Organelles
Which of the following organelles is not part of the endomembrane system?
a. Golgi apparatus
b. the endosome
c. mitochondria
d. lysosomes
Mitochondria
Characteristic that is typical of a nuclear localization signal
possession of positively charged (basic) amino acids
Movement of material or proteins from the Golgi apparatus to the ER is called
retrograde transport
A patient presents with a genetic disease in which the enzyme Protein Disulfide Isomerase (PDI) is secreted into the extracellular space instead of being found in its normal location as a resident Rough ER (RER) protein. You sequence the secreted protein and find that the normal sequence Lys (K), Asp (D), Glu (E), Leu (L) near the C-terminus is mutated to Lys, Asp, Phe, Leu. Explain why the patient secretes PDI
the mutation caused the loss of the RER retention sequence and the PDI is not recycle to the ER
Which of the following is NOT a process that delivers material to the lysosome?
a. pinocytosis
b. phagocytosis
c. transcytosis
d. autophagy
Transcytosis
In which cellular location would you expect to find ribosomes translating mRNAs that encode ribosomal proteins?
a. the nucleus
b. on the rough ER
c. in the cytosol
d. in the lumen of the ER
In the cytosol
This allows the Epidermal Growth Factor Receptor (EGFR) to enter the nucleus
Nuclear Localization Sequence
Your friend has just joined a lab that studies vesicle budding from the Golgi and has been given a cell line that does not form mature vesicles. He wants to start designing some experiments but was not listening carefully when he was told about the molecular defect of this cell line. He is too embarrassed to ask and comes to you for help. He does recall that this cell line forms coated pits but vesicle budding and the removal of coat proteins don’t happen. Which of the following proteins might be lacking in this cell line?
a. clathrin
b. Rab
c. dynamin
d. adaptin
Dynamin
The first organelle you'd expect to find a protein that is destined to be secreted from a cell.
Rough endoplasmic reticulum
Which of the following statements is false regarding phagocytosis?
A) It can ingest large particles.
B) It involves the projection of pseudopods.
C) It is used by amoebae to ingest food.
D) It is mediated by clathrin at the plasma membrane.
E) It is used by macrophages and neutrophils to ingest bacteria.
D) It is mediated by clathrin at the plasma membrane.
The proteins of bacteria were radioactively labeled and subsequently fed to mammalian phagocytic cells. The proteins within the phagocytic cell became increasingly more radioactive over time. This observation is the result of the activity of
Lysosomes
The absence of any signal or targeting sequence, where would you expect any protein to be located in the cell
Cytosol
Which of the following protein families are NOT involved in directing transport vesicles to the target membrane?
a. SNAREs
b. Rabs
c. tethering proteins
d. adaptins
Adaptins
Name the sequence of organelles that reflects the locations that a secretory protein will visit on its way from its production site to its secretion out of the cell
rough ER, cis-Golgi, medial-Golgi, trans-Golgi
Which of the following molecules forms the coat during receptor-mediated endocytosis-coated pit formation?
A) mannose-6-phosphate
B) T-SNARE
C) clathrin
D) tethering protein
E) caveolin
clathrin
Ribosomal DNA clusters and rRNA gather together to form this cellular structure?
nucleolus
Proteins targeted to the mitochondria contain an N-terminal targeting sequence that is
amphipathic (hydrophillic and hydrophobic)
Molecules to be packaged into vesicles for transport are selected by
a. clathrin.
b. adaptins.
c. dynamin.
d. SNAREs.
adaptins
Oligosaccharide-protein transferase is found in the ___________, and transfers an oligosaccharide comprised of 9 mannose, 2-N-acetyl-glucosamine, and 3 glucose residues from _________ to __________.
Rough ER…….dolichol………..asparagnine
Which of the following is not true for clathrin:
is formed by triskelions, is important in receptor-mediated endocytosis, contains both clathrin heavy chains and light chains, is important in phagocytosis, concentrates the receptor-ligands at the cell surface before endocytosis
is important in phagocytosis
The enzyme responsible for removing the phosphate group from glucose-6-phosphate generating glucose that is released to the bloodstream and its localization
Glucose-6-Phosphatase in the Smooth Endoplasmic Reticulum (SER) membrane
A patient presents with a genetic disease in which the enzyme Protein Disulfide Isomerase (PDI) is secreted into the extracellular space instead of being found in its normal location as a resident Rough ER (RER) protein. You sequence the secreted protein and find that the normal sequence Lys (K), Asp (D), Glu (E), Leu (L) near the C-terminus is mutated to Lys, Asp, Phe, Leu. Explain why the patient secretes PDI
The mutation caused the loss of the RER retention sequence and the PDI is not recycle to the ER
Which of the following statements about vesicular membrane fusion is FALSE?
a. Membrane fusion does not always immediately follow vesicle docking.
b. The hydrophilic surfaces of membranes have water molecules associated with them that must be displaced before vesicle fusion can occur.
c. The GTP hydrolysis of the Rab proteins provides the energy for membrane fusion.
d. The interactions of the v-SNAREs and the t-SNAREs pull the vesicle membrane and the target organelle membrane together so that their lipids can intermix.
c. The GTP hydrolysis of the Rab proteins provides the energy for membrane fusion.
An individual with I-cell disease has a defect in lysosomal targeting of many of the lysosomal targeted hydrolytic enzymes produced by cells. I-cell disease results from a defective phosphotransferase that is needed to add mannose-6-phosphate to oligosaccharide chains on lysosomal enzymes. As a result these individuals have psychomotor retardation, skeletal abnormalities, and a life span of about 8 years. If the proteins are not targeted to the lysosome, where do they go?
the proteins are secreted from cells
During receptor-mediated endocytosis, the acidification of the vesicle (drop in pH) has this function
Causes the receptor-ligand interaction to be disrupted