48 Questions
Where are nuclear, mitochondrial, and peroxisomal proteins synthesized?
On free ribosomes in the cytoplasm
Which organelles are associated with the proteins synthesized on ribosomes bound to the endoplasmic reticulum (RER)?
Endoplasmic reticulum and Golgi complex
What is the function of the signal sequence in protein synthesis?
It directs the ribosome to the endoplasmic reticulum (ER)
What is the role of the Signal Recognition Particle (SRP) in protein synthesis?
It binds to the signal sequence and directs the ribosome to the ER
Where are SRP receptors located and what is their function in protein synthesis?
On the cytoplasmic side of the endoplasmic reticulum; they bind specifically to SRP
What is the function of SRP receptors in relation to protein synthesis?
To attach the entire ribosome to the endoplasmic reticulum (ER)
During protein synthesis in the ER, which process involves the transfer of sugar from dolichol lipid to new protein?
N-glycosylation
Where do proteins move after being synthesized in the ER?
Golgi
Which organelle contains acid hydrolyase enzymes and is tagged by mannose-6-P for recognition by TGN receptors?
Lysosomes
What is the final sorting and packing region for new lysosomal proteins before they bud off as transport vesicles?
TGN
Which process involves proteins being continuously secreted outside the cell?
Constitutive secretion
What is required for nuclear proteins to enter the nucleus?
Nuclear localization signals (NLS)
Which complex do mitochondrial proteins pass through to enter the mitochondria?
TOM and TIM complexes
What is the role of v-SNARE proteins in protein transport from the ER to the Golgi?
Mediate fusion with the Golgi complex
What process involves the tagging of lysosomal proteins for recognition by TGN receptors?
Mannose-6-P tagging
What is the main function of the TGN (trans-Golgi network) in protein processing?
Sorting and packing new lysosomal proteins
Which organelle is responsible for the continuous secretion of proteins outside the cell?
Endoplasmic reticulum
What is the function of importin in the process of nuclear protein entry into the nucleus?
Binding to nuclear localization signals (NLS)
What is the specific sequence (N-terminal) on a new protein during the translation process, which is recognized and bound to the Signal Recognition Particle (SRP)?
Signal sequence
Where are proteins that will be associated with the endoplasmic reticulum (ER), Golgi complex, and plasma membrane synthesized?
Cytoplasm on free ribosomes
What is the function of the Signal Recognition Particle (SRP) receptor in the process of protein synthesis?
Attaching the ribosome to the endoplasmic reticulum (ER)
What is the translocation complex, which serves as a pore for the passage of proteins into the lumen of the endoplasmic reticulum (ER)?
Permease
Where are nuclear, mitochondrial, and peroxisomal proteins synthesized?
Cytoplasm on free ribosomes
Where are proteins that will eventually be associated with membranes or secreted from the cell synthesized?
On ribosomes bound to the endoplasmic reticulum
What is the name of the specific sequence at the N-terminus of a new protein during the translation process, which is recognized and bound to the Signal Recognition Particle (SRP)?
Signal sequence
Which organelle contains acid hydrolyase enzymes and is tagged by mannose-6-P for recognition by TGN receptors?
Lysosomes
What is the function of the SRP receptor in relation to protein synthesis?
Attachment of the ribosome to the endoplasmic reticulum
What is the main function of the trans-Golgi network (TGN) in protein processing?
Sorting and packing of lysosomal proteins
Where do nuclear, mitochondrial, and peroxisomal proteins undergo synthesis?
Cytoplasm on free ribosomes
What organelle is responsible for the sorting and packing of new lysosomal proteins before they bud off as transport vesicles?
Golgi complex
What is the specific sequence recognized for the transfer of sugar from dolichol lipid to new protein during protein synthesis in the ER lumen?
Asn-X-Thr
Which proteins are continuously secreted outside the cell?
Constitutive secretion proteins
Where do free ribosomes synthesize proteins for cytosol, nucleus, mitochondria, or peroxisomes?
Cytosol
During protein synthesis in the ER, what is the specific sequence recognized for the transfer of sugar from dolichol lipid to new protein?
The specific sequence recognized for the transfer of sugar from dolichol lipid to new protein during protein synthesis in the ER lumen is Asn-X-Ser and Asn-X-Thr.
What is the main function of the trans-Golgi network (TGN) in protein processing?
The main function of the trans-Golgi network (TGN) in protein processing is serving as the final sorting and packing region, where new lysosomal proteins bind to receptors and bud off as transport vesicles, fusing with endosomes to form functional lysosomes.
What is required for nuclear proteins to enter the nucleus?
Nuclear proteins require nuclear localization signals (NLS) to enter the nucleus, binding to importin and moving through the nuclear pore complex.
Which complex do mitochondrial proteins pass through to enter the mitochondria?
Mitochondrial proteins require chaperones to enter mitochondria, binding to import sequence and moving through TOM and TIM complexes.
What is the function of the Signal Recognition Particle (SRP) in protein synthesis?
The function of the Signal Recognition Particle (SRP) in protein synthesis is to recognize and bind to the N-terminal signal sequence of a new protein, targeting the ribosome-mRNA complex to the endoplasmic reticulum (ER) membrane.
What is the process that involves proteins continuously secreted outside the cell?
The process that involves proteins continuously secreted outside the cell is constitutive secretion.
Where do free ribosomes synthesize proteins for cytosol, nucleus, mitochondria, or peroxisomes?
Free ribosomes synthesize proteins for cytosol, nucleus, mitochondria, or peroxisomes in the cytoplasm.
Which organelle contains acid hydrolyase enzymes and is tagged by mannose-6-P for recognition by TGN receptors?
Lysosomes contain acid hydrolyase enzymes and are tagged by mannose-6-P for recognition by TGN receptors.
Where are nuclear, mitochondrial, and peroxisomal proteins synthesized?
In the cytoplasm on free ribosomes.
What is the specific sequence (N-terminal) called, which directs the ribosome to the ER during the translation process?
Signal sequence (N-terminal).
What is the function of the Signal Recognition Particle (SRP) receptor in the process of protein synthesis?
It specifically binds to the SRP, attaching the entire ribosome to the ER.
What is the name of the translocation complex that serves as a pore through which the protein passes into the lumen of the ER as translation and elongation proceed?
Translocation complex.
Where are proteins synthesized that will eventually be associated with the endoplasmic reticulum, the Golgi complex, and the plasma membrane, or secreted from the cell?
On ribosomes bound to the endoplasmic reticulum (RER).
What is the specific sequence at the N-terminus of a new protein during the translation process, which is recognized and bound to the Signal Recognition Particle (SRP)?
Signal sequence (N-terminal).
What is the function of the SRP receptor in relation to protein synthesis?
It specifically binds to the SRP, attaching the entire ribosome to the ER.
Study Notes
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Protein synthesis ends, ribosomes release from ER, signal sequence is cleaved, and protein moves to correct membrane
-
Protein modifications occur during synthesis in ER lumen through cotranslational process, including N-glycosylation
-
Glycosylation involves transfer of sugar from dolichol lipid to new protein, specifically on Asn-X-Ser and Asn-X-Thr sequences
-
Golgi is the sorting organelle, proteins are sent there after ER, with some remaining and others moving onward to lysosomes or outside cell
-
Proteins move from ER to Golgi via transport vesicles, fusion with Golgi complex is mediated by v-SNARE proteins
-
Lysosomes contain acid hydrolyase enzymes, tagged by mannose-6-P for recognition by TGN receptors
-
TGN is the final sorting and packing region, new lysosomal proteins bind to receptors and bud off as transport vesicles, fusing with endosomes to form functional lysosomes
-
Constitutive secretion involves proteins continuously secreted outside the cell, while regulated secretion occurs only with external stimulus
-
Free ribosomes synthesize proteins for cytosol, nucleus, mitochondria, or peroxisomes, which are tagged for specific organelle entry
-
Nuclear proteins require nuclear localization signals (NLS) to enter nucleus, binding to importin and moving through nuclear pore complex
-
Mitochondrial proteins require chaperones to enter mitochondria, binding to import sequence and moving through TOM and TIM complexes.
-
Protein synthesis ends, ribosomes release from ER, signal sequence is cleaved, and protein moves to correct membrane
-
Protein modifications occur during synthesis in ER lumen through cotranslational process, including N-glycosylation
-
Glycosylation involves transfer of sugar from dolichol lipid to new protein, specifically on Asn-X-Ser and Asn-X-Thr sequences
-
Golgi is the sorting organelle, proteins are sent there after ER, with some remaining and others moving onward to lysosomes or outside cell
-
Proteins move from ER to Golgi via transport vesicles, fusion with Golgi complex is mediated by v-SNARE proteins
-
Lysosomes contain acid hydrolyase enzymes, tagged by mannose-6-P for recognition by TGN receptors
-
TGN is the final sorting and packing region, new lysosomal proteins bind to receptors and bud off as transport vesicles, fusing with endosomes to form functional lysosomes
-
Constitutive secretion involves proteins continuously secreted outside the cell, while regulated secretion occurs only with external stimulus
-
Free ribosomes synthesize proteins for cytosol, nucleus, mitochondria, or peroxisomes, which are tagged for specific organelle entry
-
Nuclear proteins require nuclear localization signals (NLS) to enter nucleus, binding to importin and moving through nuclear pore complex
-
Mitochondrial proteins require chaperones to enter mitochondria, binding to import sequence and moving through TOM and TIM complexes.
-
Protein synthesis ends, ribosomes release from ER, signal sequence is cleaved, and protein moves to correct membrane
-
Protein modifications occur during synthesis in ER lumen through cotranslational process, including N-glycosylation
-
Glycosylation involves transfer of sugar from dolichol lipid to new protein, specifically on Asn-X-Ser and Asn-X-Thr sequences
-
Golgi is the sorting organelle, proteins are sent there after ER, with some remaining and others moving onward to lysosomes or outside cell
-
Proteins move from ER to Golgi via transport vesicles, fusion with Golgi complex is mediated by v-SNARE proteins
-
Lysosomes contain acid hydrolyase enzymes, tagged by mannose-6-P for recognition by TGN receptors
-
TGN is the final sorting and packing region, new lysosomal proteins bind to receptors and bud off as transport vesicles, fusing with endosomes to form functional lysosomes
-
Constitutive secretion involves proteins continuously secreted outside the cell, while regulated secretion occurs only with external stimulus
-
Free ribosomes synthesize proteins for cytosol, nucleus, mitochondria, or peroxisomes, which are tagged for specific organelle entry
-
Nuclear proteins require nuclear localization signals (NLS) to enter nucleus, binding to importin and moving through nuclear pore complex
-
Mitochondrial proteins require chaperones to enter mitochondria, binding to import sequence and moving through TOM and TIM complexes.
-
Protein synthesis ends, ribosomes release from ER, signal sequence is cleaved, and protein moves to correct membrane
-
Protein modifications occur during synthesis in ER lumen through cotranslational process, including N-glycosylation
-
Glycosylation involves transfer of sugar from dolichol lipid to new protein, specifically on Asn-X-Ser and Asn-X-Thr sequences
-
Golgi is the sorting organelle, proteins are sent there after ER, with some remaining and others moving onward to lysosomes or outside cell
-
Proteins move from ER to Golgi via transport vesicles, fusion with Golgi complex is mediated by v-SNARE proteins
-
Lysosomes contain acid hydrolyase enzymes, tagged by mannose-6-P for recognition by TGN receptors
-
TGN is the final sorting and packing region, new lysosomal proteins bind to receptors and bud off as transport vesicles, fusing with endosomes to form functional lysosomes
-
Constitutive secretion involves proteins continuously secreted outside the cell, while regulated secretion occurs only with external stimulus
-
Free ribosomes synthesize proteins for cytosol, nucleus, mitochondria, or peroxisomes, which are tagged for specific organelle entry
-
Nuclear proteins require nuclear localization signals (NLS) to enter nucleus, binding to importin and moving through nuclear pore complex
-
Mitochondrial proteins require chaperones to enter mitochondria, binding to import sequence and moving through TOM and TIM complexes.
Test your knowledge about the synthesis and localization of proteins in the cell. Learn about the differences between proteins synthesized on free ribosomes and those synthesized on ribosomes bound to the endoplasmic reticulum.
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