how is the N-terminus of the polypeptide modified to become a mature protein? - Answer-removal of the N-formyl group from N-fMet
______ are proteins that correct misfolding and suppress incorrect folding as the protein comes out of the E site of rRNA - Answer-chaperones
_____ is a chaperone t...
MCB 3020 - Exam 2 (Chapters 11, 13, 16,
17, 19) Questions and Answers
how is the N-terminus of the polypeptide modified to become a mature protein? -
Answer-removal of the N-formyl group from N-fMet
______ are proteins that correct misfolding and suppress incorrect folding as the protein
comes out of the E site of rRNA - Answer-chaperones
_____ is a chaperone that associates w the ribosome and masks hydrophobic regions
so they don't fold with each other prematurely - Answer-trigger factor
______ is a chaperone that helps iron-sulfur centers obtain their iron atom - Answer-
DnaJ/DnaK/GrpE
_____ is a chaperone that forms a cage for misfolded proteins to be uncoiled and
refolded, away from cytoplasmic crowding - Answer-GroES/GroEL
______ and _____ are chaperones that are cytoplasmic and require ATP - Answer-
DnaJ/DnaK/GrpE and GroES/GroEL
_____ is when proteins are moved from the cytoplasm to/across the plasma membrane
- Answer-translocation
protein ____ refers to the movement of proteins from the cytoplasm to the external
environment - Answer-secretion
the ____ system is the name for the general secretion pathway - Answer-Sec
the ____ -terminal is the signal peptide/sequence - Answer-N
____ (SRP) is a protein-RNA complex that surveys actively translating ribosomes and
will escort the entire ribosome to the membrane. It looks for membrane proteins with
really hydrophobic signal peptides - Answer-signal recognition particle
the alternative route to the membrane is via the _____ protein - Answer-SecA
the _____ system is another translocation route that will only secrete folded proteins -
Answer-Tat
the 3 main translocation systems for gram-positive and gram-negative bacteria are: -
Answer-Sec
SRP
Tat
,after polypeptide translocation, the two final maturation steps are - Answer-1) signal
peptidase removing the signal peptide
2) protein disulfide isomerase (PDI) forming disulfides
_____ is the enzyme that removes the signal peptidee - Answer-signal peptidase
_____ (PDI) is the enzyme that oxidizes cysteine residues to form disulfides - Answer-
protein disulfide isomerase
____ is a second signal that some proteins have at the C-terminus that directs them to
sortase enzymes embedded in the membrane - Answer-sorting signal
_____ is an enzyme that catalyzes the rxn btw the sorting signal and Lipid II, the
peptidoglycan precursor - Answer-sortase
_____ is the peptidoglycan precursor - Answer-Lipid II
protein secretion in gram-______ bacteria requires crossing 2 membranes - Answer-
negative
secreted proteins that cause host injury are called _____ - Answer-effectors
the 3 two-step secretion systems involved in protein secretion in gram-negative cells
are: - Answer-1) type 5
2) type 2
3) type 9
type 2 secretion systems are only found in _____ - Answer-proteobacteria
type 9 secretion systems are only found in ____ - Answer-bacteroidetes
the 5 one-step secretion systems involved in protein secretion in gram-negative cells
are: - Answer-1) type 1
2) type 3
3) type 4
4) type 6
5) type 7
proteins exported by the type ___ secretion system (a one-step system) pass through
an ATP binding cassette, a membrane fusion protein, and a barrel protein - Answer-1
the type ___ secretion system is a one-step system that works as a molecular syringe -
Answer-3
, the type ___ secretion system is a one-step system that is used for DNA transfer, that
works at the cell poles, using integral membrane proteins, ATPases, and a pilus -
Answer-4
the type ____ secretion system is a one-step system that is a contractile weapon used
by bacteria to deliver toxins to neighboring cells, whether bacterial or eukaryotic -
Answer-6
the type ____ secretion system is a one-step system that is found in Mycobacterium
spp. despite that being a gram-positive bacterium. this ss gives important virulence
factors to host cells. it has roles in DNA transfer, cell envelope integrity, sporulation,
metal uptake, and competition for nutrients - Answer-7
________ (OMVs) are made of a lipid bilayer of outer membrane + lipopolysaccharide
and integral outer membrane proteins. the lumen contains molecules found in the
periplasm. these are ONLY FOUND in gram-NEGATIVE bacteria - Answer-outer
membrane vesicles
_____ (EVs) are vesicles that pinch off the plasma membrane and have to cross a thick
peptidoglycan cell wall. these are ONLY FOUND in gram-POSITIVE bacteria - Answer-
extracellular membrane vesicles
_____ initiates the formation of the replication bubble - Answer-DnaA
____ is a protein involved in termination of transcription - Answer-rho
_____ is the subunit/factor on the replisome that recognizes the promoter region -
Answer-sigma factor
the Shine-Dalgarno sequence is found on the _____ - Answer-mRNA
_____ binds to the initiation complex first (translation) - Answer-IF-3
the protein that promotes translation termination is called _____ - Answer-release factor
genes that encode housekeeping functions and are needed almost always are called
_____ - Answer-housekeeping genes
genes that are expressed continuously are called _____ - Answer-constitutive genes
an ______ enzyme is one whose level rises in the presence of a small effector molecule
called an inducer - Answer-inducible
many catabolic enzymes are _____ enzymes - Answer-inducible
many anabolic enzymes are ____ enzymes - Answer-repressible
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