32 Questions
Where do nearly all proteins begin their synthesis?
Ribosomes in the cytosol
What contains the active site of the ribosome for creating new peptide bonds?
Large subunit
What is the main pathway for protein secretion in cells?
RER → Golgi → Vesicles → Membrane
Where do new proteins go from the ribosome in the cytosol to reach the organelle where they function?
By using sorting signals in their amino acid sequence
Which organelle has a netlike labyrinth of branching tubules and flattened sacs?
Endoplasmic reticulum
What is the main function of the smooth endoplasmic reticulum?
Biosynthesis and metabolism of lipids
Which proteins are responsible for preventing protein misfolding and aggregation in the ER?
Hsp70/BiP
What is the role of calnexin in protein folding in the ER?
Binds to monoglucosylated or incompletely folded proteins
What is the function of OST (oligosaccharyltransferase) in N-linked glycosylation?
Adds N-linked oligosaccharide to proteins
Which component guides the ER signal sequence to the ER membrane?
Signal-recognition particle (SRP)
Which organelle is responsible for protein glycosylation by adding a common N-linked oligosaccharide?
Endoplasmic reticulum
What is the core of the translocator in the ER called?
Sec61 complex
Which enzyme removes the final glucose residue if protein folding is good?
GlsII
What is the role of ERp57 in protein folding in the ER?
Adding disulfide bonds
What is the function of PDI (Protein disulfide-isomerase) in the ER?
Forms disulfide bonds
What is the main function of the rough endoplasmic reticulum?
Synthesizing proteins and glycosylating them
Where do nearly all proteins, except a few inside mitochondria and plastids, begin their synthesis?
Ribosomes in the cytosol
What is the main pathway for protein secretion in cells?
RER → Golgi → Vesicles → Membrane
What organelle is responsible for protein glycosylation by adding a common N-linked oligosaccharide?
Golgi apparatus
What is the function of OST (oligosaccharyltransferase) in N-linked glycosylation?
Translocates proteins into the ER lumen
Which component guides the ER signal sequence to the ER membrane?
Signal-recognition particle (SRP)
What is the main function of calnexin in protein folding in the ER?
Binds to monoglucosylated or incompletely folded proteins
What is the function of OST (oligosaccharyltransferase) in N-linked glycosylation?
Adds a common N-linked oligosaccharide to proteins
What is the role of ERp57 in protein folding in the ER?
Adds disulfide bonds to proteins
What is the main function of the smooth endoplasmic reticulum?
Lipid biosynthesis and metabolism
Where do nearly all proteins begin their synthesis?
Cytosol
What contains the active site of the ribosome for creating new peptide bonds?
Large subunit
What is the core of the translocator in the ER called?
Sec61 complex
What is the main pathway for protein secretion in cells?
Cotranslational import into the ER
What is the role of PDI (Protein disulfide-isomerase) in the ER?
Adds disulfide bonds to proteins
What is the function of Hsp70/BiP in protein folding in the ER?
Prevents protein misfolding and aggregation
What is the function of Gls (Glucosidase) in N-linked glycosylation?
Removes glucose from properly folded proteins
Test your knowledge of protein sorting in the endoplasmic reticulum with this quiz. Explore the processes involved in protein synthesis and the role of ribosomes in ensuring accurate pairing of codons and anticodons. Challenge yourself with questions related to the structure and function of ribosomal subunits and the catalytic site.
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