BIO 130 -VERSION44

BIO 130 -VERSION44 1. What interactions provide structure for the plasma membrane? a. Membrane proteins organise the lipids in the bilayer through interactions between amino acid side chains. b. Lipids organise the membrane proteins on the surface of the bilayer through interactions between lipid hydrocarbon tails and water. c. Hydrophobic lipids provide the basic structure of the membrane through interactions with water. d. Amphipathic lipids provide the basic structure of the membrane through interactions with water. 2. Which location will have the FEWEST number of phosphatidylcholine molecules? a. The exoplasmic face of the Golgi apparatus. b. The side of the plasma membrane facing the outside of the cell. c. The endoplasmic reticulum membrane leaflet facing the lumen. d. The cytosolic face of vesicle membranes. 3. Which of the following proteins MOST likely corresponds to the hydropathy plot shown below? (“START” refers to an ER signal sequence which is a start transfer sequence, “++” refers to a positively charged amino acid region, “--“ refers to a negatively charged amino acid region.) 4. Which of the following statements BEST describes the structure of most membrane spanning domains in the integral membrane proteins of eukaryotic cells? a. A rolled up beta-sheet of 20-30 amino acids with mainly hydrophobic side chains. b. An alpha-helix of 20-30 amino acids with mainly hydrophobic side chains. c. An amphipathic alpha-helix of 20-30 amino acids. d. A rolled up beta-sheet of 20-30 amino acids with mainly hydrophobic side chains in contact with membrane lipids and hydrophilic side chains lining the pore. 5. In the laboratory you are observing the effect of temperature on membrane phospholipids. You conduct an experiment in which you incubate the same type of bacteria at two different temperatures. Sample 1 was incubated at 20 ˚C. Sample 2 was incubated at 40 ˚C. What do you expect to find when you compare the phospholipids from each sample? a. Sample 1 will have more saturated phospholipids that also contain shorter hydrocarbon tails. b. Sample 1 will have more unsaturated phospholipids that also contain longer hydrocarbon tails. c. Sample 2 will have more unsaturated phospholipids that also contain shorter hydrocarbon tails. d. Sample 2 will have more saturated phospholipids that also contain longer hydrocarbon tails. 6. Which of the following corresponds to the CORRECT order from most hydrophilic to least hydrophilic? a. A GPI-anchored protein; a single pass transmembrane protein; a mature secreted protein; the Na+/K+ pump. b. The Na+/K+ pump; a GPI-anchored protein; a single pass transmembrane protein; a mature secreted protein. c. A mature secreted protein; a GPI-anchored protein; a single pass transmembrane protein; the Na+/K+ pump. d. A GPI-anchored protein; a single pass transmembrane protein; the Na+/K+ pump; a mature secreted protein. 7. Which of the following statements concerning transport proteins is CORRECT? a. All transport proteins bind to solutes and exhibit a dramatic conformational change during transport. b. All active transport proteins require ATP. c. All channel proteins perform facilitated diffusion. d. All transporter proteins perform active transport. 8. You are manipulating transport proteins in a Na+-filled artificial liposome. There is a supply of H+, ADP, and Pi outside of the liposome. Which of the following would result in the generation of the largest amounts of ATP? a. A Na+/H+ exchanger that transports Na+ out of the lipsome and an F-type ATPase with its ATP binding domain facing the outside of the liposome. b. A Na+/H+ exchanger that transports Na+ out of the lipsome and an ABC transporter with its ATP binding domain facing the outside of the liposome. c. A Na+/H+ symporter that transports Na+ into the lipsome and a V-type ATPase with its ATP binding domain facing the outside of the liposome. d. A Na+/H+ symporter that transports Na+ out of the lipsome and an F-type ATPase with its ATP binding domain facing the outside of the liposome. 9. Which of the following is a similarity between actin filaments and microtubules? a. They both have polarity. b. They both hydrolyze ATP. c. They are both made up of heterodimers. d. They are both anchored on centrosomes. 10. Which of the following scenarios would you expect to disrupt the transport of glucose from the lumen of the intestine to the blood stream? a. A higher concentration glucose in the cytosol of intestinal epithelial cells compared with the blood stream. b. Increased activity of the Na+/K+ pump at the basolateral membrane of the intestinal epithelial cells. c. K+ leak channels in the basolateral membrane of intestinal epithelial cells. d. A lower concentration of Na+ in the lumen of the intestine compared to the cytosol of intestinal epithelial cells. 11. Which two proteins have the greatest role in establishing the resting membrane potential of animal cell plasma membranes? a. Na+/K+ pump and K+ leak channels. b. K+ co-transporters and the Na+/K+ pump. c. Na+ co-transporters and Na+ leak channels. d. The V-type ATPase and H+ co-transporters. 12. Which of the following mutations would you expect to affect transmission of a signal across a nerve synapse? a. A mutation in voltage gated Ca2+ channels. b. A mutation in kinesin. c. A mutation in acetylcholine receptors. d. All of the above. 13. Acid hydrolases in the lumen of the lysosome break down proteins into individual amino acids. These proteases require the acidic environment in the lysosome lumen. Amino acids generated in the lysosome lumen must be transported across the lysosome membrane into the cytosol. You measure the concentration of amino acids in the cytosol and discover that this concentration is five times higher than the concentration in the lumen of the lysosome. Which of the following proteins is MOST likely to be responsible for transporting amino acids out of the lysosome? a. An amino acid channel b. An amino acid uniporter c. A H+/amino acid antiporter d. A H+/amino acid symporter 14. Pancreatic cells have been treated with a translation initiation inhibitor. After 30 min (when all previous translation has been completed), where would the majority of the ribosomes be located? a. Golgi only. b. RER and cytosol. c. RER only. d. Cytosol only. 15. Which of the following describes the likely movement of a protein, from the start of translation to its final destination? a. nucleus, cytosol, endoplasmic reticulum, Golgi apparatus, lysosomes, outside of the cell. b. cytosol, endoplasmic reticulum, peroxisome. c. endoplasmic reticulum, Golgi apparatus, mitochondrion. d. cytosol, nucleus. 16. If the signal sequence of an extracellular matrix protein is mutated which of the following would be MOST likely to occur? a. The protein would remain in the cytosol and would be larger than the protein secreted from normal cells. b. The protein would remain in the cytosol and would be smaller than the protein secreted from normal cells. c. The protein would remain associated with the translocon and would be smaller than the protein secreted from normal cells. d. The protein would remain associated with the translocon and would be larger than the protein secreted from normal cells. 17. You design an experiment that allows you to label newly synthesized lipids and trace their path through the cell. Which of the following movements of labelled lipids are you MOST likely to observe? a. Label at the rough endoplasmic reticulum followed by the Golgi apparatus and then secretory vesicles. b. Label at the plasma membrane followed by early endosomes and then the smooth endoplasmic reticulum. c. Label at the smooth endoplasmic reticulum followed by the Golgi apparatus and then secretory vesicles. d. Label at the plasma membrane followed by early endosomes and then the rough endoplasmic reticulum. 18. Immediately after the process of endocytosis, glycosylated lipids in the exoplasmic leaflet will be found to have . a. their glycosylated hydrophobic head groups facing the lysosome lumen. b. their glycosylated polar head groups facing the early endosome lumen. c. their glycosylated polar head groups facing the cytosol. d. their glycosylated hydrophobic tails facing the cytosol. 19. How are intermediate filaments different from microtubules? a. Only intermediate filaments hydrolyze a nucleoside triphosphate. b. Only intermediate filaments have motor proteins. c. Only intermediate filaments are absent from plant cells. d. Only intermediate filaments form dimers. 20. A protein transmembrane segment is found to have a more negative charge towards the amino-terminal end of the protein and a more positive charge towards the carboxy-terminal end of the protein. Which of the following statements is MOST likely to be true for this protein? a. If the protein is a plasma membrane receptor, the carboxy-terminal end will be found in the extracellular environment. b. If the protein is an acid hydrolase, it will be found in the late endosome membrane with its amino- terminal end glycosylated. c. If the protein is resident in the endoplasmic reticulum membrane, the amino-terminal end will be found in the cytosol. d. If the protein is a V-type ATPase, it will be found in the lysosome lumen. 21. In animal cells, microtubules are continually growing and shrinking due to . a. dynamic instability at the minus end b. dynamic instability at the plus end c. the interactions of actin and myosin d. All of the above 22. Which of the following proteins would be MOST likely to carry a collagen filled vesicle from the Golgi apparatus towards the plasma membrane? a. Kinesin b. Actin c. Dynein d. Myosin 23. Which of the following proteins would be MOST likely to aid in the transfer of vesicles from the endoplasmic reticulum to the Golgi apparatus? a. Kinesin b. Actin c. Dynein d. Myosin 24. Which of the following techniques would you use if you wanted to investigate the organization of individual microtubules in the cilia of a paramecium? a. Fluorescence recovery after photobleaching b. Electron microscopy c. Immunofluorescence and light microscopy d. A pulse chase experiment 25. Which of the following best describes a structure and its subunits? a. Cell walls are composed of intermediate filaments. b. Plasmodesmata are composed of phospholipids. c. Adhesion belts are composed of claudins and occludins. d. Sealing strands are composed of cadherins. 26. Two cells are linked by a single gap junction. How many transmembrane domains make up this link? a. 48 b. 24 c. 12 d. 6 27. Your research has determined that a gastrointestinal disease is caused by the failure of intestinal epithelial cells to locate transport proteins to the apical membrane within the cell. Which of the following two genes would be MOST likely to contain a mutation? Genes coding for…. a. occludin and a gap junction protein. b. integrin and a microfilament motor protein. c. plectin and laminin. d. claudin and a microtubule motor protein. 28. Connective tissues are held together by . a. the interaction between cells and the extracellular matrix. b. gap junctions. c. tight junctions. d. desmosomes.