Cell Phys: Chapter 12

31) 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.

B) peroxisomes.

24) 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.

B) regulated secretion.

17) 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

B) rheumatoid arthritis

21) 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

B) trans-Golgi complex

2) 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.

C) N-linked glycosylation of polypeptides.

26) 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.

C) add a KDEL sequence near its C-terminus

4) 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

C) clathrin

6) 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.

C) has a membrane-spanning domain length equals the thickness of the cis-Golgi membrane

36) 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) provacuole.

29) 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

A) rER → Golgi → secretory vesicle → environment

14) 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.

A) secreted from the cell.

18) 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.

A) the peroxisome.

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

A) vacuole.

2) 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.

A) are not derived from the endoplasmic reticulum.

38) 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

A) autophagy

10) 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.

A) familial hypercholesterolemia.

19) 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.

B) Botox is a SNARE protein.

5) 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.

B) constitutive secretion.

27) 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

B) dynamin

11) 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.

B) erythrose.

30) 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

B) formation of large aggregates.

3) 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.

B) more smooth ER

13) 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

C) peroxisomes

7) 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.

C) polarized secretion

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

C) β-glucuronidases.

8) 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.

23) 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.

D) Mannose is not phosphorylated in the cis-Golgi network.

16) 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.

D) on the lower surface of a cell

25) 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

D) optical tweezers

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

D) peroxisomes.

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

D) receptor-mediated endocytosis

9) 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.

D) release from the vesicle into the nucleus.

37) 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.

E) AP-2.

15) 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.

E) All are endoplasmic reticulum functions.

22) 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.

E) All are involved.

20) 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

E) catalase

1) 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

E) endoplasmic reticulum

32) 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

E) liver