BIOL 4100 EXAM 2 QUESTIONS AND ANSWERS WITH COMPLETE
SOLUTIONS GRADED A++
makes use of membrane bound protein complexes to directly move specific
proteins from one compartment to a topographically different compartment
transmembrane transport
name the mitochondrial subcompartment:
-have cristae invaginations
-only protein, no complexes, no pores
-only allows active transport
inner mitochondrial membrane
name the mitochondrial subcompartment:
-lipid bilayer
-has pores and protein complexes
outer mitochondrial membrane
name the mitochondrial subcompartment:
-topographically similar to cytoplasm because of pores
intermembrane space
name the mitochondrial subcompartment:
-location of mitochondrial DNA
mitochondrial matrix
T/F: the mitochondrial matrix and the intermembrane space are topographically
similar
,F
name the mitochondrial subcompartment:
-invaginations in the inner mitochondrial membrane
cristae
where is the mitochondrial localization signal located on the ribosome after
translation? what are MLS used for? what do they bind to?
first 20 peptides (at N terminus) that come out of ribosome after translation, used for
proteins that come off ribosome and are not free in the cytoplasm, chaperones
mitochondrial localization signals
-__________ proteins
-positively charged _____________ alpha helix
-directs precursor proteins to the ______ or _______ of the mitochondria
-usually cleaved from the _______ upon maturation in the mitochondrial
compartment
precursor, amphipathic, inner membrane or matrix, maturation
describe the test that found that Beta barrel proteins are targeted to mitochondria
by a dedicated beta hairpin element
YFP (protein with a hairpin bond, also shows fluorescence) was cleaved and half was
bound to TOM, when the other half of the protein with the hairpin was allowed close to
the mitochondrial membrane, fluorescence was seen
T/F: though it is common for alpha helices to be present at the N terminus of
MLSs, it is not required for functionality
T
,describe the process for chaperones for mitochondrially targeted proteins
preprotein acts with cytosol chaperones (normally HSP70 family); preprotein/chaperone
leave MLS available to interact with TOM receptor as they move through the cytoplasm;
general import port (inside of TOM) uses ATP to allow MLS to start feeding preprotein
though
why do the TOM proteins not allow much folding in a protein trying to feed
through them?
the pore is very small
what are the 3 common mitochondrial translocation complexes? what are their 3
main functions?
TOM, TIM23, TIM22; receptor recognition, channel conductance, force for vectorial
movement
how many times can channel conductance occur?
2
what are the Tom proteins involved in the TOM complex? where does translocase
with TOM take place?
Tom40, 22, 5,6,7, 70, 20; outer membrane (into mitochondria)
name the TOM complex protein:
-channel forming protein and main component of the TOM complex of the OMM
essential for import of protein precursor
-form quaternary structure once 3 of these have come together
Tom40
, name the TOM complex protein:
-functions as the transit peptide receptor of the TOM complex, accepting
precursor proteins from the TOM70 and TOM20 receptors
TOM22
name the 3 TOM complex protein:
-regulate the assembly and stability of the TOM complex
TOM5,6,7
name the TOM complex protein:
-receptor responsible for the recognition and translocation of chaperone assisted
precursor proteins through the TOM complex of the OMM
-preproteins without MLS; chaperones have MLS
TOM70
name the TOM complex protein:
-receptor responsible for the recognition and translocation of presequence
containing proteins through the TOM complex of the OMM
-preproteins have LMS
TOM20
what are the TIM proteins involved in the TIM23 complex? where does
translocase with TIM23 take place?
Tim23, 17, 44, Ssc1p, Yge1p, Tim50; inner mitochondrial membrane
name the 2 TIM23 complex protein:
-essential component of the TIM23 complex, that mediates the translocation of
presequence containing proteins across the IMM
SOLUTIONS GRADED A++
makes use of membrane bound protein complexes to directly move specific
proteins from one compartment to a topographically different compartment
transmembrane transport
name the mitochondrial subcompartment:
-have cristae invaginations
-only protein, no complexes, no pores
-only allows active transport
inner mitochondrial membrane
name the mitochondrial subcompartment:
-lipid bilayer
-has pores and protein complexes
outer mitochondrial membrane
name the mitochondrial subcompartment:
-topographically similar to cytoplasm because of pores
intermembrane space
name the mitochondrial subcompartment:
-location of mitochondrial DNA
mitochondrial matrix
T/F: the mitochondrial matrix and the intermembrane space are topographically
similar
,F
name the mitochondrial subcompartment:
-invaginations in the inner mitochondrial membrane
cristae
where is the mitochondrial localization signal located on the ribosome after
translation? what are MLS used for? what do they bind to?
first 20 peptides (at N terminus) that come out of ribosome after translation, used for
proteins that come off ribosome and are not free in the cytoplasm, chaperones
mitochondrial localization signals
-__________ proteins
-positively charged _____________ alpha helix
-directs precursor proteins to the ______ or _______ of the mitochondria
-usually cleaved from the _______ upon maturation in the mitochondrial
compartment
precursor, amphipathic, inner membrane or matrix, maturation
describe the test that found that Beta barrel proteins are targeted to mitochondria
by a dedicated beta hairpin element
YFP (protein with a hairpin bond, also shows fluorescence) was cleaved and half was
bound to TOM, when the other half of the protein with the hairpin was allowed close to
the mitochondrial membrane, fluorescence was seen
T/F: though it is common for alpha helices to be present at the N terminus of
MLSs, it is not required for functionality
T
,describe the process for chaperones for mitochondrially targeted proteins
preprotein acts with cytosol chaperones (normally HSP70 family); preprotein/chaperone
leave MLS available to interact with TOM receptor as they move through the cytoplasm;
general import port (inside of TOM) uses ATP to allow MLS to start feeding preprotein
though
why do the TOM proteins not allow much folding in a protein trying to feed
through them?
the pore is very small
what are the 3 common mitochondrial translocation complexes? what are their 3
main functions?
TOM, TIM23, TIM22; receptor recognition, channel conductance, force for vectorial
movement
how many times can channel conductance occur?
2
what are the Tom proteins involved in the TOM complex? where does translocase
with TOM take place?
Tom40, 22, 5,6,7, 70, 20; outer membrane (into mitochondria)
name the TOM complex protein:
-channel forming protein and main component of the TOM complex of the OMM
essential for import of protein precursor
-form quaternary structure once 3 of these have come together
Tom40
, name the TOM complex protein:
-functions as the transit peptide receptor of the TOM complex, accepting
precursor proteins from the TOM70 and TOM20 receptors
TOM22
name the 3 TOM complex protein:
-regulate the assembly and stability of the TOM complex
TOM5,6,7
name the TOM complex protein:
-receptor responsible for the recognition and translocation of chaperone assisted
precursor proteins through the TOM complex of the OMM
-preproteins without MLS; chaperones have MLS
TOM70
name the TOM complex protein:
-receptor responsible for the recognition and translocation of presequence
containing proteins through the TOM complex of the OMM
-preproteins have LMS
TOM20
what are the TIM proteins involved in the TIM23 complex? where does
translocase with TIM23 take place?
Tim23, 17, 44, Ssc1p, Yge1p, Tim50; inner mitochondrial membrane
name the 2 TIM23 complex protein:
-essential component of the TIM23 complex, that mediates the translocation of
presequence containing proteins across the IMM
