Chapter 5 Study Guide Membrane Structure and Function

The newly discovered membrane channel protein that accounts for why water can cross a membrane more quickly than expected is: A. ATP synthetase B. Aquaporin C. The sodium-potassium pump D. Integrin

B. Aquaporin

http://www.flickr.com/photos/60296733@N06/5520405472/ A 10% glucose solution is placed in the thistle tube. The thistle tube is placed in a beaker that contains a 5% glucose solution. Where is the highest concentration of water found? A. In the 10% solution B. In the 5% solution C. The concentration of water is the same in both solutions. D. None of the above

B. In the 5% solution

A major chemical that regulates the fluidity of animal cell membranes by stiffening the membrane at higher temperatures and preventing the membrane from freezing at lower temperature is: A. cholesterol. B. lipid in nature. C. a steroid. D. All of the choices are correct.

D. All of the choices are correct.

Proteins in a membrane are: A. peripheral if they are on the inside surface held in place by the cytoskeleton. B. integral if they are embedded in the membrane and protrude from both surfaces of the bilayer C. integral if they protrude from only one surface of the bilayer. D. All of the choices are correct.

D. All of the choices are correct.

In speculating upon the origin of early cells and the cell membrane, which of the following statements is/are NOT plausible? A. Due to similarities in basic structure, the endoplasmic reticulum, Golgi body, vesicles, and other "cytomembranes" may have arisen as invaginations of the cell membrane. B. As long as a phospholipid-production mechanism is present, these molecules would naturally arrange themselves in two layers with the hydrophobic tails on the inside away from water. C. It would be nearly impossible to have a cell without a cell membrane. D. All of the choices are plausible. E. None of the choices are plausible.

D. All of the choices are plausible.

Which statement is true about the plasma membrane? A. The proteins make up the matrix of the membrane. B. The model can be likened to a sandwich where phospholipids are like the bread and proteins are like the filling. C. The fluid nature of the membrane is regulated by flip-flopping of the phospholipids from one side of the membrane to the other. D. Movement of proteins and phospholipids can occur sideways within the plane of the membrane.

D. Movement of proteins and phospholipids can occur sideways within the plane of the membrane.

If a living plant were moved from a freshwater aquarium to a saltwater aquarium, which of the following would occur? A. Nothing. The plant would be fine in either aquarium. B. The plant's cells would take on ions. C. The plant's cells would take on water and will lyse. D. The plant's cells would lose water and plasmolysis would occur.

D. The plant's cells would lose water and plasmolysis would occur.

Which of the following is the reason plants wilt on a hot summer day? A. to protect the leaves from full exposure to the sun B. an increase in turgor pressure C. heat weakens the plant cell walls D. loss of water resulting in a decrease in turgor pressure.

D. loss of water resulting in a decrease in turgor pressure.

Fluidity of a membrane increases as the percentage of unsaturated fatty acids in the phospholipids goes up. True False

True

In the sodium-potassium pump, sodium is transported out of the cell and potassium is transported into the cell as ATP is broken by a membrane protein. True False

True

Receptor-mediated endocytosis involves the use of specific proteins in the cell membrane. True False

True

The process by which a white blood cell or an amoeba engulfs bacteria is called phagocytosis. True False

True

Which of the following is true with respect to plant cell walls? A. They contain n-acetylglutamic acid. B. They all have secondary cell walls to some extent. C. There is a greater amount of cellulose in secondary cell walls than in primary cell walls. D. Lignin is found in primary cell walls of plants.

C. There is a greater amount of cellulose in secondary cell walls than in primary cell walls.

Red blood cells come in many "blood types" including type A, type B, type AB, type O [lacking proteins A and B], Rh positive, and Rh negative [lacking Rh+] and many others. If blood is transfused, the recipient detects any new or "foreign" proteins. These blood type proteins are A. in the plasma where they have been secreted by the red blood cells. B. inside the red blood cell cytoplasm. C. on the outer surface of the red blood cell membrane. D. evenly distributed throughout the cell contents and plasma. E. in the red blood cell nucleus.

C. on the outer surface of the red blood cell membrane.

http://www.flickr.com/photos/60296733@N06/5520405472/ A 10% glucose solution is placed in the thistle tube. The thistle tube is placed in a beaker that contains a 5% glucose solution. The solution in the thistle tube is _______ to the solution in the beaker. A. Hypertonic B. Hypotonic C. Isotonic D. None of the above

A. Hypertonic

The current theory of the structure of the plasma membrane is best described by the ____ model. A. sandwich B. fluid-mosaic C. unit membrane D. electrochemical E. unipermeable

B. fluid-mosaic

Which of the following is NOT associated with animal cells? A. an extracellular matrix B. plasmodesmata C. gap junctions D. adhesion junctions (desmosomes) E. tight junctions

B. plasmodesmata

Which statement is NOT true about the proteins in the plasma membrane? A. Proteins may be attached to the inner surface of the plasma membrane. B. The hydrophobic portion of a protein is embedded within the membrane. C. Some peripheral proteins are connected to cytoskeletal filaments. D. Integral proteins are responsible for membrane functions. E. Glycoproteins contain carbohydrate chains that are oriented toward the inner surface of the membrane.

E. Glycoproteins contain carbohydrate chains that are oriented toward the inner surface of the membrane.

Having similar ____________ would allow tissues and organs to be transplanted easily. A. cell recognition proteins B. major histocompatibility complex proteins C. carbohydrate chains in the cell membrane D. all of the choices are involved in tissue transplantation

D. all of the choices are involved in tissue transplantation

The process by which cholesterol is transported into the cell by binding of LDL to its receptor and the internalization of the receptor-LDL complex is A. facilitated transport. B. active transport. C. cotransport. D. endocytosis. E. exocytosis.

D. endocytosis.

http://www.flickr.com/photos/60296733@N06/5520405506/ Study the series of pictures at right to identify the process as: A. facilitated transport B. active transport C. passive transport D. osmosis

A. facilitated transport

Sugars and amino acids are carried into the cell by means of A. facilitated transport. B. diffusion C. endocytosis. D. exocytosis.

A. facilitated transport.

Active transport A. requires an input of ATP. B. is involved in diffusion. C. occurs in osmosis and facilitated transport. D. All of the choices are correct.

A. requires an input of ATP.

Which is the best definition of osmosis? A. The movement of molecules from an area of their higher concentration to an area of their lower concentration. B. The movement of water across a semi permeable membrane from an area of higher water concentration to an area of lower water concentration. C. The movement of molecules from an area of their lower concentration to an area of their higher concentration. D. The movement of water across a semi permeable membrane from an area of lower water concentration to an area of higher water concentration. E. The movement of a substance against its concentration gradient through the release of energy from ATP.

B. The movement of water across a semi permeable membrane from an area of higher water concentration to an area of lower water concentration.

If a cell is placed in a hypotonic solution, which will occur? A. Salts will move into the cell from the surrounding solution. B. Water will move into the cell from the surrounding solution. C. Salts will move out of the cell into the surrounding solution. D. Water will move out of the cell into the surrounding solution. E. None of the choices will occur.

B. Water will move into the cell from the surrounding solution.

All life forms currently have a basic cell membrane so we presume that the earliest forms of life had this "fence" isolating the internal organization from the external chaos. It is likely that the primordial environment was acidic. In such a case, the cell membrane would have to include A. a sodium (Na+) pump. B. a proton (H+) pump. C. mitochondria underneath in order to provide energy for active transport. D. an acid-proof cell wall. E. a totally nonpermeable membrane.

B. a proton (H+) pump.

Plants show turgor pressure when A. cells are losing water from their water vacuoles. B. cells contain water vacuoles that are full of water. C. water is being used up in photosynthesis. D. water is being evaporated from the leaves.

B. cells contain water vacuoles that are full of water.

Which phrase does NOT describe one of the functions of proteins of the plasma membrane? A. forming a channel through the membrane B. initiating the replication of the genetic material C. binding to a substance to carry it through the membrane D. acting as a receptor for substances external to the cell E. increasing the rate of a chemical reaction

B. initiating the replication of the genetic material

Which of the following protein functions is not correctly associated with its correct integral protein? A. carrier proteins-facilitate passage of molecules through the membrane B. enzymatic proteins-catalyze a specific reaction C. channel proteins-block the activity of carrier proteins D. cell recognition proteins-recognize pathogens

C. channel proteins-block the activity of carrier proteins

In a cell where there is no net movement of water, the amount leaving the cell and entering the cell is the same. In what type of environment is this cell found? A. hypertonic B. hypotonic C. isotonic D. none of the above

C. isotonic

http://www.flickr.com/photos/60296733@N06/5520405472/ A 10% glucose solution is placed in the thistle tube. The thistle tube is placed in a beaker that contains a 5% glucose solution. There is a differentially permeable membrane across the broad end of the tube, which is permeable to water but not to the sugar glucose. As diffusion occurs: A. the 10% solution will become more concentrated and the 5% solution will become less concentrated B. both solutions will become more concentrated. C. the 10% solution will become less concentrated and the 5% solution will become more concentrated. D. both solutions will become less concentrated.

C. the 10% solution will become less concentrated and the 5% solution will become more concentrated.

Eukaryotic cells are substantially larger than bacterial cells and average over 20 times more volume-per-surface-area than bacterial cells. How can the eukaryotic cell membrane provide this higher rate of exchange of materials? A. Plasma membrane folds increase the surface area. B. Carrier proteins speed the rate at which a solute crosses the plasma membrane in the direction of decreasing concentration. C. Mitochondria are concentrated near membranes to provide energy for active transport of molecules or ions. D. Large molecules are engulfed by vesicle formation. E. All of the choices are correct.

E. All of the choices are correct.

Whether a molecule can cross the plasma membrane depends upon A. the size of the molecule. B. the shape of the molecule. C. the chemical properties of the molecule. D. the charge of the molecule. E. All of the choices are correct.

E. All of the choices are correct.

Some parasites and disease agents regularly change their identity before our immune system can build up substantial antibodies. How could cells change their chemical identity on a regular basis? A. Rapid evolution produces mutations. B. A new phospholipid bilayer is generated to replace the old layer. C. Because the membrane is "set," the cell must reproduce and then the cell with the old membrane must die. D. Cells eliminate all surface proteins and present only a naked lipid bilayer. E. Different glycolipids and glycoproteins are produced internally and moved into the plasma membrane.

E. Different glycolipids and glycoproteins are produced internally and moved into the plasma membrane.

Freshwater protozoans react to a/an _____ environment by removing water through _____. A. hypertonic, turgor pressure B. hypotonic, turgor pressure C. isotonic, a contractile vacuole D. hypertonic, a contractile vacuole E. hypotonic, a contractile vacuole

E. hypotonic, a contractile vacuole

Which is the best definition of active transport? A. movement of molecules from an area of their higher concentration to an area of their lower concentration B. movement of water across a semi permeable membrane from an area of higher water concentration to an area of lower water concentration C. movement of molecules from an area of their lower concentration to an area of their higher concentration D. movement of water across a semi permeable membrane from an area of lower water concentration to an area of higher water concentration E. movement of a substance against its concentration through the release of energy from ATP

E. movement of a substance against its concentration through the release of energy from ATP

In a phospholipid bilayer, the A. phosphate groups are hydrophobic. B. fatty acid tails are ionized. C. fatty acid tails are hydrophilic. D. proteins are located only between the two layers. E. phosphate heads are oriented toward the exterior of the cell or toward the cytoplasm.

E. phosphate heads are oriented toward the exterior of the cell or toward the cytoplasm.

The major functions of the plasma membrane do NOT include A. separation of the fluid environments inside and outside the cell. B. regulation of molecules and ions that pass into and out of the cell. C. recognition and communication between different cells and tissues. D. maintaining connections between adjacent cells. E. production of proteins used in construction of the cell wall.

E. production of proteins used in construction of the cell wall.

In the cells that line the lumen of the small intestine, gap junctions keep materials from the digestive tract from slipping between the cells and entering the tissues. True False

False

An extracellular matrix helps some cells to adhere to neighboring cells. True False

True