11/27/21, 2:14 PM Midterm Exam 1: BIO SCI D103 LEC A: CELL BIOLOGY (05530) Midterm Exam 1 Due Oct 15 at 3pm Points 20 Questions 20 Available Oct 15 at 12pm - Oct 15 at 3pm about 3 hours Time Limit 60 Minutes This quiz was locked Oct 15 at 3pm. Attempt History LATEST Attempt Time Score Attempt 1 60 minutes 9 out of 20 Score for this quiz: 9 out of 20 Submitted Oct 15 at 1:44pm This attempt took 60 minutes. Question 1 0 / 1 pts Fluorescent probes have excitation and emission wavelengths. What is the most likely reason overlap between these wavelengths is an important factor to consider? ou Answered Minimizing overlap between excitation wavelengths of two fluorescent proteins will enhance the resolution of each protein Overlap between excitation wavelengths of two fluorescent proteins will allow each to be resolved using the same laser Minimizing overlap between excitation and emission wavelengths of two fluorescent proteins will prevent the resolution of each protein https://canvas.eee.uci.edu/courses/40270/quizzes/187689 1/14 11/27/21, 2:14 PM Midterm Exam 1: BIO SCI D103 LEC A: CELL BIOLOGY (05530) orrect Answer Overlap between excitation and emission wavelengths of two fluorescent proteins will prevent the resolution of each protein Overlap between emission wavelengths of two fluorescent proteins will allow each to be resolved using the same laser Question 2 1 / 1 pts Gel filtration chromatography is one method to purify proteins that can be used to generate either monoclonal or polyclonal antibodies. What is the most likely reason this is a good method to purify proteins? Proteins can easily be purified by charge and size when coated with SDS Proteins can be centrifuged through a column and pellet at specific speeds Correct! Proteins will separate by size going through the column beads and their holes Organelles containing the protein will have a specific buoyancy and separate in a gradient Antibodies can be used to detect the protein on a western blot https://canvas.eee.uci.edu/courses/40270/quizzes/187689 2/14 11/27/21, 2:14 PM Midterm Exam 1: BIO SCI D103 LEC A: CELL BIOLOGY (05530) Question 3 1 / 1 pts Monoclonal antibodies are generated for their specificity to part of an antigen. The antigen is injected into the mouse, the spleen is subsequently removed, and spleen cells are fused to myeloma cells to produce hybridomas for antibody production. What would most likely be the consequence if the blood of the mouse was used to purify antibodies instead? Blood cells fused to myeloma cells produce less antibodies than spleen cells Correct! Mouse blood contains polyclonal antibodies that will recognize different parts of the antigen Mouse blood does not contain antibodies, only spleen cells contain antibodies Mouse blood will contain too many antibodies that cannot be selectively purified There is no difference between antibodies from the blood or from hybridomas, only the ability to produce more antibodies from hybridomas Question 4 https://canvas.eee.uci.edu/courses/40270/quizzes/187689 0 / 1 pts 3/14 11/27/21, 2:14 PM Midterm Exam 1: BIO SCI D103 LEC A: CELL BIOLOGY (05530) What is the best reason to use direct immunofluorescence (IF) over indirect IF? Direct IF can use either monoclonal or polyclonal antibodies orrect Answer Direct IF reduces the noise, or non-specific signal, over indirect IF Direct IF requires polyclonal antibodies to work Direct IF increases the sensitivity of signal over indirect IF ou Answered Direct IF requires monoclonal antibodies to work Question 5 0 / 1 pts What is the most likely reason sphingomyelinase can quickly respond to a toxin that facilitates calcium entry into the cell? ou Answered Sphingomyelinase is recruited to the membrane by specific phospholipids Sphingomyelinase activates a calcium pump to remove excess calcium from the cytoplasm Clathrin and retromer coated systems allow the endosome system to be replenished by the Golgi orrect Answer Regulated secretory pathway https://canvas.eee.uci.edu/courses/40270/quizzes/187689 4/14 11/27/21, 2:14 PM Midterm Exam 1: BIO SCI D103 LEC A: CELL BIOLOGY (05530) Constitutive secretory pathway Question 6 0 / 1 pts What is the most likely reason a cell changes lipid composition of membranes? To respond to changes in the external environment To promote vesicle budding orrect Answer All of the answers are correct To recruit cargo to a particular portion of the membrane ou Answered To promote endocytosis Question 7 1 / 1 pts Nucleotide transport (exchange of ATP and ADP) within the inner mitochondrial membrane occurs down their concentration gradients. How would nucleotide exchange most likely be affected upon addition of nonhydrolyzable ATP? Nucleotides would not bind to their transporter Nucleotides would bind to the transporter, but would not enter the mitochondria https://canvas.eee.uci.edu/courses/40270/quizzes/187689 5/14 11/27/21, 2:14 PM Correct! Midterm Exam 1: BIO SCI D103 LEC A: CELL BIOLOGY (05530) Nucleotide transport would not be significantly affected Nucleotides would bind to the transporter, but would not leave the mitochondria Question 8 1 / 1 pts The sodium-potassium pump uses ATP hydrolysis to pump ions against their concentration gradient. If the plasma membrane was disrupted and the ion concentration was equilibrated on either side of the membrane, how would this likely change the properties of the pump? Sodium ions would be locked inside the pump Sodium ions could not enter the pump Correct! The properties would not change and the pump would function normally The pump would bind ATP but would not need to hydrolyze ATP to function The pump would no longer need ATP to function Question 9 0 / 1 pts Which points on the curve of an action potential would most likely change the most if potassium voltage gated channels turned off by time instead of voltage? https://canvas.eee.uci.edu/courses/40270/quizzes/187689 6/14 11/27/21, 2:14 PM Midterm Exam 1: BIO SCI D103 LEC A: CELL BIOLOGY (05530) Points A and B ou Answered Points D and E orrect Answer Points C and D Points B and C None of the points would be affected Question 10 https://canvas.eee.uci.edu/courses/40270/quizzes/187689 0 / 1 pts 7/14 11/27/21, 2:14 PM Midterm Exam 1: BIO SCI D103 LEC A: CELL BIOLOGY (05530) How would addition of a drug that blocks ATP synthase alter the proton gradient in the mitochondrial intermembrane space? ATP production would stop Protons will continue to move freely across the outer and inner mitochondrial membranes orrect Answer Protons will still pump into the intermembrane space, but can only escape through the outer mitochondrial membrane Protons will no longer be pumped into the intermembrane space ou Answered Protons will still pump into the intermembrane space, but cannot escape without a functioning ATP synthase Question 11 0 / 1 pts ATP can be generated by oxidative phosphorylation in mitochondria through the respiratory chain, which is composed of a series of hydrogen pumps, electron carriers, and ATP synthase within the inner mitochondrial membrane (IMM). Which of the following best describes how the outer mitochondrial membrane (OMM) functions in this process? orrect Answer The OMM allows free diffusion of ADP and ATP into and out of the intermembrane space https://canvas.eee.uci.edu/courses/40270/quizzes/187689 8/14 11/27/21, 2:14 PM Midterm Exam 1: BIO SCI D103 LEC A: CELL BIOLOGY (05530) Electrons are generated in the OMM and transferred to the IMM ou Answered Protons are kept inside the intermembrane space without the ability to diffuse across the OMM Protons are pumped into the intermembrane space from the cytoplasm 1 / 1 pts Question 12 ER import requires Partially translated protein ; mitochondrial import requires [ Select ] [ Select ] ; nuclear import requires . Answer 1: Correct! Partially translated protein Answer 2: Correct! Fully translated and unfolded protein Answer 3: Correct! Fully translated and folded protein Question 13 https://canvas.eee.uci.edu/courses/40270/quizzes/187689 0 / 1 pts 9/14 11/27/21, 2:14 PM Midterm Exam 1: BIO SCI D103 LEC A: CELL BIOLOGY (05530) What would most likely occur to nuclear import if the GTPase Activating Protein of RAN was ACTIVATED by a drug? orrect Answer Nuclear import would still occur and cargo would be released The importin complex would not form The importin-protein complex would not interact with the nuclear pore ou Answered Cargo would not be released from the importin complex Proteins with an NLS sequence would not bind the importin complex Question 14 1 / 1 pts Energy is necessary for import of proteins into the mitochondrion. How would import of mitochondrial proteins most likely be affected if the proton pumps were ACTIVATED by addition of a drug without affecting ATP levels? None of the answers are appropriate Proteins would not refold within the mitochondria Proteins would not enter the TIM complex Proteins would not enter the TOM complex Correct! Protein import into the matrix would not be affected https://canvas.eee.uci.edu/courses/40270/quizzes/187689 10/14 11/27/21, 2:14 PM Midterm Exam 1: BIO SCI D103 LEC A: CELL BIOLOGY (05530) Question 15 1 / 1 pts What would most likely be the cause if a cell secretes a higher number of misfolded proteins into the extracellular space? Gain of BiP chaperone Excessive dimerization of IRE1 Gain of glucosyl transferase Correct! Loss of calnexin Loss of eIF2alpha Question 16 0 / 1 pts If a transmembrane protein contained four transmembrane domains where the two internal loops were facing the extracellular space, where would the positive charges around the first and last transmembrane domains be found? ou Answered Carboxy-terminal side of the first and amino-terminal side of the last Amino-terminal side of the first and amino-terminal side of the last Carboxy-terminal side of the first and carboxy-terminal side of the last orrect Answer Amino-terminal side of the first and carboxy-terminal side of the last There would be no positive charges next to the transmembrane domains https://canvas.eee.uci.edu/courses/40270/quizzes/187689 11/14 11/27/21, 2:14 PM Midterm Exam 1: BIO SCI D103 LEC A: CELL BIOLOGY (05530) Question 17 0 / 1 pts You have discovered a novel soluble protein that contains a NES, a SRP start transfer sequence, and a mitochondrial localization signal sequence. What would be the most likely destination of the protein if the mitochondrial localization signal sequence was removed? orrect Answer The protein would be secreted from the cell The protein would be retained in the ER ou Answered The protein would stay in the cytoplasm The protein would localize to the mitochondria The protein would be retained in the nucleus Question 18 1 / 1 pts How would the immediate loss of ATP likely influence the delivery of uncoated vesicles to their target membrane? Recycling of Rab-GTPase would not occur Vesicles would not fuse with their target membrane Vesicles would not tether to their target membrane Correct! Vesicles delivery would not be affected https://canvas.eee.uci.edu/courses/40270/quizzes/187689 12/14 11/27/21, 2:14 PM Midterm Exam 1: BIO SCI D103 LEC A: CELL BIOLOGY (05530) Vesicles would not dock with their target membrane Question 19 0 / 1 pts Immediate loss of the Sar1 GTPase activating protein would most likely influence which of the following processes? Cargo binding to the receptor orrect Answer Coat disassembly Outer coat recruitment ou Answered Inner coat recruitment Sar1 integrating into the membrane Question 20 1 / 1 pts You express an enzyme in a cell that localizes to the plasma membrane and catalyzes the conversion of PI(4,5)P2 to PI(4)P. What would most likely happen to clathrin-mediated endocytosis? Correct! AP2 would not localize to the membrane and dynamic would not pinch off the forming vesicle Dynamin would not pinch off the forming vesicle https://canvas.eee.uci.edu/courses/40270/quizzes/187689 13/14 11/27/21, 2:14 PM Midterm Exam 1: BIO SCI D103 LEC A: CELL BIOLOGY (05530) Cargo would not bind its receptor AP2 would not localize to the membrane Clathrin-mediated endocytosis would go on as normal Quiz Score: 9 out of 20 https://canvas.eee.uci.edu/courses/40270/quizzes/187689 14/14