MCB TEST 3 UPDATED ACTUAL Questions and CORRECT Answers
Question: cytosol has a ph of
Correct Answer: 7
Question: what is the pH of the intermembrane space
Correct Answer: 7-> cytosol has same pH as the intermembrane space
Question: how does a mitochondrial protein get into the matrix of the mitochondria and properly get folded
-what if it needs extra help -energy source?
Correct Answer: -chaperones help it go through , TOM and TIM keep the protein unfolded until it makes
it to the matrix -if need more help you use chaperonins -need ATP (use 3 or 4 depending on if you need
chaperonins) -and a proton gradient
Question: proteins synthesized in the golgi go to
Correct Answer: -RER -lysosome -exported/membrane
Question: proteins synthesized in the cytoplasm go to
Correct Answer: -mitochondria -nucleus -peroxisomes -chloroplasts -stay in cytoplasm
Question: preproteins
Correct Answer: not translocated in teh ER
Question: pre lysosymes
Correct Answer: not in ER yet
Question: signal sequence for protein that has to go in the ER 3 domains
Correct Answer: -N terminal positive -central hydrophobic -c terminal polar
Question: starting point cytoplasm, ending point nucleus -location and type of signal -key characteristics of
signal
Correct Answer: -cytoplasm, NLS -basic/positively charge, often includes proline
Question: starts nucleus-> ends in cytoplasm -location and type -characteristics
Correct Answer: -cytoplasm, NES -leucine rich signal
Question: starts in cytoplasm, ends in ER -location and type -characteristics
Correct Answer: -signal sequence in the RER -hydrophobic amino acids
Question: starts in RER ends in Golgi -location and type -characteristics
Correct Answer: -11 mer, RER -sugar/carbohydrate, branched chain of sugars
Question: golgi to lysosome -location and type -characteristics
Correct Answer: -6th mannose of the 11th mer -hydrophobic amino acids, branched chain of sugars
Question: cytoplasm to mitochondria -location and type -characteristics
Correct Answer: --mitochondrial transit sequence, starts in cytoplasm -part of transported protein at amino
terminus -basic/positively charged amino acids
, Question: if an e coli cell makes one mistake during DNA replication, how many mistakes is that same cell
likely to make if its DNA polymerases do not proofread? -if no mismatch repair system?? -if it was lacking
both of them??
Correct Answer: -100 -100 10,000 (multiply 100 * 100)
Question: why are errors in transcription more frequent than errors in DNA replication??
Correct Answer: -no proofreading/mismatch repair in RNA
Question: why are errors in transcription less critical than errors in DNA replication?-
Correct Answer: -make multiple copies of RNA< if make bad one can send it to a lysosome to degrade
Question: why is the semipermeability of phospholipid bilayers essential for lysosomal function?
Correct Answer: -lysosome=ph 5 -ATP dependent proton pump -if membrane was permeable all protons
would come out-> why we have a membrane that does not let charged things come out!
Question: protein P was recently characterized as an exclusively large protein of 120 kDa that does not
have a NLS. propose a mechanism by which protein P is recruited to the nucleus.
Correct Answer: -more than 40 can't get through -bind / attach to something that has an NLS-> shuttle
protein
Question: protein p was shown to have a NES and an RNA binding domain. Propose a role for protein P.
how could you reconcile the fact that protein P has an NES but is only detected in the nucleus
Correct Answer: -goes to cytoplasm then goes right back to the nucleus due to dissociation
Question: cells can internalize foreign material by phagocytosis. however, when the foreign material
cannot be degraded, like asbestos fibers, it accumulates in one type of organelle within the cell cytoplasm.
explain
Correct Answer: -lysosomes: can't degrade asbestos-> accumulates-> lysosome with eventually rupture->
bad for you
Question: in intestinal tracks of mammals, specialized epithelial cells secrete large quantities of digestive
enzymes. which organelle would you expect to be very prominent in these cells?
Correct Answer: rough ER
Question: secreted proteins are usually about 20 amino acids longer when they are synthesized by free
fibosomes in a test tube. yet, free ribosomes function identically to membrane bound ribosomes. what
hypothesis can you propose to explain this experimental observation
Correct Answer: -in the cell the peptidase in the ER that clears off an amino sequence, thats not in teh test
tube
Question: cytosolic stays cytosolic lumenal stays lumenal
Correct Answer: ---
Question: Fluorescent in situ hybridization (FISH)
Correct Answer: • Microscopy technique o DNA probes labeled with fluorescent dye o Looks like one dot
on the chromosome that's showing up
Question: chromosome painting
Correct Answer: paints entire chromosome a different color
Question: cytosol has a ph of
Correct Answer: 7
Question: what is the pH of the intermembrane space
Correct Answer: 7-> cytosol has same pH as the intermembrane space
Question: how does a mitochondrial protein get into the matrix of the mitochondria and properly get folded
-what if it needs extra help -energy source?
Correct Answer: -chaperones help it go through , TOM and TIM keep the protein unfolded until it makes
it to the matrix -if need more help you use chaperonins -need ATP (use 3 or 4 depending on if you need
chaperonins) -and a proton gradient
Question: proteins synthesized in the golgi go to
Correct Answer: -RER -lysosome -exported/membrane
Question: proteins synthesized in the cytoplasm go to
Correct Answer: -mitochondria -nucleus -peroxisomes -chloroplasts -stay in cytoplasm
Question: preproteins
Correct Answer: not translocated in teh ER
Question: pre lysosymes
Correct Answer: not in ER yet
Question: signal sequence for protein that has to go in the ER 3 domains
Correct Answer: -N terminal positive -central hydrophobic -c terminal polar
Question: starting point cytoplasm, ending point nucleus -location and type of signal -key characteristics of
signal
Correct Answer: -cytoplasm, NLS -basic/positively charge, often includes proline
Question: starts nucleus-> ends in cytoplasm -location and type -characteristics
Correct Answer: -cytoplasm, NES -leucine rich signal
Question: starts in cytoplasm, ends in ER -location and type -characteristics
Correct Answer: -signal sequence in the RER -hydrophobic amino acids
Question: starts in RER ends in Golgi -location and type -characteristics
Correct Answer: -11 mer, RER -sugar/carbohydrate, branched chain of sugars
Question: golgi to lysosome -location and type -characteristics
Correct Answer: -6th mannose of the 11th mer -hydrophobic amino acids, branched chain of sugars
Question: cytoplasm to mitochondria -location and type -characteristics
Correct Answer: --mitochondrial transit sequence, starts in cytoplasm -part of transported protein at amino
terminus -basic/positively charged amino acids
, Question: if an e coli cell makes one mistake during DNA replication, how many mistakes is that same cell
likely to make if its DNA polymerases do not proofread? -if no mismatch repair system?? -if it was lacking
both of them??
Correct Answer: -100 -100 10,000 (multiply 100 * 100)
Question: why are errors in transcription more frequent than errors in DNA replication??
Correct Answer: -no proofreading/mismatch repair in RNA
Question: why are errors in transcription less critical than errors in DNA replication?-
Correct Answer: -make multiple copies of RNA< if make bad one can send it to a lysosome to degrade
Question: why is the semipermeability of phospholipid bilayers essential for lysosomal function?
Correct Answer: -lysosome=ph 5 -ATP dependent proton pump -if membrane was permeable all protons
would come out-> why we have a membrane that does not let charged things come out!
Question: protein P was recently characterized as an exclusively large protein of 120 kDa that does not
have a NLS. propose a mechanism by which protein P is recruited to the nucleus.
Correct Answer: -more than 40 can't get through -bind / attach to something that has an NLS-> shuttle
protein
Question: protein p was shown to have a NES and an RNA binding domain. Propose a role for protein P.
how could you reconcile the fact that protein P has an NES but is only detected in the nucleus
Correct Answer: -goes to cytoplasm then goes right back to the nucleus due to dissociation
Question: cells can internalize foreign material by phagocytosis. however, when the foreign material
cannot be degraded, like asbestos fibers, it accumulates in one type of organelle within the cell cytoplasm.
explain
Correct Answer: -lysosomes: can't degrade asbestos-> accumulates-> lysosome with eventually rupture->
bad for you
Question: in intestinal tracks of mammals, specialized epithelial cells secrete large quantities of digestive
enzymes. which organelle would you expect to be very prominent in these cells?
Correct Answer: rough ER
Question: secreted proteins are usually about 20 amino acids longer when they are synthesized by free
fibosomes in a test tube. yet, free ribosomes function identically to membrane bound ribosomes. what
hypothesis can you propose to explain this experimental observation
Correct Answer: -in the cell the peptidase in the ER that clears off an amino sequence, thats not in teh test
tube
Question: cytosolic stays cytosolic lumenal stays lumenal
Correct Answer: ---
Question: Fluorescent in situ hybridization (FISH)
Correct Answer: • Microscopy technique o DNA probes labeled with fluorescent dye o Looks like one dot
on the chromosome that's showing up
Question: chromosome painting
Correct Answer: paints entire chromosome a different color
