Campbell Biology in Focus 3rd Edition

1. Home 2. Practice Test 3. Chapter 5 Practice Test Chapter 5: Membrane Transport and Cell Signaling Question1 Question 1:Which cell structure allows selective permeability between a cell and its external environment? (Section 5.1) SHOW HINT mitochondria the plasma membrane chloroplasts endoplasmic reticulum lysosomes right answer feedback:The plasma membrane allows some substances to cross into a cell more easily than others. Question2 Question 2:Which statement about the role of phospholipids in the structure and function of biological membranes is correct? (Section 5.1) SHOW HINT They are triacylglycerols, which are commonly available in foods. Phospholipids form a single sheet in water. Phospholipids form a structure in which the hydrophobic portion faces outward. Phospholipids are completely insoluble in water. Phospholipids form a selectively permeable structure. right answer feedback:Their structure allows some substances to penetrate easily and blocks others. Question3 Question 3:Which statement about the fluid mosaic model is true? (Section 5.1) SHOW HINT The mosaic aspect of the membrane is due to the glycosylation of inner leaflet phospholipids. Only phospholipids are capable of moving in the membrane. The fluid aspect of the membrane is due to the behavior of phospholipids, and the mosaic aspect is due to the presence of carbohydrates. The fluid aspect of the membrane is due to the lateral and rotational movement of phospholipids, and embedded proteins account for the mosaic aspect. The fluid aspect of the membrane describes its structure at normal temperatures, and the mosaic aspect describes the behavior of the membrane as the temperature is lowered. right answer feedback:This is what the term fluid mosaic refers to. Question4 Question 4:Under the fluid mosaic model, where in the plasma membrane would cholesterol most likely be found? (Section 5.1) SHOW HINT on the outside (external) surface of the membrane in the interior and on the inside surface, but not on the outside surface on either surface of the membrane, but not in the interior of the membrane on the inside (cytoplasmic) surface wedged between phospholipid molecules in the interior of the membrane right answer feedback:The steroid cholesterol, wedged between phospholipid molecules in the plasma membranes of animals, helps stabilize the membrane. Question5 Question 5:Which functional process is not a consequence of the association of proteins with biological membranes? (Section 5.1) SHOW HINT cell-cell communication intercellular joining cell-cell recognition enzymatic activity energy, carbon, and nitrogen storage right answer feedback:Proteins are not present in biological membranes to act as stores of energy, carbon, and nitrogen. Question6 Question 6:Which statement is correct concerning carbohydrates associated with the plasma membrane? (Section 5.1) SHOW HINT Carbohydrates associated with the plasma membrane are located on both surfaces of the membrane. Carbohydrates are only found associated with the membranes of prokaryotic cells. Carbohydrates on the plasma membrane are typically short chains of between two and five monosaccharides. Membrane carbohydrates function primarily in cell-cell recognition. The carbohydrate composition of most eukaryotic plasma membranes is quite similar. Question7 Question 7:Where in the fluid mosaic model of the membrane would carbohydrates be found? (Section 5.1) SHOW HINT on both hydrophilic surfaces of the membrane, but not in the hydrophobic interior Carbohydrates are rarely associated with plasma membranes. in the interior of the membrane on the inside (cytoplasmic) surface of the membrane on the outside (external) surface of the membrane right answer feedback:Membrane carbohydrates are covalently bonded to lipids or proteins and extend out from the external side of the plasma membrane as a means of cell identification