Quiz 12: The Endomembrane System

In which of the following organelles would you expect to first find a protein destined to be secreted from a cell? A)endosome B)Golgi apparatus C)lysosome D)secretory vesicle E)endoplasmic reticulum

The endoplasmic reticulum is a site for A)potassium storage in muscle cells. B)drug detoxification by catalase. C)N-linked glycosylation of polypeptides. D)addition of lipid residues. E)degradation of foreign material brought into the cell by phagocytosis.

Comparing cells synthesizing secretory proteins and cells secreting steroid hormones,the cells synthesizing the steroid hormones have A)more rough ER. B)more smooth ER. C)equal amounts of smooth and rough ER. D)equal amounts of smooth and rough ER,but more lysosomes. E)equal amounts of smooth and rough ER,but fewer lysosomes.

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

The continuous release of mucus by the epithelial cells lining the respiratory tract is an example of A)regulated secretion. B)constitutive secretion. C)the mucus response. D)clathrin-coated pit formation. E)phagocytosis.

When a membrane protein is radioactively labeled during synthesis and followed through the various organelles in the secretory pathway,all the radioactivity is concentrated in the cis-Golgi apparatus six hours after the protein synthesis.This suggests that the protein A)was imported directly into the cis-Golgi posttranslationally. B)contains a KDEL sequence near its C-terminus. C)has a membrane-spanning domain length equals the thickness of the cis-Golgi membrane. D)has a mannose-6-phosphate tag. E)is misfolded and being degraded in the cis-Golgi.

The vesicles that are anchored to the plasma membrane at a nerve cell presynaptic site are specialized for A)constitutive secretion. B)regulated secretion. C)polarized secretion. D)lysosome secretion. E)endocytosis.

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.

In receptor-mediated endocytosis,each of the following is a fate for the receptors and/or vesicle contents except A)transcytosis. B)digestion in a lysosome. C)recycling to the plasma membrane. D)release from the vesicle into the nucleus. E)All are possible fates.

Each of the following is a lysosomal storage disease caused by a deficiency in lysosomal enzymes except A)familial hypercholesterolemia. B)Hurler syndrome. C)Hunter syndrome. D)type II glycogenosis. E)Tay-Sachs disease.

Each of the following is part of the core oligosaccharide side chain in the ER except A)N-acetyl glucosamine. B)erythrose. C)mannose. D)glucose. E)All are part of the core oligosaccharide.

Peroxisomes A)are not derived from the endoplasmic reticulum. B)are bounded by double membranes. C)possess acid phosphatase activity. D)possess mannose phosphotransferase activity. E)exist only in algae and photosynthetic cells in plants.

Which of the following organelles has the ability to catabolize alkanes found in oil and petroleum products? A)mitochondria B)smooth endoplasmic reticulum C)peroxisomes D)lysosomes E)late endosomes

A protein that is N-glycosylated is expected to be A)secreted from the cell. B)retained in the endoplasmic reticulum. C)localized in the Golgi body. D)imported into a cell by endocytosis. E)a peroxisome enzyme.

Each of the following is an endoplasmic reticulum function except A)addition of carbohydrate to proteins to make glycoproteins. B)peptide folding. C)the assembly of multimeric proteins. D)the export of protein that cannot be folded into the cytoplasm for destruction. E)All are endoplasmic reticulum functions.

Total internal reflection (TIRF)microscopy is best used to visualize fluorescently labeled protein activity A)that is too small to see with regular light microscopy. B)on the upper surface of a cell. C)in the Golgi. D)on the lower surface of a cell. E)in the nucleus.

Which of the following is associated with extracellular digestion caused by release of the lysosomes enzymes into the environment? A)Tay-Sachs disease B)rheumatoid arthritis C)autophagy D)Hunter syndrome E)Hurler syndrome

Each of the following organelles is part of the endomembrane system except A)the peroxisome. B)the Golgi complex. C)the smooth endoplasmic reticulum. D)the endosome. E)the rough endoplasmic reticulum.

Each of the following is true about botulinum toxin (Botox)except A)The toxin is one of the most potent toxins known. B)Botox is a SNARE protein. C)It can be used therapeutically to stop muscle spasms. D)It has been used to remove wrinkles caused by muscle contractions. E)It has potential use as a migraine headache treatment.

You have isolated two fractions containing similar-sized vesicles by centrifugation.You suspect one fraction contains lysosomes and the other contains peroxisomes.To confirm that a fraction contains peroxisomes,you would assay for which of the following enzymes? A)acid phosphatase B)β-glucuronidase C)ribonuclease D)a protease E)catalase

On which of the following intracellular locations does clathrin organize a coat and form vesicles? A)lysosomes B)trans-Golgi complex C)endoplasmic network D)inner membrane of mitochondria E)regulated secretory vesicles

Each of the following is a component involved in the SNARE hypothesis model mechanism except A)v-SNARE. B)Rab GTPase. C)tethering complex. D)NSF protein. E)All are involved.

In a lysosomal storage disease,newly synthesized lysosome hydrolases are secreted from the cells rather than being delivered to the lysosomes.What is one possible mechanism for this result? A)The cis-Golgi network lacks a proton gradient. B)The ER is unable to produce lysosomal vesicles. C)Lysosomal enzymes are not phosphorylated in the rER. D)Mannose is not phosphorylated in the cis-Golgi network. E)All the hydrolase genes are mutated,resulting in synthesis by ribosomes free in the cytoplasm rather than on the endoplasmic reticulum membrane.

Pancreatic acinar cells produce and store hydrolytic enzymes in zymogen granules until hormones signal the cell to release the enzymes in a process known as A)transport secretion. B)regulated secretion. C)constitutive secretion. D)intracellular secretion. E)consistent secretion.

Which of the following techniques would be best used to measure the strength of a v-SNARE-t-SNARE interaction? A)X-ray crystallography B)TIRF microscopy C)GFP fusion proteins D)optical tweezers E)radioactive pulse labeling

Using genetic engineering techniques,which of the following would you do to a protein that normally is constitutively secreted to make it accumulate in the ER? A)fuse it to GFP B)add an amino acid that would get a mannose-6-phosphate group added to its carbohydrate C)add a KDEL sequence near its C-terminus D)mutate one of the asparagines that is normally glycosylated to an alanine,which is not glycosylated E)None of these would cause the protein to accumulate in the ER.

Which of the following proteins requires GTP in the process of LDL receptor-mediated endocytosis? A)LDL receptor B)dynamin C)AP-2 complex D)uncoating enzyme E)clathrin

Each of the following is part of the endomembrane system,except A)Golgi complex. B)endosomes. C)lysosomes. D)peroxisomes. E)zymogen granules.

A protein that is normally localized in the cytoplasm has been engineered so that it will be secreted from the cell instead.Which of the following represents the most likely pathway for the protein after it has been completely synthesized? A)rER → Golgi → secretory vesicle → environment B)rER → Golgi → sER → cytoplasm → environment C)cytoplasm → rER → Golgi → secretory vesicle → environment D)sER → Golgi → secretory vesicle → environment E)rER → secretory vesicle → Golgi → environment

Sorting of hormones into regulated secretory vesicles in the trans-Golgi network involves A)mannose-6-phosphorylation. B)formation of large aggregates. C)a KDEL receptor. D)a zymogen granule receptor. E)O-linked glycosylation

In animal cells,oxidation of very long fatty acids occurs in A)mitochondria. B)peroxisomes. C)lysosomes. D)the smooth endoplasmic reticulum. E)residual bodies.

Which of the following cell types would be associated with the greatest concentration of low-density lipoproteins (LDLs)? A)skin B)muscle C)connective tissue D)blood E)liver

Uptake of low-density lipoproteins (LDLs)occurs by A)simple diffusion. B)phagocytosis. C)facilitated transport. D)receptor-mediated endocytosis. E)pinocytosis.

The low pH of lysosomes is established by A)acid hydrolases. B)ATP-dependent proton pumps. C)β-glucuronidases. D)catalases. E)superoxide dismutases.

The plant cell organelle most analogous to animal cell lysosomes is the A)vacuole. B)glyoxysome. C)microsome. D)endosome. E)leaf peroxisome.

The plant cell organelle most analogous to the animal cell endosome is the A)provacuole. B)lysosome. C)peroxisome. D)glyoxysome. E)None of the above are analogous.

A COPII-coated vesicle has all of the following except A)Sec 13/31. B)Sec 23/34. C)v-SNARE. D)Sar1. E)AP-2.

Which of the following cellular processes may be inhibited in tumor cells? A)autophagy B)N-linked glycosylation C)caveolae uptake D)LDL degradation E)catalase activity

The ________ is the organelle involved in the post-translational modification of proteins and sorting of proteins to various intracellular and secretory compartments.

The ________ is the organelle that fuses with endosomes and supplies hydrolytic enzymes necessary for the digestion of the materials.

________ is the triskelion molecule that forms the coats on vesicles associated with receptor-mediated endocytosis.

________ is the organelle associated with the functions of steroid biosynthesis,carbohydrate metabolism,and drug detoxification.

________ pump protons to keep the internal proton concentration of lysosomes high.

Exocytosis is stimulated by regional increases in cytoplasmic ________ concentration.

________ bind specific receptors to clathrin in receptor-mediated endocytosis vesicles.

V- and t-________ mediate final docking between vesicle and target membranes.

The movement of proteins and lipids from the ER to their appropriate locations within a cell is known as ________.

The chronic use of the ________ class of drugs can increase liver detoxifying enzymes that decrease the effectiveness of antibiotics,anticoagulants,and steroids.

Coated vesicles known as ________ may be associated with redox sensing.

If you presented two substances-(1)LDL particles and (2)large aggregates of 'foreign' macromolecules-to a mixture of cells,which uptake mechanism would you expect the cells to use to ingest each substance? What distinguishes the uptake mechanisms?

Design an experiment that will allow you to follow a protein from its synthesis to constitutive secretion from the cell.Where would you expect to find the protein at different times during the process? How would the pathway differ if the protein obtained a mannose-6-phosphate modification during transit?

Explain the mechanism by which the fungal toxin brefeldin A affects retrieval of KDEL-tagged proteins from the cis-Golgi network back to the endoplasmic reticulum.

Peroxisomes and the smooth endoplasmic reticulum are both associated with detoxification of harmful substances.How do these two organelles differ with regard to this process?

Describe how low concentrations of Botox can be used as a treatment for wrinkles and muscle spasms.