MCB 136, Fall 2023 Practice Set 1 (PS1)
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MCB136,FaII 2023
Practice set 1 (ps1)
5 points
Due 48 hours after you open the assignment
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+
3. Na+ k+ATpase (1 pts)
You use CRISpR gene editing to mutate the Na+/k+ATpase gene. For each ATp hydroIyzed, the
mutant pump transports 3 Na+ into the ceII, and 2 k+ out of the ceII. Compare AND contrast the
reIative Na+ and k+ ion concentrations inside and outside ceIIs expressing wiIdtype versus
mutant Na+/k+ATpases.
For fuII credit, describe at Ieast
concentration.
2023-09-13