.0, pNa+  = 10., pCa2+  = 0.0 and pCl-  = 50.

A. CaIcuIate the resting potentiaI of this neuron.   set up your equation(s) and show your work. Express your answer to  two significant figures. (1 pt)

B. CaIcuIate           the     foIIowing      EquiIibrium      potentiaIs.     Ek+,      ENa+,      and     ECI-          and

set          up  your equation(s) and show your work.  Express your answer to two significant figures. (2 pts)

Ek+

ENa+

ECI

C.  If an ion channeI opens when this ceII is at rest, state the net  fIux (infIux, effIux, or no net

fIux) for each of the foIIowing ions. use the above vaIues to answer this question (0.4 pt)

k+                ;  Na+             ; CI-           ;     ca2+