Question

please answer all that you can

1. You have genetically engineered green fluorescent protein (GFP) containing a KDEL sequence (GFP-KDEL). When GFP-KDEL is expressed in normal human fibroblasts and examined using fluorescence microscopy, the fluorescence appears diffuse across the cytoplasm. How would you explain this observations given that KDEL is supposed to be an ER-specific sorting sequence? A. This engineered GFP would not have a hydrophobic signal sequence to get it into the RER in the first place. B. The KDEL sequence would not be recognized because the protein is not in the right compartment. C. This engineered GFP would be synthesized on cytosolic ribosomes. Both A and B. A, B and C. 2. Hannah is studying a candidate chaperone protein that is approximately 55 kDa. Analysis of the protein’s primary structure reveals a C-terminal KDEL sequence. Based on this information, along with the results of the experiment below in which cellular fractions (nucleus, N; cytoplasm, C; rough ER, R; Golgi, G) were analyzed by western blot for the presence of this protein, Hannah concludes that the chaperone is a soluble resident ER protein. Her labmate Julian, however, strongly disagrees with Hannah and says that there is no way the protein could be a resident ER chaperone. Who is right, and why? Hannah, because the band in the Golgi sample is weak compared to that in the ER. Neither Hannah nor Julian has come to the correct conclusion. Hannah, because this would be expected for any resident ER protein since some of it might be lost as vesicles move to the Golgi. Julian, because of the band in the Golgi sample. Julian, because soluble resident ER proteins have a KKXX signal. 3. In eukaryotic cells, sugar residues are covalently attached to proteins in the process of N-linked glycosylation, a posttranslational modification that occurs _____. in the cytoplasm. at the plasma membrane. in the rough ER. in the Golgi apparatus. in the nucleus. 4. The presence of clathrin mediates vesicular transport _____. the nuclear membrane to an endosome. the cis-Golgi to the trans-Golgi. the trans-Golgi to a lysosome. from the ER to the cis-Golgi. the plasma membrane to trans-Golgi. 5. Mannose 6-phosphate is an important residue, as it is required to target soluble enzymes to the lysosome. The enzymes responsible for attaching this residue onto these soluble enzymes reside in the _____. medial-Golgi. cis-Golgi. rough ER. cytosol. trans-Golgi. 6. Tay-Sachs disease is a rare inherited disorder that progressively destroys nerve cells in the brain and spinal cord. Tay–Sachs disease is caused by insufficient activity of the enzyme hexosaminidase A (a vital hydrolytic enzyme), which in turn results in the failure of lipids being broken down. Which cellular organelle is most likely to be directly involved in this disease? Golgi apparatus. Lysosome. Smooth ER. Rough ER. Peroxisome. 7. Microvilli are present on the apical surface of epithelia that function in absorption of solutes, such as the lining of the intestine and wall of the kidney tubule. As schematized in the illustration below, actin filaments support the microvilli of the epithelial cell. Each microvillus contains about 25 actin filaments that are maintained in a highly ordered arrangement by villin and fimbrin. To which class of actin-binding proteins do villin and fimbrin belong? End-blocking. Bundling. Filament-severing. Actin-filament depolymerizing. Monomer-polymerizing. 8. Dynamic assembly and disassembly of a cytoplasmic microtubule in a cell occurs primarily at its plus end, because its minus end is usually anchored to _____. a microtubule organizing center. a catastrophin. the plasma membrane. a centromere. the mitochondrial outer membrane. 9. Which region of myosin interacts with actin filaments? The motor domain. The stalk domain. The light chains. The tail domain. The lever domain. 10. Which of the following statements does not accurately describe Kinesin-1? Kinesin-1 transports vesicles along microtubules. Kinesin-1 contains two head groups. Kinesin-1 is a minus (-) end-directed motor. Kinesin-1 binds and hydrolyzes ATP to produce movement. Each of the statements above accurately describes Kinesin-1. 11. Cancer is a group of diseases involving abnormal cell growth with the potential to invade or spread to other parts of the body. Vinblastine is a chemotherapy medication used to treat some forms of cancer, including non-small cell lung cancer, bladder cancer, brain cancer and melanoma. Vinblastine inhibits microtubule polymerization. Cancer cells given vinblastine would be unable to _____. separate chromosomes during cell division. maintain a spherical nucleus. form microvilli. extend lamellipodia to facilitate crawling. undergo cytokinesis.

Answer 1

5: Cis golgi:

Cis golgi has the enzyme responsible for attaching mannose -6 phosphate residue onto soluble enzymes.

6: Rough ER:

Since the Tay-Sachs disease is due to absence of enzymes, rough ER is involved. Rough ER bears ribosomes on its surface which are the site for protein synthesis. And enzymes are proteins.