Bio1107 Exam 2 Possible Questions

In biological membranes the lipid bilayer contains phospholipids, each with a head and two fatty acid tails. They are arranged so that the A. nonpolar tails extend into the extracellular fluid. B. fatty acids face the interior of the cell. C. nonpolar tails extend into the cytoplasm. D. fatty acid tails point toward each other. E. fatty acid heads are oriented head-to-head.

D. fatty acid tails point toward each other.

The cell membrane A. regulates movement of substances within the cytoplasm. B. maintains genetic information within the cell. C. determines onset of cell division. D. helps maintain the internal environment of the cell. E. provides useful energy for the cell.

D. helps maintain the internal environment of the cell.

Chloroplasts are a kind of A. endoplasmic reticulum. B. contractile vacuole. C. peroxisome. D. plastid. E. Golgi apparatus.

D. plastid.

A function of the nucleolus is to A. replicate DNA during cell division. B. carry out transcription of DNA. C. regulate molecular entry into and exit from the nucleus. D. provide a space for ribosome assembly. E. assemble proteins.

D. provide a space for ribosome assembly.

Plants depend on their cell walls to limit the amount of water entering their cells and maintain _______, which helps keep plants upright. A. osmosis B. aquaporins C. turgor pressure D. equilibrium E. simple diffusion

C. turgor pressure

_______ proteins are embedded in biological membranes, whereas _______ proteins are associated with surface regions of biological membranes. A. Integral; peripheral B. Extracellular; peripheral C. Transmembrane; integral D. Peripheral; extracellular E, Cytoskeletal; integral

A. Integral; peripheral

Which is a correct pairing of a substance and the process by which it is transported across cell membranes? A. Pancreatic digestive enzymes by exocytosis B. A solution by receptor-mediated endocytosis C. Water by secondary active transport D. Cholesterol by pinocytosis E. Glucose by phagocytosis

A. Pancreatic digestive enzymes by exocytosis

Which statement about diffusion is false? A. Simple diffusion depends on specific carrier or channel proteins. B. Diffusion occurs as the result of the random movement of molecules. C. Molecules move from areas of greater concentration to areas of lesser concentration. D. The rate of transport depends on the concentration of the molecule transported. E. Facilitated diffusion does not require ATP.

A. Simple diffusion depends on specific carrier or channel proteins.

Lactose is transported via secondary active transport into bacterial cells. Which of the following would be absent from a diagram illustrating the mechanism of this transport system? A. The direct use of ATP to transport lactose B. The movement of lactose against its concentration gradient C. Diffusion of a substance in the same direction as its concentration gradient D. Coupling of lactose transport to transport of another substance E. The formation of a concentration gradient

A. The direct use of ATP to transport lactose

A unicellular organism adapted to living in salt water is placed in a freshwater tank. What is the likely outcome? A. Water moves into the cell, causing it to burst. B. Water and salt move in opposite directions until the organism can adapt. C. Water moves out of the cell until the organism can adapt. D. Water moves out of the cell, causing it to shrivel. E. Water moves into the cell until the organism can adapt.

A. Water moves into the cell, causing it to burst.

There are two basic types of active transport. A main difference between them is that only one uses A. a concentration gradient established by a previous reaction to drive transport. B. integral membrane proteins for transport of substances across the membrane. C. diffusion to move the ions across the membrane. D. energy expenditure to move a substance from lower to higher concentration across a membrane. E. hydrolysis of ATP as an energy source.

A. a concentration gradient established by a previous reaction to drive transport.

The main components of biological membranes are A. lipids, proteins, and carbohydrates. B. monosaccharides and polysaccharides. C. nucleotides and nucleosides. D. cholesterol and polar water molecules. E. enzymes, electron acceptors, and electron donors.

A. lipids, proteins, and carbohydrates.

Cells secrete materials to the exterior environment through the process of A. phagocytosis. B. exocytosis. C. endocytosis. D. receptor-mediated endocytosis. E. pinocytosis.

B. exocytosis.

Osmosis, the movement of water though specialized membrane channels, is an example of: A. movement of water by carrier proteins. B. facilitated diffusion. C. secondary active transport. D. active transport. E. simple diffusion.

B. facilitated diffusion.

Protein movement within a membrane may be restricted by A. oligosaccharides. B. interactions with cytoskeletal proteins on the membrane's inner face. C. closure of gated channel oligosaccharides. D. glycolipids and glycoproteins. E. hydrophilic regions within the membrane.

B. interactions with cytoskeletal proteins on the membrane's inner face.

A structure is considered extracellular if it A. contains lipids. B. lies outside the cell membrane. C. is rigid. D. contains peptidoglycans. E. is impermeable to most substances.

B. lies outside the cell membrane.

Osmosis is A. the unidirectional diffusion of water across membranes. B. the movement of water across selectively permeable membranes. C. a process that is unaffected by solute concentrations inside cells. D. a process that requires energy. E. the active transport of water across membranes.

B. the movement of water across selectively permeable membranes.

A species of fish that lives in the ocean has cells with a lower solute concentration than the surrounding ocean waters. To maintain cell homeostasis under these conditions, these fish A. use simple diffusion. B. use active transport. C. produce large volumes of urine. D. take in large quantities of salt. E. use facilitated diffusion.

B. use active transport.

Some white blood cells can defend the body against invaders through A. exocytosis. B. receptor-mediated endocytosis. C. phagocytosis. D. pinocytosis. E. active transport.

C. phagocytosis.

All the following may be involved in facilitated diffusion except A. carrier proteins. B. channel proteins. C. ATP, which is used as an energy source. D. ligands. E. gated channels.

C. ATP, which is used as an energy source.

Which is a function of the proteins lining the extracellular surfaces of coated pits involved in receptor-mediated endocytosis? A. signaling to a newly formed vesicle where to go B. Targeting the coated vesicle to the lysosome C. Forming the receptors that bind a specific molecule D. Providing stability for the vesicle E. Fusing with a lysosome

C. Forming the receptors that bind a specific molecule

What does the nucleoid region of a prokaryotic cell contain? A. Enzymes that carry out metabolic reactions B. Proteins that regulate movement of molecules within the cell C. The hereditary material that directs cell functions D. Phospholipids that are organized into a membrane E. Ribosomes that synthesize cell proteins

C. The hereditary material that directs cell functions

If a cell is bathed in an extracellular solution high in calcium ions, it would use _______ to maintain a normal, low intracellular concentration of calcium ions. A. secondary active transport for passive diffusion of Ca2+ B. diffusion as the primary means of Ca2+ transport C. active transport against the concentration gradient of Ca2+ D. carrier proteins to increase the rate of diffusion E. calcium ion channels for facilitated diffusion

C. active transport against the concentration gradient of Ca2+

Movement of materials among plant cells is made possible by A. the semirigid cell wall. B. an internal cytoskeleton. C. channels called plasmodesmata. D. motor proteins such as kinesin. E. constantly beating cilia.

C. channels called plasmodesmata.

If you wanted to stop the movement of a ciliated protist in culture, you could incubate it in a substance that inhibits A. actin. B. myosin. C. dynein. D. flagellin. E. kinesin.

C. dynein.

Which is a molecule found in plant extracellular matrices but not in animal cell extracellular matrices? A. Proteoglycans B. Collagen C. Polysaccharides D. Cellulose E. Integrin

D. Cellulose

Which experimental design can be expected to produce evidence that a membrane's fluidity is affected by temperature? A. Compare the nucleotide sequences of the gene encoding the same receptor protein present in neuronal cell membranes from a desert mouse, an Arctic rabbit, and a tropical monkey. B. Collect fish of the same species from Lake Michigan in both winter and summer, and analyze differences in membrane protein composition of liver cells. C. Isolate and analyze the fatty acids present in intestinal cell membranes from three fish species from the Mediterranean Sea. D. Compare the rate of intermixing of sheep and goat membrane proteins after fusing sheep and goat liver cells in a cold room and in a warmed incubator. E. Hold fish of the same species at different environmental temperatures in a lab, then isolate their liver cells and analyze differences in their membrane proteins.

D. Compare the rate of intermixing of sheep and goat membrane proteins after fusing sheep and goat liver cells in a cold room and in a warmed incubator.

What key feature distinguishes eukaryotes from prokaryotes? A. Use of nucleic acids for storing biological information B. Ribosomal synthesis of cellular proteins C. Ability to convert light energy to chemical energy D. Separation of cell functions into membrane-bound compartments E. Ability to eliminate waste materials

D. Separation of cell functions into membrane-bound compartments

Which occurs during both endocytosis and exocytosis? A. Materials are released into the cytoplasm. B. Membrane receptors bind to specific ligands. C. Vesicles fuse with the cell membrane. D. The cell membrane undergoes compositional change. E. Vesicles fuse with lysosomes.

D. The cell membrane undergoes compositional change.

Lysosomes are important to eukaryotic cells because they contain A. their own DNA molecules. B. photosynthetic pigments. C. starch molecules for energy storage. D. digestive enzymes. E. cell waste materials.

D. digestive enzymes.

Many animal cells are surrounded by a(n) A. cell wall. B. extracellular wall. C. cell matrix. D. extracellular matrix. E. extracellular gel.

D. extracellular matrix.

Temperature affects the fluidity of plasma membranes. Some organisms maintain their membrane fluidity when it is extremely cold by A. closing protein channels. B. increasing the number of transmembrane protein channels. C. increasing the number of cholesterol molecules present. D. replacing saturated fatty acids with unsaturated fatty acids. E. using fatty acids with longer tails.

D. replacing saturated fatty acids with unsaturated fatty acids.

Five statements about cell membranes are given. Which statement can be used to explain the importance of the cell membrane to cell survival? A. The cell membranes of prokaryotes and eukaryotes have the same basic structure. B. The cell membrane is so small that it is best viewed with an electron microscope. C. Cell membranes are composed of a phospholipid bilayer embedded with proteins. D. The cell membrane expands or shrinks by the addition or removal of phospholipid molecules. E. Cell membranes are selectively permeable with respect to molecules and ions.

E. Cell membranes are selectively permeable with respect to molecules and ions.

Which statement about diffusion is false? A. When concentrations of diffusing molecules are in equilibrium, net diffusion stops, though molecules continue moving. B. Movement of molecules during diffusion is random. C. During diffusion, molecules move from areas of greater concentration to areas of lesser concentration. D. The rate of simple diffusion can be changed. E. During diffusion, the cell membrane becomes increasingly less permeable to the diffusing substance.

E. During diffusion, the cell membrane becomes increasingly less permeable to the diffusing substance.

Which molecule will diffuse across a phospholipid bilayer fastest when there are no proteins associated with the bilayer? A. Na+ B. CH3COO- C. H2O D. NH4+ E. NH3

E. NH3

Which statement correctly states how cell size affects the ability of the cell to take in and use nutrients from its environment? A. The larger the cell, the larger its surface area-to-volume ratio, which decreases the rate of transport of nutrients into all parts of the cell. B. The smaller the cell, the smaller its surface area-to-volume ratio, which decreases the rate of transport of nutrients into all parts of the cell. C. The larger the cell, the smaller its surface area-to-volume ratio, which increases the rate of transport of nutrients into all parts of the cell. D. A cells ability to take in and use nutrients remains constant regardless of its size. E. The smaller the cell, the larger its surface area-to-volume ratio, which increases the rate of transport of nutrients into all parts of the cell.

E. The smaller the cell, the larger its surface area-to-volume ratio, which increases the rate of transport of nutrients into all parts of the cell.

If an animal cell needs to acquire more of a particular amino acid for a physiological process, it can employ _______ when the amino acid is more concentrated inside the cell than in the extracellular fluid. A. synthesis B. simple diffusion C. facilitated diffusion D. osmosis E. active transport

E. active transport

Cell-to-cell adhesion often occurs through the interactions of A. organelles. B. receptors. C. lipids. D. cytoskeletons. E. carbohydrates.

E. carbohydrates.

Persons with the inherited disease familial hypercholesterolemia have very high levels of cholesterol in their blood because of A. an inability to produce cholesterol. B. an inability of the liver to release cholesterol into the blood. C. deficient lysosomes in the liver. D. defective clathrin-coated vesicles. E. deficient receptor-mediated endocytosis of LDLs in the liver.

E. deficient receptor-mediated endocytosis of LDLs in the liver.

All the following affect the rate of diffusion of a substance except A. the temperature of the solution. B. the concentration gradient of the molecule. C. the size of diffusing molecules. D. the diameter of diffusing molecules. E. the presence of other solutes in the solution.

E. the presence of other solutes in the solution.