AP Bio Ch. 5-7 Test
For this pair of items, choose the option that best describes their relationship. (A) The probability that amino acids with nonpolar side chains are hydrophobic. (B) The probability that amino acids with side chains containing a carboxyl group are hydrophobic. A) Item (A) is greater than item (B). B) Item (A) is less than item (B). C) Item (A) is exactly or very approximately equal to item (B). D) Item (A) may stand in more than one of the above relations to item (B)
A
In most cells, there are electrochemical gradients of many ions across the plasma membrane even though there are usually only one ortwo electrogenic pumps present in the membrane. The gradients of the otherions are most likely accounted for by A) cotransport proteins. B) ion channels. C) carrier proteins. D) B and C only E) A, B, and C
A
Large organic molecules are usually assembled by polymerization of a few kinds of simple subunits. Which of the following is an exception to this statement? A) a steroid B) cellulose C) DNA D) an enzyme E) a contractile protein
A
ONE STOP SIGN If 2 molecules of the general type shown in Figure 5.1 were linked together, carbon 1 of one molecule to carbon 4 of the other, the single molecule that would result would be A) maltose. B) fructose. C) glucose. D) galactose. E) sucrose.
A
Of the following, which cell structure would most likely be visible with a light microscope that has been manufactured to the maximum resolving power possible? A) mitochondrion B) microtubule C) ribosome D) largest microfilament E) nuclear pore
A
) Why are human sex hormones considered to be lipids? A) They are essential components of cell membranes. B) They are steroids, which are not soluble in water. C) They are made of fatty acids. D) They are hydrophilic compounds. E) They contribute to atherosclerosis.
B
Recent evidence shows that the extracellular matrix can take part in regulating the expression of genes. A likely possibility forthis might be which of the following? A) Mechanical signals of the ECM can alterthe cytoskeleton, which can alterintracellular signaling. B) Intracellular signals might cause changes in the fibronectin binding to the cell surface. C) Orientation of microfilaments to the ECM can change the gene activity. D) Fibronectin binds to integrins built into the plasma membrane. E) Proteoglycans in the ECM become large enough in aggregate to force genetic alteration
A
Roger Kornberg used this method for elucidating the structure ofRNA polymerase. A) X-ray crystallography B) bioinformatics C) analysis of amino acid sequence of smallfragments D) NMRspectroscopy E) high-speed centrifugation
A
The bonding of two amino acid molecules to form a larger molecule requires A) the release of a water molecule. B) the release of a carbon dioxide molecule. C) the addition of a nitrogen atom. D) the addition of a water molecule. E) both B and C
A
The bonding of two amino acid molecules to form a larger molecule requires which of the following? A) removal of a water molecule B) addition of a water molecule C) formation of an ionic bond D) formation of a hydrogen bond E) both A and C
A
The difference between pinocytosis and receptor-mediated endocytosis is that A) pinocytosis brings only waterinto the cell, butreceptor-mediated endocytosis brings in other molecules as well. B) pinocytosis increases the surface area of the plasma membrane whereas receptor-mediated endocytosis decreases the plasma membrane surface area. C) pinocytosis is nonselective in the molecules it brings into the cell, whereas receptor-mediated endocytosis offers more selectivity. D) pinocytosis requires cellular energy, butreceptor-mediated endocytosis does not. E) pinocytosis can concentrate substances from the extracellularfluid, but receptor-mediated endocytosis cannot.
A
The enzyme amylase can break glycosidic linkages between glucose monomers only if the monomers are the α form.Which of the following could amylase break down? A) glycogen B) cellulose C) chitin D) A and B only E) A, B, and C
A
The fact that the outer membrane of the nuclear envelope has bound ribosomes allows one to most reliably conclude that A) at least some of the proteins that function in the nuclear envelope are made by the ribosomes on the nuclear envelope. B) the nuclear envelope is not part of the endomembrane system. C) the nuclear envelope is physically continuous with the endoplasmic reticulum. D) small vesicles from the Golgi fuse with the nuclear envelope. E) nuclear pore complexes contain proteins.
A
The mitochondrion, like the nucleus, has two or more membrane layers. How is the innermost of these layers different from that of the nucleus? A) The inner mitochondrial membrane is highly folded. B) The two membranes are biochemically very different. C) The space between the two layers of the nuclear membrane is larger. D) The inner membrane of the mitochondrion is separated out into thylakoids. E) The inner mitochondrial membrane is devoid of nearly all proteins.
A
The presence of cholesterol in the plasma membranes of some animals A) enables the membrane to stay fluid more easily when cell temperature drops. B) enables the animal to remove hydrogen atoms from saturated phospholipids. C) enables the animal to add hydrogen atoms to unsaturated phospholipids. D) makes the membrane less flexible, allowing it to sustain greater pressure from within the cell. E) makes the animal more susceptible to circulatory disorders.
A
The sodium-potassium pump in animal cells requires cytoplasmic ATP to pump ions across the plasma membrane.When the proteins of the pump are first synthesized in the rough ER, what side of the ER membrane will the ATP binding site be on? A) It will be on the cytoplasmic side of the ER. B) It will be on the side facing the interior of the ER. C) It could be facing in either direction because the orientation of proteins is scrambled in the Golgi apparatus. D) It doesnʹt matter, because the pump is not active in the ER.
A
Which bonds are created during the formation of the primary structure of a protein? A) peptide bonds B) hydrogen bonds C) disulfide bonds D) phosphodiester bonds E) A, B, and C
A
Which of the following are capable of converting light energy to chemical energy? A) chloroplasts B) mitochondria C) leucoplasts D) peroxisomes E) Golgi bodies
A
Which of the following bestdescribes the flow of information in eukaryotic cells? A) DNA→ RNA→ proteins B) RNA → proteins → DNA C) proteins → DNA → RNA D) RNA → DNA → proteins E) DNA→ proteins → RNA
A
Which of the following contains hydrolytic enzymes? A) lysosome B) vacuole C) mitochondrion D) Golgi apparatus E) peroxisome
A
Which of the following is a reasonable explanation for why unsaturated fatty acids help keep any membrane more fluid at lower temperatures? A) The double bonds form kinks in the fatty acid tails, forcing adjacent lipids to be further apart. B) Unsaturated fatty acids have a higher cholesterol content and therefore more cholesterol in membranes. C) Unsaturated fatty acids permit more water in the interior of the membrane. D) The double bonds block interaction among the hydrophilic head groups of the lipids. E) The double bonds result in shorter fatty acid tails and thinner membranes.
A
Which of the following is not a polymer? A) glucose B) starch C) cellulose D) chitin E) DNA
A
Which of the following is one of the ways that the membranes of winter wheat are able to remain fluid when it is extremely cold? A) by increasing the percentage of unsaturated phospholipids in the membrane B) by increasing the percentage of cholesterol molecules in the membrane C) by decreasing the number of hydrophobic proteins in the membrane D) by co-transport of glucose and hydrogen E) by using active transport
A
Which of the following is true of both starch and cellulose? A) They are both polymers of glucose. B) They are geometric isomers of each other. C) They can both be digested by humans. D) They are both used for energy storage in plants. E) They are both structural components of the plant cell wall.
A
Which of the following possesses a microtubular structure similarto a basal body? A) centriole B) lysosome C) nucleolus D) peroxisome E) ribosome
A
Which of the following span the phospholipids bilayer, usually a number of times? A) transmembrane proteins B) integral proteins C) peripheral proteins D) integrins E) glycoproteins
A
Which of the following statements is false for the class of biological molecules known as lipids? A) They are soluble in water. B) They are an important constituent of cell membranes. C) They contain more energy than proteins and carbohydrates. D) They are not true polymers. E) They contain waxes and steroids.
A
Which of the following would likely move through the lipid bilayer of a plasma membrane mostrapidly? A) CO2 B) an amino acid C) glucose D) K+ E) starch
A
Which structure is the site of the synthesis of proteins that may be exported from the cell? A) rough ER B) lysosomes C) plasmodesmata D) Golgi vesicles E) tight junctions
A
Who proposed that membranes are a phospholipid bilayer between two layers of hydrophilic proteins? A) H. Davson and J. Danielli B) I. Langmuir C) C. Overton D) S. Singer and G. Nicolson E) E. Gorter and F. Grendel
A
According to the fluid mosaic model of cell membranes, which of the following is a true statement about membrane phospholipids? A) They can move laterally along the plane of the membrane. B) They frequently flip-flop from one side of the membrane to the other. C) They occur in an uninterrupted bilayer, with membrane proteins restricted to the surface of the membrane. D) They are free to depart from the membrane and dissolve in the surrounding solution. E) They have hydrophilic tails in the interior of the membrane.
A
All of the following are polysaccharides except A) glycogen B) starch C) chitin D) cellulose E) amylopectin
A
Cells can be described as having a cytoskeleton of internal structures that contribute to the shape, organization, and movement of the cell.Which of the following are part of the cytoskeleton? A) the nuclear envelope B) mitochondria C) microfilaments D) lysosomes E) nucleoli
A
Familial hypercholesterolemia is characterized by which of the following? A) defective LDL receptors on the cell membranes B) poor attachment of the cholesterol to the extracellular matrix of cells C) a poorly formed lipid bilayerthat cannot incorporate cholesterol into cell membranes D) inhibition of the cholesterol active transport system in red blood cells E) a general lack of glycolipids in the blood cell membranes
A
For this pair of items, choose the option that best describes their relationship. (A) The number of purines in the DNA strand 5ʹ-AAGAGGAGAAA-3ʹ (B) The number of pyrimidines in the DNA strand 5ʹ-AAGAGGAGAAA-3ʹ A) Item (A) is greater than item (B). B) Item (A) is less than item (B). C) Item (A) is exactly or very approximately equal to item (B). D) Item (A) may stand in more than one of the above relations to item (B).
A
A double-stranded DNA molecule contains a total of 120 purines and 120 pyrimidines. This DNA molecule could be composed of A) 120 adenine and 120 uracil molecules. B) 120 thymine and 120 adenine molecules. C) 120 cytosine and 120 thymine molecules. D) 240 adenine and 240 cytosine molecules. E) 240 guanine and 240 thymine molecules.A double-stranded DNA molecule contains a total of 120 purines and 120 pyrimidines. This DNA molecule could be composed of A) 120 adenine and 120 uracil molecules. B) 120 thymine and 120 adenine molecules. C) 120 cytosine and 120 thymine molecules. D) 240 adenine and 240 cytosine molecules. E) 240 guanine and 240 thymine molecules.
B
A molecule with the formula C18H36O2 is probably a A) carbohydrate. B) fatty acid. C) protein. D) nucleic acid. E) hydrocarbon
B
A new organism is discovered in the forests of Costa Rica. Scientists there determine that the polypeptide sequence of hemoglobin from the new organism has 72 amino acid differences from humans, 65 differences from a gibbon, 49 differences from a rat, and 5 differences from a frog. These data suggest that the new organism A) is more closely related to humans than to frogs. B) is more closely related to frogs than to humans. C) may have evolved from gibbons but not rats. D) is more closely related to humans than to rats. E) may have evolved from rats but not from humans and gibbons.
B
All of the following contain amino acids except A) hemoglobin. B) cholesterol. C) antibodies. D) enzymes. E) insulin
B
All of the following statements concerning saturated fats are true except A) They are more common in animals than in plants. B) They have multiple double bonds in the carbon chains of their fatty acids. C) They generally solidify at room temperature. D) They contain more hydrogen than saturated fats having the same number of carbon atoms. E) They are one of several factors that contribute to atherosclerosis.
B
An animal cell lacking oligosaccharides on the external surface of its plasma membrane would likely be impaired in which function? A) transporting ions against an electrochemical gradient B) cell-cellrecognition C) maintaining fluidity of the phospholipid bilayer D) attaching to the cytoskeleton E) establishing the diffusion barrierto charged molecules
B
DNAase is an enzyme that catalyzes the hydrolysis of the covalent bonds that join nucleotides together. What would first happen to DNA molecules treated with DNAase? A) The two strands of the double helix would separate. B) The phosphodiester bonds between deoxyribose sugars would be broken. C) The purines would be separated from the deoxyribose sugars. D) The pyrimidines would be separated from the deoxyribose sugars. E) All bases would be separated from the deoxyribose sugars.
B
For this pair of items, choose the option that best describes their relationship. (A) The number of alpha glucose 1-4 linkages in cellulose (B) The number of alpha glucose 1-4 linkages in starch A) Item (A) is greater than item (B). B) Item (A) is less than item (B). C) Item (A) is exactly or very approximately equal to item (B). D) Item (A) may stand in more than one of the above relations to item (B)
B
For this pair of items, choose the option that best describes their relationship. (A) The number of cis double bonds in saturated fatty acids (B) The number of cis double bonds in unsaturated fatty acids A) Item (A) is greaterthan item (B). B) Item (A) is lessthan item (B). C) Item (A) is exactly or very approximately equal to item (B). D) Item (A) may stand in more than one of the above relations to item (B).
B
Grana, thylakoids, and stroma are all components found in A) vacuoles. B) chloroplasts. C) mitochondria. D) lysosomes. E) nuclei.
B
If one strand of a DNA molecule has the sequence of bases 5ʹATTGCA3ʹ, the other complementary strand would have the sequence A) 5ʹTAACGT3ʹ. B) 3ʹTAACGT5ʹ. C) 5ʹUAACGU3ʹ. D) 3ʹUAACGU5ʹ. E) 5ʹUGCAAU3ʹ.
B
In animal cells, hydrolytic enzymes are packaged to prevent general destruction of cellular components.Which of the following organelles functions in this compartmentalization? A) chloroplast B) lysosome C) central vacuole D) peroxisome E) glyoxysome
B
In the fractionation of homogenized cells using centrifugation, the primary factor that determines whether a specific cellular component ends up in the supernatant or the pellet is A) the relative solubility of the component. B) the size and weight of the component. C) the percentage of carbohydrates in the component. D) the number of enzymes in the fraction. E) the presence or absence of lipids in the component.
B
In which of the following would there be the greatest need for osmo regulation? A) an animal connective tissue cell bathed in isotonic body fluid B) a terrestrial animal such as a snake C) a red blood cell surrounded by plasma D) a lymphocyte before it has been taken back into lymph fluid E) a plant being grown hydroponically (in a watery mixture of designated nutrients)
B
Of the following functions, the major purpose of RNA is to A) transmit genetic information to offspring. B) function in the synthesis of protein. C) make a copy of itself, thus ensuring genetic continuity. D) act as a pattern or blueprint to form DNA. E) form the genes of higher organisms.
B
Polysaccharides, lipids, and proteins are similar in that they A) are synthesized from monomers by the process of hydrolysis. B) are synthesized from monomers by dehydration reactions. C) are synthesized as a result of peptide bond formation between monomers. D) are decomposed into their subunits by dehydration reactions. E) all contain nitrogen in their monomer building blocks.
B
The R group or side chain of the amino acid serine is—CH2OH. The R group or side chain of the amino acid alanine is—CH3. Where would you expect to find these amino acids in a globular protein in aqueous solution? A) Serine would be in the interior, and alanine would be on the exterior of the globular protein. B) Alanine would be in the interior, and serine would be on the exterior of the globular protein. C) Both serine and alanine would be in the interior of the globular protein. D) Both serine and alanine would be on the exterior of the globular protein. E) Both serine and alanine would be in the interior and on the exterior of the globular protein.
B
The formulation of a model for a structure or for a process serves which of the following purposes? A) It asks a scientific question. B) It functions as a testable hypothesis. C) It records observations. D) It serves as a data point among results. E) It can only be arrived at after years of experimentation.
B
The liveris involved in detoxification of many poisons and drugs.Which of the following structures is primarily involved in this process and therefore abundant in liver cells? A) rough ER B) smooth ER C) Golgi apparatus D) Nuclear envelope E) Transport vesicles
B
The molecular formula for glucose is C6 H12O6. What would be the molecular formula for a molecule made by linking three glucose molecules together by dehydration reactions? A) C18H36O18 B) C18H30O15 C) C6H10O5 D) C18H10O15 E) C3H6O3
B
The α helix and the β pleated sheet are both common polypeptide forms found in which level of protein structure? A) primary B) secondary C) tertiary D) quaternary E) all of the above
B
Under which of the following conditions would you expect to find a cell with a predominance of free ribosomes? A) a cell that is secreting proteins B) a cell that is producing cytoplasmic enzymes C) a cell that is constructing its cell wall or extracellular matrix D) a cell that is digesting food particles E) a cell that is enlarging its vacuole
B
What is a triacylglycerol? A) a protein with tertiary structure B) a lipid made with three fatty acids and glycerol C) a lipid that makes up much of the plasma membrane D) a molecule formed from three alcohols by dehydration reactions E) a carbohydrate with three sugars joined together by glycosidic linkages
B
What is the structural feature that allows DNA to replicate? A) sugar-phosphate backbone B) complementary pairing of the nitrogenous bases C) disulfide bonding (bridging) of the two helixes D) twisting of the molecule to form an α helix E) three-component structure of the nucleotides
B
What is the term used for a protein molecule that assists in the properfolding of other proteins? A) tertiary protein B) chaperonin C) enzyme protein D) renaturing protein E) denaturing protein
B
What kinds of molecules pass through a cell membrane most easily? A) large and hydrophobic B) small and hydrophobic C) large polar D) ionic E) monosaccharides such as glucose
B
What maintains the secondary structure of a protein? A) peptide bonds B) hydrogen bonds C) disulfide bonds D) ionic bonds E) phosphodiester bonds
B
Which of the following are nitrogenous bases of the purine type? A) cytosine and guanine B) guanine and adenine C) adenine and thymine D) thymine and uracil E) uracil and cytosine
B
Which of the following are nitrogenous bases of the pyrimidine type? A) guanine and adenine B) cytosine and uracil C) thymine and guanine D) ribose and deoxyribose E) adenine and thymine
B
Which of the following is a characteristic feature of a carrier protein in a plasma membrane? A) It is a peripheral membrane protein. B) It exhibits a specificity for a particular type of molecule. C) It requires the expenditure of cellular energy to function. D) It works against diffusion. E) It has few, if any, hydrophobic amino acids.
B
Which of the following is a compartment that often takes up much of the volume of a plant cell? A) lysosome B) vacuole C) mitochondrion D) Golgi apparatus E) peroxisome
B
Which of the following is a diverse group of hydrophobic molecules? A) carbohydrates B) lipids C) proteins D) nucleic acids
B
Which of the following makes it necessary for animal cells, although they have no cell walls, to have intercellularjunctions? A) Cell membranes do not distinguish the types of ions and molecules passing through them. B) Large molecules, especially proteins, do not readily get through one, much less two adjacent cell membranes. C) Cell-to-cell communication requires physical attachment of one cell to another. D) Maintenance of connective tissue shape requires cells to adhere to one another. E) The relative shapelessness of animal cells requires a mechanism for keeping the cells aligned.
B
Which of the following relationships between cell structures and theirrespective functions is correct? A) cell wall: support, protection B) chloroplasts: chief sites of cellularrespiration C) chromosomes: cytoskeleton of the nucleus D) ribosomes: secretion E) lysosomes:formation of ATP
B
Which of the following statements about the 5ʹ end of a polynucleotide strand of DNA is correct? A) The 5ʹ end has a hydroxyl group attached to the number 5 carbon of ribose. B) The 5ʹ end has a phosphate group attached to the number 5 carbon of ribose. C) The 5ʹ end has thymine attached to the number 5 carbon of ribose. D) The 5ʹ end has a carboxyl group attached to the number 5 carbon of ribose. E) The 5ʹ end is the fifth position on one of the nitrogenous bases.
B
Which of the following uses the amino acid sequences of polypeptides to predict a proteinʹs three-dimensional structure? A) X-ray crystallography B) bioinformatics C) analysis of amino acid sequence of smallfragments D) NMRspectroscopy E) high-speed centrifugation
B
Which of the following would you expect to be a problem for someone with nonfunctional chloride channeling? A) inadequate secretion of mucus B) buildup of excessive secretions in organs such as lungs C) buildup of excessive secretions in glands such as the pancreas D) sweat that includes no NaCl E) mentalretardation due to low salt levels in brain tissue
B
White blood cells engulf bacteria through what process? A) exocytosis B) phagocytosis C) pinocytosis D) osmosis E) receptor-mediated exocytosis
B
Why is it important to know what microscopy method was used to prepare the images you wish to study? A) so that you can judge whetherthe images you are seeing are of cells or of organelles B) so that you can make a judgment about the likelihood of artifacts having been introduced in the preparation C) so that you can decide whetherthe image is actually of the size described D) so that you can know whetherto view the image in color or not E) so that you can interpret the correct biochemical process that is occurring
B
Why isnʹt the mitochondrion classified as part of the endomembrane system? A) It only has two membrane layers. B) Its structure is not derived from the ER. C) It has too many vesicles. D) It is not involved in protein synthesis. E) It is not attached to the outer nuclear envelope.
B
A newspaper ad for a local toy store indicates that a very inexpensive microscope available for a small child is able to magnify specimens nearly as much as the much more costly microscope available in your college lab. What is the primary reason forthe price difference? A) The ad agency is misrepresenting the ability of the toy microscope to magnify. B) The toy microscope does not have the same fine control forfocus of the specimen. C) The toy microscope magnifies a good deal, but has low resolution and therefore poor quality images. D) The college microscope produces greater contrast in the specimens. E) The toy microscope usually uses a different wavelength of light source.
C
All of the following serve an importantrole in determining or maintaining the structure of plant cells.Which of the following are distinct from the others in their composition? A) microtubules B) microfilaments C) plant cell walls D) intermediate filaments E) nuclearlamina
C
At which level of protein structure are interactions between the side chains (Rgroups) most important? A) primary B) secondary C) tertiary D) quaternary E) all of the above
C
Cell membranes are asymmetrical.Which of the following is a most likely explanation? A) The cell membrane forms a border between one cell and another in tightly packed tissues such as epithelium. B) Cell membranes communicate signals from one organism to another. C) Cell membrane proteins are determined as the membrane is being packaged in the ER and Golgi. D) The ʺinnernessʺ and ʺouternessʺ of membrane surfaces are predetermined by genes. E) Proteins can only span cell membranes if they are hydrophobic.
C
Chloride ion channels are membrane structures that include which of the following? A) gap junctions B) aquaporins C) hydrophilic proteins D) carbohydrates E) sodium ions
C
Enzymes are A) carbohydrates. B) lipids. C) proteins. D) nucleic acids
C
For this pair of items, choose the option that best describes their relationship. (A) The probability of finding chitin in fungal cell walls (B) The probability of finding chitin in arthropod exoskeletons A) Item (A) is greaterthan item (B). B) Item (A) is lessthan item (B). C) Item (A) is exactly or very approximately equal to item (B). D) Item (A) may stand in more than one of the above relations to item (B).
C
Humans can digest starch but not cellulose because A) the monomer of starch is glucose, while the monomer of cellulose is galactose. B) humans have enzymes that can hydrolyze the beta (β) glycosidic linkages of starch but not the alpha (α) glycosidic linkages of cellulose. C) humans have enzymes that can hydrolyze the alpha (α) glycosidic linkages of starch but not the beta (β) glycosidic linkages of cellulose. D) humans harbor starch-digesting bacteria in the digestive tract. E) the monomer of starch is glucose, while the monomer of cellulose is maltose.
C
If a modern electron microscope (TEM) can resolve biological images to the nanometer level, as opposed to the best light microscope, this is due to which of the following? A) The focal length of the electron microscope is significantly longer. B) Contrast is enhanced by staining with atoms of heavy metal. C) Electron beams have much shorter wavelengths than visible light. D) The electron microscope has much greaterratio of image size to real size. E) The electron microscope cannot image whole cells at one time.
C
In orderfor a protein to be an integral membrane protein it would have to be which of the following? A) hydrophilic B) hydrophobic C) amphipathic D) completely covered with phospholipids E) exposed on only one surface of the membrane
C
In receptor-mediated endocytosis,receptor molecules initially project to the outside of the cell.Where do they end up after endocytosis? A) on the outside of vesicles B) on the inside surface of the cell membrane C) on the inside surface of the vesicle D) on the outer surface of the nucleus E) on the ER
C
Large numbers ofribosomes are present in cells that specialize in producing which of the following molecules? A) lipids B) starches C) proteins D) steroids E) glucose
C
Of the following molecules of the ECM, which is capable of transmitting signals between the ECM and the cytoskeleton? A) fibronectin B) proteoglycans C) integrins D) collagen E) middle lamella
C
Plasmodesmata in plant cells are most similarin function to which of the following structures in animal cells? A) peroxisomes B) desmosomes C) gap junctions D) extracellular matrix E) tight junctions
C
Tay-Sachs disease is a human genetic abnormality thatresults in cells accumulating and becoming clogged with very large and complex lipids.Which cellular organelle must be involved in this condition? A) the endoplasmic reticulum B) the Golgi apparatus C) the lysosome D) mitochondria E) membrane-bound ribosomes
C
The advantage of light microscopy over electron microscopy is that A) light microscopy provides for higher magnification than electron microscopy. B) light microscopy provides for higherresolving powerthan electron microscopy. C) light microscopy allows one to view dynamic processes in living cells. D) A and B E) B and C
C
The movement of potassium into an animal cellrequires A) low cellular concentrations of sodium. B) high cellular concentrations of potassium. C) an energy source such as ATP or a proton gradient. D) a cotransport protein. E) a gradient of protons across the plasma membrane.
C
The nuclearlamina is an array of filaments on the inner side of the nuclear membrane.If a method were found that could cause the lamina to fall into disarray, what would you expect to be the most likely consequence? A) the loss of all nuclearfunction B) the inability of the cell to withstand enzymatic digestion C) a change in the shape of the nucleus D) failure of chromosomes to carry genetic information E) inability of the nucleus to keep out destructive chemicals
C
The sodium-potassium pump is called an electrogenic pump because it A) pumps equal quantities of Na+ and K+ across the membrane. B) pumps hydrogen ions out of the cell. C) contributes to the membrane potential. D) ionizes sodium and potassium atoms. E) is used to drive the transport of other molecules against a concentration gradient.
C
The tertiary structure of a protein is the A) bonding together of several polypeptide chains by weak bonds. B) order in which amino acids are joined in a polypeptide chain. C) unique three-dimensional shape of the fully folded polypeptide. D) organization of a polypeptide chain into an α helix or β pleated sheet. E) overall protein structure resulting from the aggregation of two or more polypeptide subunits.
C
The volume enclosed by the plasma membrane of plant cells is often much larger than the corresponding volume in animal cells. The most reasonable explanation for this observation is that A) plant cells are capable of having a much higher surface-to-volume ratio than animal cells. B) plant cells have a much more highly convoluted (folded) plasma membrane than animal cells. C) plant cells contain a large vacuole thatreduces the volume of the cytoplasm. D) animal cells are more spherical, while plant cells are elongated. E) the basic functions of plant cells are very different from those of animal cells.
C
There are 20 different amino acids.What makes one amino acid different from another? A) different carboxyl groups attached to an alpha (α) carbon B) different amino groups attached to an alpha (α) carbon C) different side chains (Rgroups) attached to an alpha (α) carbon D) different alpha (α) carbons E) different asymmetric carbons
C
What is the chemical mechanism by which cells make polymers from monomers? A) phosphodiesterlinkages B) hydrolysis C) dehydration reactions D) ionic bonding of monomers E) the formation of disulfide bridges between monomers
C
What is the voltage across a membrane called? A) water potential B) chemical gradient C) membrane potential D) osmotic potential E) electrochemical gradient
C
What method did Frederick Sanger use to elucidate the structure of insulin? A) X-ray crystallography B) bioinformatics C) analysis of amino acid sequence of smallfragments D) NMRspectroscopy E) high-speed centrifugation
C
When a potassium ion (K+) moves from the soil into the vacuole of a cell on the surface of a root, it must pass through several cellular structures.Which of the following correctly describes the orderin which these structures will be encountered by the ion? A) plasma membrane → primary cell wall → cytoplasm → tonoplast B) secondary cell wall → plasma membrane → primary cell wall → cytoplasm → tonoplast C) primary cell wall → plasma membrane → cytoplasm → tonoplast D) primary cell wall → plasma membrane → tonoplast → cytoplasm → vacuole E) tonoplast→ primary cell wall → plasma membrane → cytoplasm
C
When biologists wish to study the internal ultrastructure of cells, they most likely would use A) a light microscope. B) a scanning electron microscope. C) a transmission electronic microscope. D) A and B E) B and C
C
Which is one of the main energy transformers of cells? A) lysosome B) vacuole C) mitochondrion D) Golgi apparatus E) peroxisome
C
Which of the following contains its own DNA and ribosomes? A) lysosome B) vacuole C) mitochondrion D) Golgi apparatus E) peroxisome
C
Which of the following descriptions bestfits the class of molecules known as nucleotides? A) a nitrogenous base and a phosphate group B) a nitrogenous base and a pentose sugar C) a nitrogenous base, a phosphate group, and a pentose sugar D) a phosphate group and an adenine or uracil E) a pentose sugar and a purine or pyrimidine
C
Which of the following is true of integral membrane proteins? A) They lack tertiary structure. B) They are loosely bound to the surface of the bilayer. C) They are usually transmembrane proteins. D) They are not mobile within the bilayer. E) They serve only a structural role in membranes.
C
Which of the following is true regarding saturated fatty acids? A) They are the predominant fatty acid in corn oil. B) They have double bonds between carbon atoms of the fatty acids. C) They are the principal molecules in lard and butter. D) They are usually liquid at room temperature. E) They are usually produced by plants.
C
Which of the following membrane activities require energy from ATP hydrolysis? A) facilitated diffusion. B) movement of waterinto a cell C) Na+ ions moving out of the cell D) movement of glucose molecules E) movement of waterinto a paramecium
C
Which of the following statements about the cytoskeleton is true? A) The dynamic aspect of cytoskeletal function is made possible by the assembly and disassembly of a large number of complex proteins into larger aggregates. B) Microfilaments are structurally rigid and resist compression, while microtubules resist tension (stretching). C) Movement of cilia and flagella is the result of motor proteins causing microtubules to move relative to each other. D) Chemicals that block the assembly of the cytoskeleton would cause little effect on the cellʹs metabolism E) Transport vesicles among the membranes of the endomembrane system produce the cytoskeleton
C
Which of the following statements best summarizes the structural differences between DNA andRNA? A) RNA is a protein, whereas DNA is a nucleic acid. B) DNA is a protein, whereasRNA is a nucleic acid. C) DNA nucleotides contain a different sugarthanRNA nucleotides. D) RNA is a double helix, but DNA is single-stranded. E) A and D are correct
C
Which of the following statements correctly describes some aspect of protein disposal from prokaryotic cells? A) Prokaryotes are unlikely to be able to excrete proteins because they lack an endomembrane system. B) The mechanism of protein excretion in prokaryotes is probably the same as that in eukaryotes. C) Proteins that are excreted by prokaryotes are synthesized on ribosomes that are bound to the cytoplasmic surface of the plasma membrane. D) In prokaryotes, the ribosomes that are used forthe synthesis of secreted proteins are located outside of the cell. E) Prokaryotes contain large pores in their plasma membrane that permit the movement of proteins out of the cell.
C
Which of the following statements is correct about diffusion? A) It is very rapid overlong distances. B) Itrequires an expenditure of energy by the cell. C) It is a passive process in which molecules move from a region of higher concentration to a region of lower concentration. D) It is an active process in which molecules move from a region of lower concentration to one of higher concentration. E) It requires integral proteins in the cell membrane.
C
Which of the following types of molecules are the major structural components of the cell membrane? A) phospholipids and cellulose B) nucleic acids and proteins C) phospholipids and proteins D) proteins and cellulose E) glycoproteins and cholesterol
C
Which of these are not embedded in the lipid bilayer at all? A) transmembrane proteins B) integral proteins C) peripheral proteins D) integrins E) glycoproteins
C
Which type of organelle is primarily involved in the synthesis of oils, phospholipids, and steroids? A) ribosome B) lysosome C) smooth endoplasmic reticulum D) mitochondrion E) contractile vacuole
C
Why are lipids and proteins free to move laterally in membranes? A) The interior of the membrane is filled with liquid water. B) There are no covalent bonds between lipid and protein in the membrane. C) Hydrophilic portions of the lipids are in the interior of the membrane. D) There are only weak hydrophobic interactions in the interior of the membrane. E) Molecules such as cellulose can pull them in various directions.
C
he difference in lipid and protein composition between the membranes of the endomembrane system is largely determined by A) the physical separation of most membranes from each other. B) the transportation of membrane among the endomembrane system by small membrane vesicles. C) the function of the Golgi apparatus in sorting membrane components. D) the modification of the membrane components once they reach their final destination. E) the synthesis of lipids and proteins in each of the organelles of the endomembrane system.
C
A biologist ground up some plant leaf cells and then centrifuged the mixture to fractionate the organelles. Organelles in one of the heavier fractions could produce ATP in the light, while organelles in the lighter fraction could produce ATP in the dark. The heavier and lighter fractions are most likely to contain,respectively, A) mitochondria and chloroplasts. B) chloroplasts and peroxisomes. C) peroxisomes and chloroplasts. D) chloroplasts and mitochondria. E) mitochondria and peroxisomes.
D
A cell has the following molecules and structures: enzymes, DNA,ribosomes, plasma membrane, and mitochondria.It could be a cell from A) a bacterium. B) an animal, but not a plant. C) a plant, but not an animal. D) a plant or an animal. E) any kind of organism.
D
A cell lacking the ability to make and secrete glycoproteins would most likely be deficient in its A) nuclear DNA. B) extracellular matrix. C) Golgi apparatus. D) B and C only E) A, B, and C
D
A primary objective of cell fractionation is to A) view the structure of cell membranes. B) identify the enzymes outside the organelles. C) determine the size of various organelles. D) separate the major organelles so that their particular functions can be determined. E) crack the cell wall so the cytoplasmic contents can be released.
D
A strong covalent bond between amino acids that functions in maintaining a polypeptideʹs specific three-dimensional shape is a (an) A) ionic bond. B) hydrophobic interaction. C) van der Waals interaction. D) disulfide bond. E) hydrogen bond.
D
After a membrane freezes and then thaws, it often becomes leaky to solutes. The most reasonable explanation forthis is that A) transport proteins become nonfunctional during freezing. B) the lipid bilayerloses its fluidity when it freezes. C) aquaporins can no longerfunction afterfreezing. D) the integrity of the lipid bilayeris broken when the membrane freezes. E) the solubility of most solutes in the cytoplasm decreases on freezing
D
An organism with a cell wall would have the most difficulty doing which process? A) diffusion B) osmosis C) active transport D) phagocytosis E) facilitated diffusion
D
Cells require which of the following to form cilia orflagella? A) centrosomes B) ribosomes C) actin D) A and B only E) A, B, and C
D
How does the cell multiply its peroxisomes? A) They bud off from the ER. B) They are brought into the cell from the environment. C) They are built de novo from cytosol materials. D) They split in two after they are too large. E) The cell synthesizes hydrogen peroxide and encloses it in a membrane.
D
If a young male child has cystic fibrosis, which of the following would affect his fertility? A) inability to make sperm B) incomplete maturation of the testes C) failure to form genital structures appropriately D) incorrect concentrations of ions in semen E) abnormal pH in seminalfluid
D
If an individual has abnormal microtubules, due to a hereditary condition, in which organs ortissues would you expect dysfunction? A) limbs, hearts, areas with a good deal of contraction B) microvilli, alveoli, and glomeruli C) all ducts, such as those from salivary or sebaceous glands D) sperm, larynx, and trachea E) egg cells (ova), uterus, and kidneys
D
In the years since the proposal of the fluid mosaic model of the cell membrane, which of the following observations has been added to the model? A) The membrane is only fluid across a very narrow temperature range. B) Proteins rarely move, even though they possibly can do so. C) Unsaturated lipids are excluded from the membranes. D) The concentration of protein molecules is now known to be much higher. E) The proteins are known to be made of only acidic amino acids.
D
Ions diffuse across membranes down their A) chemical gradients. B) concentration gradients. C) electrical gradients. D) electrochemical gradients. E) A and B are correct.
D
Lactose, a sugarin milk, is composed of one glucose molecule joined by a glycosidic linkage to one galactose molecule. How is lactose classified? A) as a pentose B) as a hexose C) as a monosaccharide D) as a disaccharide E) as a polysaccharide
D
Misfolding of polypeptides is a serious problem in cells.Which of the following diseases are associated with an accumulation of misfolded proteins? A) Alzheimerʹs B) Parkinsonʹs C) diabetes D) A and B only E) A, B, and C
D
Motor proteins provide for molecular motion in cells by interacting with what types of cellular structures? A) sites of energy production in cellularrespiration B) membrane proteins C) ribosomes D) cytoskeletons E) cellulose fibers in the cell wall
D
Organelles otherthan the nucleus that contain DNA include A) ribosomes. B) mitochondria. C) chloroplasts. D) B and C only E) A, B, and C
D
Proton pumps are used in various ways by members of every kingdom of organisms.What does this most probably mean? A) Proton pumps must have evolved before any living organisms were present on the earth. B) Proton pumps are fundamental to all cell types. C) The high concentration of protons in the ancient atmosphere must have necessitated a pump mechanism. D) Cells with proton pumps were maintained in each Kingdom by natural selection. E) Proton pumps are necessary to all cell membranes.
D
Quantum dots are small(15—30 nm diameter), bright particles visible using light microscopy.If the dots can be specifically bound to individual proteins on a plasma membrane of a cell, which of the following correctly describes the advantage of using quantum dots in examining proteins? A) The dots permit the position of the proteins to be determined more precisely. B) The dots permit the average distance between the proteins to be determined more precisely. C) The dots permit the size of the proteins to be determined more precisely. D) The dots permit the motion of the proteins to be determined more precisely. E) The dots permit visualization of proteins interacting with lipids.
D
The cell walls of bacteria, fungi, and plant cells and the extracellular matrix of animal cells are all external to the plasma membrane.Which of the following is a characteristic of all of these extracellular structures? A) They must block water and small molecules in order to regulate the exchange of matter and energy with their environment. B) They must permit information transfer between the cellʹs cytoplasm and the nucleus. C) They must provide a rigid structure that maintains an appropriate ratio of cell surface area to volume. D) They are constructed of materials that are largely synthesized in the cytoplasm and then transported out of the cell. E) They are composed of a mixture of lipids and carbohydrates.
D
The chemicalreactions involved in respiration are virtually identical between prokaryotic and eukaryotic cells.In eukaryotic cells, ATP is synthesized primarily on the inner membrane of the mitochondria.Where are the corresponding reactions likely to occurin prokaryotic respiration? A) in the cytoplasm B) on the inner mitochondrial membrane C) on the endoplasmic reticulum D) on the inner plasma membrane E) on the inner nuclear envelope
D
The extracellular matrix is thought to participate in the regulation of animal cell behavior by communicating information from the outside to the inside of the cell via which of the following? A) gap junctions B) the nucleus C) DNA andRNA D) integrins E) plasmodesmata
D
The peroxisome gets its name from its interaction with hydrogen peroxide.If a liver cell is detoxifying alcohol and some other poisons, it does so by removal of hydrogen from the molecules.What, then, do the enzymes of the peroxisome do? A) combine the hydrogen with ATP B) use the hydrogen to break down hydrogen peroxide C) transferthe harmful substances to the mitochondria D) transferthe hydrogens to oxygen molecules
D
When a membrane is freeze-fractured, the bilayer splits down the middle between the two layers of phospholipids.In an electron micrograph of a freeze-fractured membrane, the bumps seen on the fractured surface of the membrane are A) peripheral proteins. B) phospholipids. C) carbohydrates. D) integral proteins. E) cholesterol molecules.
D
Which of the following contain the 9 + 2 arrangement of microtubules? A) cilia B) centrioles C) flagella D) A and C only E) A, B, and C
D
Which of the following is a major cause of the size limits for certain types of cells? A) the evolution of larger cells afterthe evolution of smaller cells B) the difference in plasma membranes between prokaryotes and eukaryotes C) the evolution of eukaryotes afterthe evolution of prokaryotes D) the need for a surface area of sufficient area to allow the cellʹs function E) the observation that longer cells usually have greater cell volume
D
Which of the following is an example of hydrolysis? A) the reaction of two monosaccharides,forming a disaccharide with the release of water B) the synthesis of two amino acids,forming a peptide with the release of water C) the reaction of a fat, forming glycerol and fatty acids with the release of water D) the reaction of a fat, forming glycerol and fatty acids with the utilization of water E) the synthesis of a nucleotide from a phosphate, a pentose sugar, and a nitrogenous base with the production of a molecule of water
D
Which of the following is true of cellulose? A) It is a polymer composed of sucrose monomers. B) It is a storage polysaccharide for energy in plant cells. C) It is a storage polysaccharide for energy in animal cells. D) It is a major structural component of plant cell walls. E) It is a major structural component of animal cell plasma membranes
D
Which of the following is true of the evolution of cell membranes? A) Cell membranes have stopped evolving now that they are fluid mosaics. B) Cell membranes cannot evolve if proteins do not. C) The evolution of cell membranes is driven by the evolution of glycoproteins and glycolipids. D) As populations of organisms evolve, different properties of their cell membranes are selected for or against. E) An individual organism selects its preferred type of cell membrane for particular functions.
D
Which of the following polymers contain nitrogen? A) starch B) glycogen C) cellulose D) chitin E) amylopectin
D
Which of the following produces and modifies polysaccharides that will be secreted? A) lysosome B) vacuole C) mitochondrion D) Golgi apparatus E) peroxisome
D
Which of the following store and transmit hereditary information? A) carbohydrates B) lipids C) proteins D) nucleic acids
D
Which of these are attached to the extracellular matrix? A) transmembrane proteins B) integral proteins C) peripheral proteins D) integrins E) glycoproteins
D
Which type of interaction stabilizes the alpha (α) helix and the beta (β) pleated sheet structures of proteins? A) hydrophobic interactions B) nonpolar covalent bonds C) ionic bonds D) hydrogen bonds E) peptide bonds
D
Who proposed that the membrane is a mosaic of protein molecules bobbing in a fluid bilayer of phospholipids? A) H. Davson and J. Danielli B) I. Langmuir C) C. Overton D) S. Singer and G. Nicolson E) E. Gorter and F. Grendel
D
A biologist is studying kidney tubules in small mammals. She wants specifically to examine the juxtaposition of different types of cells in these structures. The cells in question can be distinguished by external shape, size, and 3-dimensional characteristics.Which would be the optimum method for her study? A) transmission electron microscopy B) cell fractionation C) light microscopy using stains specific to kidney function D) light microscopy using living unstained material E) scanning electron microscopy
E
A molecule with the chemical formula C6 H12O6 is probably a A) carbohydrate. B) lipid. C) monosaccharide D) A and B only. E) A, B, and C.
E
A mycoplasma is an organism with a diameter between 0.1 and 1.0 μm.What does its size tell you about how it might be classified? A) It must be a single celled protist. B) It must be a single celled fungus. C) It could be almost any typical bacterium. D) It could be a typical virus. E) It could be a very small bacterium.
E
All of the following are part of aprokaryotic cellexcept A) DNA. B) a cell wall. C) a plasma membrane. D) ribosomes. E) an endoplasmic reticulum
E
Altering which of the following levels of structural organization could change the function of a protein? A) primary B) secondary C) tertiary D) quaternary E) all of the above
E
Centrioles, cilia, flagella, and basal bodies have remarkably similar structural elements and arrangements. This leads us to which of the following as a probable hypothesis? A) Disruption of one of these types of structure should necessarily disrupt each of the others as well. B) Loss of basal bodies should lead to loss of all cilia, flagella, and centrioles. C) Motor proteins such as dynein must have evolved before any of these four kinds of structure. D) Evolution of motility, of cells or of parts of cells, must have occurred only once. E) Natural selection for motility must select for microtubular arrays in circular patterns
E
Dehydration reactions are used in forming which of the following compounds? A) triacylglycerides B) polysaccharides C) proteins D) A and C only E) A, B, and C
E
Glucose diffuses slowly through artificial phospholipid bilayers. The cells lining the small intestine, however,rapidly move large quantities of glucose from the glucose-rich food into their glucose-poor cytoplasm. Using this information, which transport mechanism is most probably functioning in the intestinal cells? A) simple diffusion B) phagocytosis C) active transport pumps D) exocytosis E) facilitated diffusion
E
If a membrane protein in an animal cell is involved in the cotransport of glucose and sodium ions into the cell, which of the following is most likely true? A) The sodium ions are moving down their electrochemical gradient while glucose is moving up. B) Glucose is entering the cell along its concentration gradient. C) Sodium ions can move down their electrochemical gradient through the cotransporter whether or not glucose is present outside the cell. D) Potassium ions move across the same gradient as sodium ions. E) A substance that blocked sodium ions from binding to the cotransport protein would also block the transport of glucose.
E
In the double helix structure of nucleic acids, cytosine hydrogen bonds to A) deoxyribose. B) ribose. C) adenine. D) thymine. E) guanine.
E
Ions can travel directly from the cytoplasm of one animal cell to the cytoplasm of an adjacent cell through A) plasmodesmata. B) intermediate filaments. C) tight junctions. D) desmosomes. E) gap junctions
E
Microfilaments are well known fortheirrole in which of the following? A) ameboid movement B) formation of cleavage furrows C) contracting of muscle cells D) A and B only E) A, B, and C
E
Of the following functions, which is most important forthe glycoproteins and glycolipids of animal cell membranes? A) facilitated diffusion of molecules down their concentration gradients B) active transport of molecules against their concentration gradients C) maintaining the integrity of a fluid mosaic membrane D) maintaining membrane fluidity at low temperatures E) a cellʹs ability to distinguish one type of neighboring cell from another
E
Recent evidence shows that individual chromosomes occupy fairly defined territories within the nucleus. Given the structure and location of the following parts of the nucleus, which would be more probably involved in chromosome location? A) nuclear pores B) the nucleolus C) the outerlipid bilayer D) the nuclearlamina E) the nuclear matrix
E
Several seriously epidemic viral diseases of earlier centuries were then incurable because they resulted in severe dehydration due to vomiting and diarrhea. Today they are usually not fatal because we have developed which of the following? A) antiviral medications that are efficient and work well with all viruses B) antibiotics against the viruses in question C) intravenous feeding techniques D) medication to prevent blood loss E) hydrating drinks that include high concentrations of salts and glucose
E
The Golgi apparatus has a polarity or sidedness to its structure and function. Which of the following statements correctly describes this polarity? A) Transport vesicles fuse with one side of the Golgi and leave from the opposite side. B) Proteins in the membrane of the Golgi may be sorted and modified as they move from one side of the Golgi to the other. C) Lipids in the membrane of the Golgi may be sorted and modified as they move from one side of the Golgi to the other. D) Soluble proteins in the cisternae (interior) of the Golgi may be sorted and modified as they move from one side of the Golgi to the other. E) All of the above correctly describe polar characteristics of the Golgi function.
E
The difference between the sugar in DNA and the sugar in RNA is that the sugar in DNA A) is a six-carbon sugar and the sugar in RNA is a five-carbon sugar. B) can form a double-stranded molecule. C) has a six-membered ring of carbon and nitrogen atoms. D) can attach to a phosphate. E) contains one less oxygen atom.
E
The element nitrogen is present in all of the following except A) proteins. B) nucleic acids. C) amino acids. D) DNA. E) monosaccharides
E
The function of each protein is a consequence of its specific shape.What is the term used for a change in a proteinʹs three-dimensional shape or conformation due to disruption of hydrogen bonds, disulfide bridges, orionic bonds? A) hydrolysis B) stabilization C) destabilization D) renaturation E) denaturation
E
The hydrogenation of vegetable oilresults in which of the following? A) saturated fats and unsaturated fats with transdouble bonds B) an increased contribution to artherosclerosis C) the oil (fat) being a solid atroom temperature D) A and C only E) A, B, and C
E
Water passes quickly through cell membranes because A) the bilayeris hydrophilic. B) it moves through hydrophobic channels. C) water movement is tied to ATP hydrolysis. D) it is a small, polar, charged molecule. E) it moves through aquaporins in the membrane.
E
What are the membrane structures that function in active transport? A) peripheral proteins B) carbohydrates C) cholesterol D) cytoskeleton filaments E) integral proteins
E
What mechanisms do plants use to load sucrose produced by photosynthesis into specialized cells in the veins of leaves? A) an electrogenic pump B) a proton pump C) a contransport protein D) A and C only E) A, B, and C
E
What would be an unexpected consequence of changing one amino acid in a protein consisting of 325 amino acids? A) The primary structure of the protein would be changed. B) The tertiary structure of the protein might be changed. C) The biological activity orfunction of the protein might be altered. D) Only A and C are correct. E) A, B, and C are correct.
E
When a plant cell, such as one from a peony stem, is submerged in a very hypotonic solution, what is likely to occur? A) the cell will burst B) the cell membrane will lyse C) plasmolysis will shrink the interior D) the cell will become flaccid E) the cell will become turgid
E
When biological membranes are frozen and then fractured, they tend to break along the middle of the bilayer. The best explanation for this is that A) the integral membrane proteins are not strong enough to hold the bilayer together. B) water that is present in the middle of the bilayer freezes and is easily fractured. C) hydrophilic interactions between the opposite membrane surfaces are destroyed on freezing. D) the carbon-carbon bonds of the phospholipid tails are easily broken. E) the hydrophobic interactions that hold the membrane together are weakest at this point.
E
Which of the following best summarizes the relationship between dehydration reactions and hydrolysis? A) Dehydration reactions assemble polymers, and hydrolysis reactions break down polymers. B) Macromolecular synthesis occurs through the removal of water and digestion occurs through the addition of water. C) Dehydration reactions can occur only after hydrolysis. D) Hydrolysis creates monomers, and dehydration reactions break down polymers. E) A and B are correct
E
Which of the following contains enzymes that transfer hydrogen from various substrates to oxygen? A) lysosome B) vacuole C) mitochondrion D) Golgi apparatus E) peroxisome
E
Which of the following correctly lists the orderin which cellular components will be found in the pellet when homogenized cells are treated with increasingly rapid spins in a centrifuge? A) ribosomes, nucleus, mitochondria B) chloroplasts,ribosomes, vacuoles C) nucleus,ribosomes, chloroplasts D) vacuoles,ribosomes, nucleus E) nucleus, mitochondria,ribosomes
E
Which of the following descriptors is true of the molecule shown in Figure 5.1? A) hexose B) fructose C) glucose D) A and B only E) A and C only
E
Which of these often serve as receptors or cellrecognition molecules on cell surfaces? A) transmembrane proteins B) integral proteins C) peripheral proteins D) integrins E) glycoproteins
E
Who was/were the first to propose that cell membranes are phospholipid bilayers? A) H. Davson and J. Danielli B) I. Langmuir C) C. Overton D) S. Singer and G. Nicolson E) E. Gorter and F. Grendel
E