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BL1020 Ch 5 Exam Latest
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The lipid layer that forms the foundation of cell membranes is primarily composed of molecules called __________. A. phospholipids B. fats C. proteins D. carbohydrates - Answer A. phospholipids While water continually orients phospholipids into a lipid bilayer, it does not fix the lipids permanently into position. Thus, the bilayer is considered to be _______. A. static B. fluid C. fluctuating D. charged - Answer B. fluid What is the net movement of substances to regions of lower concentration called? A. Osmosis B. Active transport C. Facilitation D. Diffusion - Answer D. Diffusion Osmosis is the diffusion of water across a membrane in response to the concentration of one or more of the ______. A. solutes B. membranes C. compartments D. cells - Answer A. solutes Which type of proteins is embedded in the cell membrane in both active transport and
facilitated transport? A. carrier B. cytoskeletal C. structural D. targeted - Answer A. carrier Osmosis occurs as water can cross the lipid bilayer through specialized channels for water movement called ________________. A. proteins B. transmembrane carbohydrates C. membrane pores D. aquaporins - Answer D. aquaporins The plasma membrane is a thin sheet of lipid embedded with A. proteins. B. carbohydrates. C. polymers. D. nucleotides. E. sodium and potassium ions. - Answer A. proteins. If a cell has the same concentration of dissolved molecules as its outside environment, the cell's condition is referred to as being A. isotonic. B. hypertonic. C. hypotonic. D. hydrophobic. E. hydrophilic. - Answer A. isotonic. type of transport of a solute across a membrane, up its concentration gradient, using protein carriers driven by the expenditure of chemical energy is known as A. osmosis. B. diffusion. C. facilitated transport.
The actual transport of protons by the proton pump is mediated by a transmembrane protein which undergoes a change in its A. conformation. B. amino acid sequence. C. net charge. D. solubility. E. immunity. - Answer A. conformation. The process often referred to as "cellular eating" is A. osmosis. B. pinocytosis. C. phagocytosis. D. diffusion. E. active transport. - Answer C. phagocytosis. Osmosis can only occur if water travels through the A. cell wall. B. semi-permeable membrane. C. vacuole. D. ER. E. cytoskeleton. - Answer B. semi-permeable membrane.
Organisms with a cell wall cannot carry out A. exocytosis. B. active transport. C. osmosis. D. diffusion. E. endocytosis. - Answer E. endocytosis.
The type of movement of molecules that is specific and passive, and which becomes saturated if all of the protein carriers are in use is A. exocytosis. B. facilitated diffusion. C. active transport. D. endocytosis. E. osmosis. - Answer B. facilitated diffusion.
The type of movement that is specific and requires carrier molecules and energy is A. exocytosis. B. facilitated diffusion. C. active transport. D. endocytosis. E. osmosis. - Answer C. active transport.
The accumulation of amino acids and sugars in animal cells can occur through A. ATP pumps. B. sodium-potassium pumps. C. glucose pumps. D. coupled transport. E. proton pumps. - Answer D. coupled transport.
A phospholipid molecule has a polar and a nonpolar end. Because of this, water molecules form A. polar bonds with the nonpolar end of the phospholipid molecule. B. polar bonds with the polar end of the phospholipid molecule. C. hydrogen bonds with the nonpolar end of the phospholipid molecule. D. hydrogen bonds with the polar end of the phospholipid molecule. E. covalent bonds with the nonpolar end of the phospholipid molecule. - Answer D. hydrogen bonds with
D. move from areas of high concentration to areas of lesser concentration until facilitated transport can assist the molecular equilibrium. E. move from areas of high concentration to areas of lesser concentration until an equilibrium is reached by active transport. - Answer A. move from areas of high concentration to areas of lesser concentration until an equilibrium is reached.
A research laboratory is attempting to collect the content of human red blood cells. The type of solution researchers should use to cause blood cell to lyse (burst) would be
A. hyperosmotic. B. isosmotic. C. hypoosmotic. D. osmotic. - Answer C. hypoosmotic.
A group of scientists perform an experiment in which they create an artificial cell with a selectively permeable membrane through which only water can pass. They inject a 5M solution of glucose into the cell and then place the cell into a beaker of water. After an hour, what effect do you expect to observe?
A. Water moves out of the cell B. Glucose moves out of the cell C. No net change in cell weight D. Water moves into the cell E. Glucose moves into the cell - Answer D. Water moves into the cell
A scientist performs an experiment in which they create an artificial cell with a selectively permeable membrane through which only water can pass. They inject a 5M solution of glucose into the cell and then place the cell into a beaker containing 10M glucose. What effect do you expect to observe?
A. Water moves out of the cell
B. Glucose moves out of the cell C. No net change in cell weight D. Water moves into the cell E. Glucose moves into the cell - Answer A. Water moves out of the cell
Membrane fluidity is affected by
A. temperature, cholesterol, types of fatty acids. B. size of molecules, polarity of molecules, temperature. C. types of fatty acids, waters affinity for hydrogen bonding. D. hyrophillic tails, hydrophobic heads, cholesterol. - Answer A. temperature, cholesterol, types of fatty acids.
Protein X contains four transmembrane domains, a short N-terminus and a long C-terminus. Following protein synthesis, the N-terminus of the protein faces the lumen (the inside) of the ER. After protein X is transported to the cell surface via exocytosis, you would expect the N-terminus of protein X to be
A. extracellular. B. cytoplasmic. C. in the lumen. D. in the lipid bilayer of the plasma membrane. - Answer A. extracellular.
Incubation of cells at 20C blocks the release of proteins from the trans-Golgi. Under such conditions, you would expect to see A. an increase in exocytosis. B. a decrease in exocytosis. C. an increase in endocytosis. D. a decrease in endocytosis. - Answer B. a decrease in exocytosis.
The rate of diffusion of molecules would be fastest in a cell with an
A. internal concentration of 45 percent and an external concentration of 50 percent in cold temperatures. B. internal concentration of 50 percent and an external concentration of 12 percent in cold temperatures. C. internal concentration of 50 percent and an external concentration of 12 percent in warm temperatures. D. internal concentration of 40 percent and an external concentration of 35 percent in warm temperatures. - Answer C. internal concentration of 50 percent and an external concentration of 12 percent in warm temperatures.
To test for the presence of starch, iodine can be used. A positive reaction results in a black color. A dialysis bag filled with starch solution and secured on both ends is placed in iodine solution. After 30 minutes the dialysis bag appears black. Based on this information, what most accurately describes what happened?
A. Due to its size and polarity, starch was able to exit the dialysis bag and interact with the iodine solution. B. Due to its size and polarity, iodine was able to enter the dialysis bag and interact with starch. C. Over time, both iodine and starch are equally distributed throughout the two solutions. - Answer B. Due to its size and polarity, iodine was able to enter the dialysis bag and interact with starch.
Matt is studying how the protein transferrin enters cells. He examines cells that have taken up transferrin, and finds clathrin-coated vesicles. What mechanism was used to take transferrin into the cell? A. Phagocytosis B. Pinocytosis C. Exocytosis D. Receptor-mediator endocytosis - Answer D. Receptor-mediator endocytosis
