Cell Phys-CH 1, 3, 5, 7, 8
A negative free energy change indicates that? A) the reaction is not possible. B) the reaction is at equilibrium. C) the reaction is exothermic. D) energy must be added to the reaction before it can proceed. E) the reactant is predominant at equilibrium.
C
All of the following are active transporters except? A) symporters. B) ABC transporters. C) permeases. D) P-class pumps. E) bacteriorhodopsin.
C
Animals that regulate their body temperature independently of the environment are called A) biotherms. B) poikilotherms. C) homeotherms. D) heterotherms. E) abiotherms.
C
A spontaneous reaction? A) will never occur. B) could occur but might take a very long time. C) is associated exclusively with homeothermic organisms. D) has to occur immediately. E) has an overall positive free energy change.
B
A student drops his notes, and his papers scatter. The fact that the papers scatter and do not remain neatly stacked is an illustration of? A) an increase in entropy. B) an increase in entropy as predicted by the second law of thermodynamics. C) the first law of thermodynamics. D) the second law of thermodynamics. E) both the first and second laws of thermodynamics.
B
Which of the following statements is false concerning the value ΔH? A) In biology, ΔH is basically the same as ΔE. B) ΔH is the change in heat content. C) A reaction with a positive ΔH value is exothermic. D) ΔH is the change in enthalpy. E) ΔH = ΔE + Δ(PV)
C
Which type of microscopy enhances and amplifies slight changes in the phase of transmitted light? A) phase-contrast microscopy B) differential interference contrast microscopy C) both differential interference contrast microscopy and phase-contrast microscopy D) digital video microscopy E) fluorescence microscopy
C
In a cell, the concentration of glucose-6-phosphate is 83 μM and of fructose-6-phosphate is 1 μM. The ΔG°' = 410 cal/mol for the conversion of glucose-6-phosphate to fructose-6-phosphate. Based upon this information, the ΔG' for this reaction (in cal/mol) is? A) 27. B) 644. C) 0.D) −644. E) −63.7.
D
In a chemical reaction at equilibrium, the concentration of R (the reactant) is 3.0 mol/L and the concentration of P (the product) is 0.9 mol/L. At 25°C, what would be the Keq? A) 37.5 B) 1.5 C) 1.0 D) 0.3 E) 3.0
D
In a reversible chemical reaction at equilibrium, the concentration of X (the reactant) is 0.75 mol/L, and the concentration of Y (the product) is 2.25 mol/L. At 25°C, what would be the Keq? A) 1.50 B) 1.69 C) 37.5 D) 3.0 E) 0.33
D
Once a scientific theory becomes a law, it? A) becomes static. B) cannot be challenged. C) is irrefutable. D) is subject to modification. E) cannot be changed.
D
One way in which ions are specifically transported into the cell is via? A) simple diffusion. B) carrier (permease) proteins. C) uniport transporters. D) gated channels. E) ABC transporters.
D
RNA and DNA differ? A) in that RNA contains uracil and DNA contains thymine. B) in that RNA contains nucleosides and DNA contains nucleotides. C) in that RNA contains ribose and DNA contains deoxyribose. D) both A and C. E) All of these are correct.
D
Reduction involves the? A) gain of electrons and an increase in oxidation state. B) loss of neutrons, gain of electrons, and an increase in oxidation state. C) loss of neutrons. D) gain of electrons. E) increase in oxidation state.
D
Which of the following is an example of indirect active transport? A) glucose permease transport B) aquaporin water transport C) Na+/K+ ATPase D) Na+/glucose symport E) CFTR Cl− transport
D
Which of the following is not a basic need of the cell? A) energy B) molecular building blocks C) chemical catalysts D) 100% efficiency E) information
D
Which of the following is not a major functional class of proteins? A) enzymes B) motility proteins C) regulatory proteins D) hereditary proteins E) structural proteins
D
Which of the following is smallest? A) prokaryote B) mitochondrion C) virus D) protein E) ribosome
D
The scientific work that established DNA, rather than protein, as the molecule of heredity was performed prior to? A) the formation of the chromosome theory of heredity. B) Antonie van Leeuwenhoek's observation of internal cell structures. C) the description of the enzymatic steps of glycolysis. D) Mendel's work on heredity. E) the elucidation of the double helix structure of DNA.
E
The statement, "Energy is neither created nor destroyed," is a statement of? A) the first law of thermodynamics. B) enthalpy. C) entropy. D) the second law of thermodynamics. E) an early theory of energy that has now been proven false.
E
The term amphipathic describes the characteristic of some molecules that have? A) two nonpolar regions. B) no polar regions. C) only a single polar region. D) two polar regions. E) both a polar and a nonpolar region.
E
Trans fats? A) resemble saturated fatty acids in shape. B) are associated with an increased risk of heart disease. C) are unsaturated fatty acids. D) are present in small amounts in meat and dairy products. E) All of these statements are true.
E
What form of energy do all living organisms use? A) radiation B) nuclear energy C) heat D) sunlight E) chemical bonds
E
What is the free energy change for the inward movement of calcium ions into the bacterial cell? A) −9.2 kcal/mol; an endergonic reaction B) +4.6 kcal/mol; an exergonic reaction C) +9.2 kcal/mol; an exergonic reaction D) +4.6 kcal/mol; an endergonic reaction E) −9.2 kcal/mol; an exergonic reaction
E
When Peter Agre and colleagues compared frog oocytes expressing aquaporin with control oocytes lacking aquaporin placed in pure water, they found that? A) the control oocytes lacking aquaporin swelled and burst as water was transported into the cells. B) the oocytes expressing aquaporin first collapsed and then swelled as water was transported out and then back into the cells. C) the oocytes expressing aquaporin first swelled and then collapsed as water was transported into and then back out of the cells. D) the oocytes expressing aquaporin collapsed as water was transported out of the cells. E) the oocytes expressing aquaporin swelled and burst as water was transported into the cells.
E
Scanning electron microscopy (SEM) is especially suited to? A) creating a sense of depth. B) simultaneously observing living specimens, examining internal cellular structure, and creating a sense of depth. C) both observing living specimens and creating a sense of depth. D) examining internal cellular structure. E) observing living specimens.
A
The erythrocyte anion exchange protein "ping-pong" transport mechanism involves? A) unidirectional transport of Cl− only out of the cell. B) binding of Cl− on one side of the membrane. C) two conformational states of the protein. D) binding of bicarbonate ion on one side of the membrane. E) All are involved in the mechanism.
A
The graph above shows the initial rate of transport for each substance when the cells are placed in solutions of different concentrations of A, B, and C. Based on these data, substance A is transported via? A) simple diffusion. B) passive transport. C) active transport. D) symport. E) facilitated transport.
A
The technique that separates denatured proteins based on size is? A) SDS-PAGE. B) freeze-fracture microscopy. C) thin-layer chromatography. D) FRAP. E) Western blotting.
A
To which of the following classes of sugars does glucose belong? A) hexose B) triose C) heptose D) tetrose E) pentose
A
To which of the following do Mendel's observations relate? A) heredity B) diffusion C) gravity D) ideal gas laws E) thermodynamics
A
Water moves across the plasma membrane into or out of a cell by osmosis when? A) water diffuses through a semipermeable membrane toward a higher solute concentration. B) a high solute concentration opens an aquaporin channel. C) ATP hydrolysis drives aquaporin transport. D) there is an equal solute concentration on both sides of the membrane. E) water diffuses through a semipermeable membrane toward a lower solute concentration.
A
When ΔG' = 0 in a chemical reaction, under standard conditions? A) reactants and products are at equilibrium; no work can be done; no energy required. B) the reaction is spontaneous to the left. C) work can be done; energy is required. D) reactants and products are at equilibrium. E) no work can be done; no energy is required.
A
Which is true of heterotrophs? A) They can obtain energy by consuming phototrophs. B) They cannot be unicellular. C) They store energy in the form of heat. D) They capture light energy. E) They can function as autotrophs in an emergency.
A
Which of the following diseases results from impaired glycosphingolipid degradation? A) Tay-Sachs disease B) heart disease C) glycosphingolipid anemia D) metabolic syndrome E) erythrocyte spherocytosis
A
Which of the following is a sterol-like lipid associated with plant cell membranes? A) phytosterol B) hopanoids C) palmitate D) linoleate E) stearate
A
Which of the following is an application of immunofluorescence microscopy? A) Identifying which organelle or cellular compartment contains a particular protein. B) Visualization of the natural fluorescence of a specimen under UV light. C) Identification of specific components of the immune system. D) Visualization of the surface structures of a specimen. E) Construction of three-dimensional images of structures smaller than 10 nm.
A
Which of the following is an important characteristic for a model organism? A) widely studied B) prone to random changes that alter primary characteristics C) difficult to manipulate in the laboratory D) marginally characterized E) all of the above
A
Which of the following is defined as "heat content"? A) enthalpy B) entropy C) solar radiation D) energy output E) heat loss
A
Which of the following is mismatched? A) Caenorhabditis elegans - photosynthesis B) Escherichia coli - genetics C) Drosophila melanogaster - embryogenesis D) Mus musculus - immunology E) Arabidopsis thaliana - plant gene function
A
Which of the following is not a steroid? A) phenylalanine B) estradiol C) aldosterone D) testosterone E) cortisol
A
Which of the following is not one of the six classes of lipids? A) pectins B) steroids C) fatty acids D) terpenes E) triacylglycerols
A
Which of the following lipids is found concentrated in lipid rafts in animal cell plasma membranes? A) cholesterol B) phosphatidylserine C) phophatidylethanolamine D) phosphatidylinositol E) phosphatidylcholine
A
Which of the following statements is false? A) All cells have a membrane-bound nucleus. B) Cells come in a wide variety of sizes and shapes. C) The cell is the basic unit of structure for all organisms. D) All organisms consist of one or more cells. E) All cells arise from preexisting cells.
A
Which of the following types of ATPase pumps are sensitive to vanadate (which inhibits phosphorylation of the pump during its activity mechanism)? A) P type B) ABC type C) F type D) V type E) All are inhibited by vanadate.
A
Which of the following types of light microscopy improves the resolution of thick specimens by illuminating one plane of the specimen at a time? A) confocal microscopy B) brightfield microscopy C) phase-contrast microscopy D) fluorescence microscopy E) differential interference contrast microscopy
A
Which of the following types of work involves a change in position of the cell or a cell structure? A) mechanical B) electrical C) bioluminescent D) concentration E) synthetic
A
Which of the following would best be used to determine the lipid content of an isolated membrane fraction? A) thin-layer chromatography B) Western blot analysis C) SDS-PAGE D) freeze-fracture analysis E) ferretin-linked antibodies
A
Which of the following would best detect a specific carbohydrate sugar on a glycoprotein? A) ferritin-conjugated lectins B) SDS-PAGE C) photobleaching D) thin-layer chromatography E) freeze-fracture microscopy
A
Which of the following would you expect to find predominating in the plasma membrane of a unicellular eukaryotic organism thriving in glacier ice? A) 16 carbon long fatty acids with 3 double bonds B) 18 carbon long fatty acids with 1 double bond. C) 20 carbon long saturated fatty acids. D) 18 carbon long saturated fatty acids. E) 20 carbon long fatty acids with 1 double bond.
A
A microtome is used to? A) slice thin sections of specimens. B) dissect cellular organelles. C) view microscopic organisms. D) focus short wavelengths of light. E) manipulate tiny objects.
A
A peptide bond? A) is a covalent bond between the carboxyl carbon of one amino acid and the amino nitrogen of a second amino acid. B) is a noncovalent bond that dictates the tertiary structure of a protein. C) is a covalent bond between the NH group of one polypeptide and the CO group of an adjacent polypeptide that holds together multimeric proteins. D) is a covalent bond between the functional R groups of adjacent amino acids. E) is a covalent bond between adjacent glucose molecules in a peptide.
A
All of the following are model organisms, except? A) Homo sapiens. B) Saccharomyces cerevisiae. C) Caenorhabditis elegans. D) Arabidopsis thialana. E) Drosophila melanogaster.
A
Assuming no change in either the internal or external calcium ion concentration, at what membrane potential would there be no net movement of calcium across the membrane? A) −50 mV B) 0 mV C) +25 mV D) −25 mV E) +50 mV
A
Complementary relationships between purines and pyrimidines? A) allow adenine to form two hydrogen bonds with thymine (or uracil) and guanine to form three hydrogen bonds with cytosine to form double-stranded nucleic acids. B) allow the interaction of the oppositely charged amino acids to form the tertiary structure of proteins. C) allow adjacent bases in a nucleotide chain to stack tightly, stabilizing the DNA double helix. D) provide highly ordered, repetitive bonding to form α helices and β sheets within proteins. E) Both A and C are correct.
A
Each of the following contributes to the system providing structural support to the erythrocyte plasma membrane except? A) the peripheral protein glyceraldehyde-3-phosphate dehydrogenase (GAPDH). B) the peripheral protein spectrin. C) short actin filaments. D) the peripheral protein ankyrin. E) the integral protein glycophorin.
A
Each of the following is a model for membrane structure except? A) Watson and Crick double helix. B) Singer and Nicholson fluid mosaic. C) Overton lipid coat. D) Gorter and Grendel bilayer. E) Langmuir monolayer.
A
Each of the following is typical characteristics of an integral membrane protein transmembrane segment except? A) amphipathic. B) composed primarily of hydrophobic amino acids. C) 20-30 amino acids long. D) α-helical structure. E) All are characteristics of a typical transmembrane segment.
A
Energy-requiring reactions can occur in biological systems because they can be coupled with reactions that are? A) exergonic. B) unlikely. C) spontaneous and endergonic. D) endergonic. E) not spontaneous.
A
Hopanoids are? A) related to cholesterol. B) a type of phospholipid. C) found exclusively in yeast. D) a type of glycolipid. E) All of the above are correct.
A
How does brightfield microscopy allow images to be visualized? A) Specimens are illuminated with white light. B) Electrons strike the specimen being examined. C) Specimens are illuminated with blue light to visualize internal features of cells smaller than 100 nm. D) Specimens are fixed and have bright fluorescent molecules attached to them. E) Specimens are viewed under phased light to improve magnification.
A
In a chemical reaction, the standard free energy change (ΔG°') is calculated to be −3.67 cal/mol. 16) What can be said of the chemical reaction? A) The reaction is spontaneous under standard conditions. B) The reaction is not spontaneous under standard conditions. C) The reaction is at equilibrium under standard conditions. D) Reactants predominate over products at equilibrium under standard conditions. E) There can be no reaction.
A
Individuals with the O blood group are known as universal donors because the Gal and GlcNAc 41) groups that are recognized by the antibodies in A, B, and AB in other individuals are missing. Which of which of the following types of erythrocyte plasma membrane components lacks these GlcNAc groups? A) a glycolipid B) a glycoprotein C) a GPI-anchored protein D) a glycocalyx protein E) glycophorin
A
Knowing the ion concentrations on both sides of the plasma membrane makes it possible to 11) calculate the membrane potential (Vm), because at equilibrium? A) ΔG is 0. B) ΔG is 1. C) the Faraday constant is 0. D) the Vm is always -60 mV. E) It is not possible to calculate Vm without also knowing the uncharged solute distribution across the membrane.
A
Lipid rafts are? A) regions of the membrane that are high in sphingolipids, which facilitate communication with the external environment of the cell. B) regions not typically associated with signal transduction. C) important regions of membrane structure comprised of phospholipids. D) rafts of lipids inside of the cell that serve to store energy. E) regions where greater concentrations of sphingolipids are on the inner side of the membrane.
A
Mutations in bacterial porins typically lead to antibiotic resistance by? A) blocking diffusion of the antibiotic through the porin channel. B) disrupting the voltage difference across the porin channel. C) changing the orientation of the porin α-helical transmembrane segments to constrict the size of the channel. D) reversing water transport through the channel. E) changing the stereoisomer specificity of the porin transport.
A
Naturally occurring unsaturated fatty acids typically? A) contain double bonds primarily in the cis configuration. B) contain double bonds primarily in the trans configuration. C) are omega-3 fatty acids. D) are highly branched. E) contain an odd number of carbon atoms.
A
Of the following molecules, which would you predict diffuses most readily across membranes? 5) A) oxygen B) hydrogen ions C) water D) glucose E) serine
A
Phosphorylation of glucose following its transport into a cell? A) increases glucose transport into the cell by increasing its concentration gradient across theplasma membrane. B) targets the glucose for transport back out of the cell. C) decreases glucose transport into the cell by decreasing its concentration gradient across the plasma membrane. D) converts glucose into a form that can more easily be exported from the cell. E) maintains a higher level of glucose outside the cell.
A
Predict which of the following lipid characteristics would be most important to form the best liposomes for delivering a drug into a cell? A) It is amphipathic. B) It contains a carbon ring structure similar to that in cholesterol. C) It is short and polar like glycerol. D) It is linked to mannose E) It has three fatty acid chains like a triglyceride.
A
You are investigating the structure of the seeds of a newly discovered tropical plant. There is storage material inside the seed. You treat the seed with peptidase (an enzyme that breaks peptide bonds), glycoside hydrolases (an enzyme that breaks β glycosidic bonds), and amylase (an enzyme that breaks α glycosidic bonds). Only the amylase appears to dissolve the storage material in the seed. What does this tell you about the identity of the storage material? A) The seed contains starch to store carbon and energy. B) The seed contains lipids to store carbon and energy. C) The seed contains fibrous proteins to store carbon and energy. D) The seed contains cellulose to store carbon and energy. E) The seed contains globular proteins to store carbon and energy.
A
You are studying the response of macrophages infected with the intracellular bacterium Brucella, specifically by examining which gene products are being expressed. You would be studying the macrophage ________ to obtain this information. A) transciptome B) proteome C) genome D) amplicon E) metabolome
A
You are working on a project that involves the direct observation of DNA molecules. The microscope that would give you the best information at this time would be the A) transmission electron microscope. B) light microscope. C) phase-contrast microscope. D) fluorescent microscope. E) digital video microscope.
A
_______ improved the original light microscope in the late 1600s, allowing the visualization of ________. A) Antonie van Leeuwenhoek; sperm cells, bacteria, algae, and other protists B) Theodor Schwann; the internal structures of cells, such as ribosomes, nuclei, and golgi bodies C) Robert Brown; cell structures using fluorescent antibodies D) Rudolf Virchow; collagen and muscle cells E) Robert Hooke; bacteria and viruses
A
1 mm = ________ nm 25) A) 10 B) 1,000,000 C) 1/1000 D) 1/1,000,000 E) 1000
B
All of the following are true about a partition coefficient except? A) it is the ratio of solubility in an organic solvent to solubility in water. B) it is the concentration at which the rate of transport is half maximal. C) it depends on the polarity of the molecule. D) it can be used to predict the probability that an amino acid is part of a transmembrane region of a protein. E) it is high for a molecule that readily crosses membranes by simple diffusion.
B
Bioenergetics can be simply defined as? A) the application of biological principles to physics. B) applied thermodynamics. C) holding constant the variables in the universe. D) a subdivision of biology. E) the units in which energy is expressed.
B
Cholesterol? A) is found in abundance in prokaryotic cell membranes. B) buffers membrane fluidity by increasing fluidity at low temperature and decreasing fluidity at high temperature. C) increases permeability for small polar molecules. D) increases permeability for Ca2+. E) All of the above are correct.
B
Disulfide bonds are often found to stabilize which of the following levels of protein structure? A) secondary B) tertiary C) primary, secondary, and tertiary D) primary E) None of these structures involve disulfide bonds.
B
Each of the following is true about homeoviscous adaptation in membranes except? A) maintains membrane viscosity despite changes in environmental temperature. B) occurs primarily in homeothermic (warm-blooded) organisms and only rarely in poikilothermic (cold-blooded) organisms. C) may decrease the average length of membrane lipid fatty acid tails. D) may increase the proportion of cholesterol in animal cell membranes. E) may increase the unsaturation of membrane lipid fatty acid tails.
B
In a chemical reaction, the standard free energy change (ΔG°') is calculated to be 3.67 cal/mol. What can be said of the chemical reaction? A) Products predominate over reactants at equilibrium under standard conditions. B) The reaction is not spontaneous under standard conditions. C) The reaction is at equilibrium under standard conditions. D) The reaction goes spontaneously to the right under standard conditions. E) There can be no reaction.
B
In carrier protein function kinetics, Km is the? A) maximal rate of solute transport. B) solute concentration at which the transport rate is half maximal. C) standard free energy change used to calculate the maximal rate of transport. D) constant rate of transport regardless of concentration gradient. E) initial rate of transport at any concentration.
B
Life is possible because living cells maintain themselves in a steady state, with most of their reactions? A) conserving energy and matter. B) far from thermodynamic equilibrium. C) near thermodynamic equilibrium. D) conserving matter. E) conserving energy.
B
Matter and energy flow through the biosphere. The flow of matter, however, differs from the flow of energy. Which of the following statements accurately describes these differences? A) Matter and energy flow sometimes in cycles and sometimes unidirectionally. B) Matter flows in cycles, whereas energy flows in one direction. C) Energy flows from chemotrophs to phototrophs, whereas matter flows from phototrophs to chemotrophs. D) Energy flows as organic molecules are reduced to inorganic molecules, but matter does not. E) Matter does not accompany energy as it enters the biosphere, but it does flow with energy from the biosphere.
B
Melvin Calvin and his colleagues used which of the following to deduce the steps in the Calvin cycle? A) ultracentrifugation B) radioisotopes C) Drosophila melanogaster D) negative staining E) electron microscopy
B
Most cells have a negative plasma membrane potential (Vm) because they have? A) an excess of positively charged solute molecules inside the cell. B) an excess of negatively charged solute molecules inside the cell. C) equal concentrations of ions on both sides of the membrane. D) an excess of water molecules inside the cell. E) an excess of negatively charged solute molecules outside the cell.
B
Scientists use various terms to describe conclusions reached through the scientific method. Which of the following terms conveys the least degree of certainty? A) law B) hypothesis C) theory D) both hypothesis and theory E) both theory and law
B
Starting with shredded spinach leaves, you follow a procedure that separates cellular organelles into different fractions. To identify the fraction that contains the mitochondria, you should test for the presence of? A) aquaporin. B) electron transport proteins. C) phospholipids present only in the mitochondrial outer membrane. D) insulin receptors. E) mitochondrial wall polysaccharides.
B
The Latin phrase omnis cellula e cellula refers to a cellular principle. Which of the following statements is the best interpretation of this phrase? A) Cells generally are found in clusters. B) All cells arise only from preexisting cells. C) Tissues are composed of similar cells. D) The cell is the basic unit of structure. E) Organs are composed of tissues and cells.
B
The graph below shows the concentrations of B and C inside the cell over time when the cell that has imported B and C in Figure 8.1 above is transferred to a solution containing a much lower concentration of B and C. Based on these data and coupled with the data observed above, substance C is transported via? A) facilitated transport. B) active transport. C) passive transport. D) simple diffusion. E) A, B, and C.
B
The number and location of transmembrane segments in an integral membrane protein can be inferred from the amino acid sequence of the protein by a computer-generated? A) Western blot. B) hydropathy plot. C) DNA sequence. D) prediction of glycosylation sites. E) freeze-fracture replica.
B
The steady state vital to life is possible because? A) all reactions are exothermic. B) the cell continually takes up energy from the environment. C) all cells are autotrophic. D) the cell cannot convert energy from one form to another. E) all reactions are at equilibrium.
B
The steps of the scientific method, in the correct order, are? A) collect data, interpret results, test the hypothesis, make observations, and design experiments. B) make observations, formulate the hypothesis, design experiments, collect data, interpret results, and draw conclusions. C) design experiments, draw conclusions, collect data, interpret results, make observations, and test the hypothesis. D) collect data, interpret results, test the hypothesis, design experiments, make observations, and draw conclusions. E) none of the above.
B
The two strands of DNA are held together by ________; thus ________. A) covalent bonds; double-stranded DNA is very stable at a range of temperatures B) hydrogen bonds; double-stranded DNA separates into two separate strands at high temperatures C) ionic bonds; double-stranded DNA separates into two separate strands in water D) antiparallel bonds; double-stranded DNA is amphipathic E) hydrophobic interactions; double-stranded DNA separates into two separate strands when dissolved in a hydrocarbon (hydrophobic) solvent.
B
Using a laser beam to inactivate fluorescence dye molecules connected to proteins or lipids on a cell membrane is called? A) liposome formation. B) photobleaching. C) electrophoresis. D) freeze-fracturing. E) affinity labeling.
B
What is the ∆G for the inward transport of sucrose? A) +1.774 kcal/mol; an exergonic reaction B) +1.774 kcal/mol; an endergonic reaction C) −1.774 kcal/mol; an exergonic reaction D) −1.774 kcal/mol; an endergonic reaction E) None of the above are correct.
B
What specific type of P-type ATPase pumps H+ to acidify the stomach and is inhibited by proton 30) pump inhibitor drugs used to treat excess stomach acid? A) type 1 B) type 2 C) type 3 D) type 4 E) type 5
B
What would be the net ∆G for the coupling of these two reactions? A) −1.774 kcal/mol B) −3.459 kcal/mol C) +7.007 kcal/mol D) −7.007 kcal/mol E) +3.459 kcal/mol
B
When a mouse cell and a human cell with different cell-surface protein markers are fused using polyethylene glycol (PEG) and immediately placed at 0°C, what would you expect happens to the mouse and human marker proteins? A) Only the mouse cell marker proteins will disperse throughout the fused membrane; the human marker proteins will remain confined to the original human region of the fused membrane. B) The mouse and human markers will migrate little and remain confined to their original membrane regions. C) The mouse and human markers will migrate to opposite poles of the fused membrane. D) Both the mouse and human marker proteins will rapidly disperse evenly throughout the fused membrane. E) Both mouse and human markers will be endocytosed by the fused cell and destroyed in the fused cell.
B
When examining an electron micrograph of cells obtained from a new deep-sea life-form, you 8) notice that the plasma membranes appear as two dark lines separated by a lightly stained region. Which of the following investigator(s) used a similar observation as the basis for a model of membrane structure? A) Overton B) Robertson C) Singer and Nicolson D) Unwin and Henderson E) Gorter and Grendel
B
Whereas animal cells drive indirect transport with a Na+ gradient, most other organisms use? A) a Ca2+ gradient. B) an H+ gradient. C) a glucose gradient. D) light energy. E) osmosis.
B
Which of the following accurately describes the structure of fibrous proteins? A) Fibrous proteins are composed of an equal mixture of α helices and β sheets with interconnecting looped segments. B) Fibrous proteins are usually composed of either α helices or β sheets throughout the molecule, giving them a highly ordered, repetitive structure. C) Fibrous proteins have a simple primary structure and very little secondary structure, resulting in long, thin fibers. D) Fibrous proteins usually contain a number of different domains with different structural motifs. E) Fibrous proteins have an extensive tertiary and quaternary structure that affects the strength and elasticity of each fiber.
B
Which of the following contributes to the stability of the DNA double helix? A) hydrogen bonding between the phosphate and sugar groups in the backbone of the double helix B) hydrophobic interactions between aromatic bases at the center of the double helix C) ionic bonds between the negatively charged phosphate groups and the positively charged pyrimidine bases. D) covalent bonding between complementary purine and pyrimidine bases. E) hydrophobic interactions between aromatic bases at the center of the double helix and ionic bonds between the negatively charged phosphate groups and the positively charged pyrimidine bases
B
Which of the following is a chemoheterotroph? A) a photosynthetic bacterium B) a mushroom C) a tree D) algae E) grass
B
Which of the following is a phototroph? A) an earthworm B) a tree C) a person D) a mushroom E) soil bacterium
B
Which of the following is found exclusively in RNA? A) thymine B) uracil C) adenine D) cytosine E) guanine
B
Which of the following types of organisms contain sphingomyelin in cell membranes? A) algae B) animals C) plants D) prokaryotes E) yeast
B
Which of the following types of protein would be most easily removed from a membrane by changing pH or ionic strength? A) glycosylated integral protein B) peripheral protein C) fatty acid-anchored protein D) integral protein E) GPI-anchored protein
B
Wöhler revolutionized biology through his demonstration that biological molecules are governed by the ordinary laws of physics and chemistry. He demonstrated this principle by? A) defining the laws of heredity. B) synthesizing urea in the laboratory from ammonium cyanate. C) inventing mass spectrometry which is commonly used to determine the size and composition of individual proteins. D) developing techniques for isolating, purifying, and analyzing subcomponents of cells. E) discovering active agents in cell extracts that were specific biological catalysts that have since come to be called enzymes.
B
You wish to obtain a purified sample of mitochondria from lysed cells. The best way to obtain this sample would be? A) both centrifugation and polyacrylamide gel electrophoresis. B) centrifugation. C) chromatography. D) polyacrylamide gel electrophoresis. E) agarose gel electrophoresis.
B
The chemical nature of each amino acid is determined by which of the following groups? A) hydrogen B) amino C) R D) carboxyl E) hydroxyl
C
Different ABC transporters can transport A) sugars? B) polysaccharides. C) ions. D) amino acids and peptides. E) All of the above are correct.
E
"The total amount of mass-energy in the universe is constant," is a statement of? A) enthalpy. B) the second law of thermodynamics. C) the first law of thermodynamics. D) entropy. E) thermodynamic spontaneity.
C
Consider an erythrocyte with an internal glucose concentration of 0.1 mM and an external glucose concentration of 5 mM. Each of the following is true about GLUT1 transport of glucose across the plasma membrane into the cell except? A) ΔG° is always equal to 0. B) Keq is always equal to 1. C) ΔG depends on the concentration gradient. D) inward movement is exergonic. E) the rate of GLUT1 transport is faster than that of simple diffusion.
C
Each of the following molecules move across membranes by simple diffusion except? A) carbon dioxide. B) oxygen. C) glucose. D) fatty acids. E) water.
C
Energy is important to life forms because? A) all life forms require a continuous supply of energy and energy is required to do work. B) energy is required to do work. C) all life forms require a continuous supply of energy, energy is required to do work, and energy is required to make specific alterations in the cell. D) energy is required to make specific alterations in the cell. E) all life forms require a continuous supply of energy.
C
Gated ion channels include each of the following except? A) ligand-gated channels. B) voltage-gated channels. C) patch clamp-gated channels. D) mechanosensitive channels. E) All of the above are types of gated channels.
C
In response to temperature changes, cell membranes change state to become more solid or more fluid by undergoing? A) membrane folding. B) transverse diffusion. C) a phase transition. D) differential scanning calorimetry. E) lipid raft formation.
C
Jacques Monod and François Jacob deduced the mechanism responsible for the regulation of prokaryotic gene expression. They are, therefore, responsible for launching the era of? A) biochemistry. B) the scientific method. C) molecular genetics. D) light microscopy. E) radioisotopes.
C
Nerve impulses travel along neurons by the opening of channels that allow sodium ions to flow inward, followed by an outward flow of potassium ions. In order to ensure that the impulse may be produced at any time, sodium is actively transported out of the cell and potassium is transported into the cell by the sodium/potassium pump. Which of the following types of work is performed by the sodium/potassium pump? A) synthetic B) mechanical C) concentration D) bioluminescent E) electrical
C
Robert Hooke coined the term cell when studying thin slices of cork. These ________ were the first cells observed because ________. A) "little rooms"; they were 100 nm in diameter, much larger than most plant cells B) dead animal cells; they were immobile and did not need to be fixed before viewing C) dead plant cells; the thick cells walls did not require high resolution or magnification to view D) compartments; they were actually the result of multiple cells that had merged and died to form large compartments that were easy to view E) immune cells; they produce antibodies that embed in the cell membrane to make it visible
C
The most common number of carbons in fatty acid hydrocarbon chains of membrane phospholipids is? A) 7. B) 10. C) 16. D) 19. E.24
C
The most prominent lipids in animal cell membranes are? A) glycolipids. B) cerebrosides. C) phospholipids. D) cholesterol. E) phytosterol.
C
The nucleoside triphosphate molecules in DNA are linked together in the 5'→3' by a(n) ________ bridge. A) peptide B) covalent C) phosphodiester D) phosphate E) phosphatidyl
C
The primary difference between active transport and facilitated diffusion is that active transport is the only one of the two in which? A) the direction of transport is [S]high → [S]low. B) transporter proteins are required. C) the direction of transport is [S]low → [S]high. D) the mechanism is not saturable. E) the S concentration gradient provides the energy necessary for S transport.
C
Two proteins associated with a rare neurodegenerative disorder have been sequenced. Protein A contains many polar amino acids with small regions containing nonpolar, hydrophobic amino acids. Protein B is rich in nonpolar, hydrophobic amino acids with only two small regions containing polar amino acids. What might this suggest about the two proteins? A) Protein A and Protein B are complementary parts of a supramolecular structure. B) Protein A is fibrous and Protein B is globular. C) Protein A may be a cytoplasmic protein and Protein B may be a membrane associate protein. D) The two proteins may have different secondary structures. E) Protein A is most likely and enzyme and Protein B is most likely a storage protein.
C
Under the conditions of a given reaction, a positive ΔG' means? A) the reaction is at equilibrium. B) work can be done. C) the reaction will not occur. D) no energy needs to be added. E) the reaction is spontaneous.
C
What are the three general types of amino acids? A) positive, negative, and noncharged B) acidic, basic, and neutral C) hydrophobic, polar (noncharged), polar (charged) D) covalent, noncovalent, and van der Waals forces E) α helices, β sheets, and looped segments
C
What is the ∆G for the inward transport of sodium ions? A) +5.233 kcal/mol; an exergonic reaction B) −5.233 kcal/mol; an endergonic reaction C) −5.233 kcal/mol; an exergonic reaction D) +5.233 kcal/mol; an endergonic reaction E) None of the above are correct.
C
When the ΔG°' of a chemical reaction is positive (K'eq < 1.0) under standard conditions? A) the reaction is exothermic. B) the reaction is spontaneous to the right. C) reactants predominate over products. D) work can be done under these conditions. E) reactants and products are at equilibrium.
C
Which of the following can only be viewed by electron microscopy? A) nuclei B) prokaryotes C) DNA D) mitochondria E) frog eggs
C
Which of the following glucose transporters has properties that facilitate glucose transport out of human liver cells to maintain blood sugar level homeostasis? A) GLUT1 B) GLUT3 C) GLUT2 D) GLUT5 E) GLUT4
C
Which of the following is a terpene? A) chitin B) estrogen C) vitamin A D) glycerol E) testosterone
C
Which of the following is true of a nanometer? A) A nanometer is one millionth of a meter. B) The nanometer is the most common measurement used in measuring whole cells. C) A nanometer is equivalent to 10 Angstroms (Å). D) A nanometer is about the size of a common bacterial cell. E) None of the above.
C
You are researching a cytoplasmic protein associated with a nerve disorder. The native form of the enzyme appears to be globular protein; however, when a sample of the purified protein is treated with a chemical that reduces disulfide bonds, the enzymatic activity decreases dramatically and multiple globular proteins can be detected in the sample. What does this tell you about the protein? A) The protein is most likely composed of α helices that are held together by disulfide bonds. B) The protein is most likely composed of β sheets that are held together by disulfide bonds. C) The protein is most likely composed of multiple polypeptide chains that are held together by disulfide bonds. D) The primary and secondary structure of the protein depends on disulfide bonds. E) The primary structure of the protein contains multiple cysteine residues that are hydrolyzed by the chemical reductant.
C
A general trend in the structure of many biomolecules is? A) that each class of biomolecule can form either fibrous or globular conformations depending on the chemical conditions inside the cell. B) that four different monomers form the basis for the functional and structural properties of each polymer. C) that each class of biomolecule forms one type of secondary structure independent of the order of the monomers in the polymer. D) that the order and bonding of monomers form the basis for the secondary and tertiary structure of the polymer. E) that they are all soluble in water independent of the size of the polymer.
D
ABC-type ATPases that inhibit the effectiveness of antitumor drugs by transporting the drugs out of tumor cells are known as? A) Na+-drug antiporters. B) the cystic fibrosis transmembrane conductance regulator (CFTR). C) porins. D) multidrug resistance (MDR) transporters. E) None of the above; no such transporter has been identified in eukaryotes.
D
Binding and hydrolysis of ATP in a "cassette" domain is part of the transport mechanism of which of the following types of transporters? A) V type B) type C) P type D) ABC type E) All of the above are correct.
D
Bioluminescence can be driven by? A) mushrooms. B) green fluorescent protein. C) ATP. D) either ATP or chemical oxidation. E) chemical oxidation.
D
Cell biology emerged from which of the following fields of biology? A) cytology and biochemistry B) genetics C) biochemistry D) biochemistry, cytology, and genetics E) cytology
D
Cellulose belongs to which of the following groups of macromolecules? A) nucleic acids B) lipids C) proteins D) carbohydrates E) none of these
D
Cholesterol is a ________, which ________. A) fatty acid; functions in energy storage B) steroid; is the basis for many animal and plant hormones C) steroid; is a component of eukaryotic membranes D) steroid; is a component of eukaryotic membranes and is the basis for many animal and plant hormones E) terpene; is the basis for many animal and plant vitamins
D
Consider a nerve cell with an internal Cl- concentration of 50 mM, a membrane potential of 60 mV and an external Cl- concentration of 100 mM. Each of the following is true for Cl- import into the cell except? A) import requires energy input. B) import is down a concentration gradient. C) import ΔG is positive. D) import is down an electrochemical concentration gradient. E) All are true.
D
E. coli uses which of the following enzymes to regulate membrane fluidity? A) fatty acid convertase B) glucose-6-phosphatase C) kinase D) desaturase E) gangliosidase
D
Each of the following is a function of membranes except? A) sites for specific biochemical functions. B) regulation of transport. C) information storage. D) celL-cell communication. E) defining cell and organelle boundaries.
D
Each of the following is an example of facilitated diffusion except? A) glucose transport by GLUT1. B) aquaporin transport. C) ion channel transport. D) oxygen transport. E) chloride-bicarbonate exchange.
D
Each of the following is true for the mechanism of the Na+/K+ ATPase pump except? A) Each E1-E2 cycle pumps 3 Na+ ions out and 2 K+ ions in. B) the E2 conformation is open to the outside of the cell and has high affinity for K+. C) Na+ triggered phosphorylation of the pump stabilizes the E2 conformation. D) K+ triggered dephosphorylation of the pump stabilizes the E2 conformation. E) the E1 conformation is open to the inside of the cell and has high affinity for Na+.
D
Fireflies have the ability to convert the energy in ATP to light. Which of the following types of work is performed by the firefly? A) concentration B) mechanical C) electrical D) bioluminescent E) heat
D
Frog oocytes are a useful experimental system for studying transporters, because frog oocytes possess all of the following characteristics except? A) they are relatively inexpensive and easy to obtain. B) they can be maintained in little more than pure water. C) they are large, easily injected cells. D) they express all transporters known. E) they express injected heterologous mRNAs.
D
Gregor Mendel was most influential in which field of biology? A) prokaryotic transformation B) chromatography C) cytology D) genetics E) biochemistry
D
The classic work of Friedrich Wöhler (1828) that united the fields of biology and chemistry was based on the? A) identification of nucleotide bases. B) discovery of ATP. C) discovery of yeast ferments. D) production of urea in the laboratory. E) analysis of gene segregation.
D
The components of a nucleotide are? A) a six-carbon sugar, an ester linkage, and a four-ringed hydrocarbon. B) a carboxyl group, an amine group, and a variable R group. C) two six-carbon sugars attached with an α(1→4) glycosidic bond. D) a five-carbon sugar, a phosphate group, and a nitrogen-containing aromatic base. E) a three-carbon alcohol with a hydroxyl group on each carbon and three fatty acids.
D
The energy necessary to drive the bacteriorhodopsin proton pump that creates the proton gradient needed for ATP synthesis is generated by? A) a H+ concentration gradient across the membrane. B) ATP hydrolysis by ATP synthase. C) a membrane potential of 100 mV across the membrane. D) retinal absorption of light energy. E) a Na+ electrochemical gradient across the membrane.
D
The function of triglycerides is? A) store information. B) to form semipermeable membranes. C) to transport substances in and out of cells. D) to store energy. E) Both B and C are correct.
D
The outcome of the joining of cytology and biochemistry yielded a better understanding of the cell by? A) creating bioinformatics. B) identification of cellular structures. C) identification of biochemical pathways and creating bioinformatics. D) identification of cellular structures and biochemical pathways. E) identification of cellular biochemical pathways.
D
Which of the following biochemical techniques uses an electrical field to separate macromolecules based on their mobility through a semisolid gel? A) ultracentrifugation. B) mass spectrometry. C) light microscopy. D) electrophoresis. E) chromatography.
D
Which of the following has the greatest number of glycosidic bonds? A) triacylglycerol B) amylose C) glucose D) DNA E) vitamin A
D
Which of the following is a possible function of a terpene? A) cell surface receptor B) motility C) enzyme D) vitamin E) structure
D
Which of the following is true for the mechanism of the 2Na+/glucose symporter? 38) A) Binding of 2 Na+ to the symporter open to the outside of the cell allows a glucose molecule outside the cell to bind. B) Release of 2 Na+ ions to the inside of the cells causes release of the glucose molecule. C) Binding of Na+ and glucose causes the symporter to open to the inside of the cell. D) Binding of 2 Na+ to the symporter on the inside of the cell causes the symporter to open to the outside of the cell and release of the Na+ ions. E) All of the above are steps in the mechanism.
D
Which of the following is true of glycolipids? A) Fructose and sucrose are often part of glycolipids. B) Glycolipids are found in plastids and are used to store energy. C) Usually more than 10 sugar units are attached to the glycolipid. D) Glycolipids are usually found on the exterior surface of the plasma membrane. E) Glycolipids contain steroids.
D
Which of the following is true of purines? A) Both adenine and thymine are purines. B) Cytosine is a purine. C) Purines bind readily to deoxyribose but not to ribose. D) Purines have a double-ringed structure. E) Adenine's bonding to thymine is stronger than is guanine's to cytosine.
D
Which of the following lipids would you expect to find associated with chloroplast membranes? A) galactocerebroside B) hopanoids C) phosphatidylserine D)monogalactosyldiacylglycerol E) glycosphingolipid
D
Which of the following molecules enters kidney cells via a specific transporter? A) oxygen B) cholesterol C) ethanol D) water E) carbon dioxide gas
D
Which of the following proposed the "sandwich" model of membranes, in which lipid bilayers are coated on both sides with thin sheets of proteins? A) Robertson B) Gorter and Grendel C) Langmuir D) Davson and Danielli E) Overton
D
Which of the following statements is false? A) There are more than 60 different kinds of amino acids present in cells. B) Only around 20 amino acids are used in protein synthesis. C) An amino acid has an N-terminus, a C-terminus, and an R group. D) Equal amounts of D- and L-amino acids are found in cells. E) The R group of amino acids differs from one amino acid to another.
D
Which of the following would be the most thermodynamically unfavorable membrane lipid activity in a membrane? A) association with a neighboring lipid B) association with cholesterol C) lateral diffusion D) transverse diffusion E) rotation
D
Which process involves an increase in entropy of the system? A) any spontaneous process B) synthesis of cellulose C) freezing of ice D) combustion of paper E) formation of raindrops
D
Which type of P-type ATPase would you expect to find is defective in a novel cell line in which 31) you observe that maintenance of the phospholipid asymmetry in the plasma membrane is impaired? A) type 1 B) type 2 C) type 3 D) type 4 E) type 5
D
Based on the same graph, transport of substances B and C? A) is not directly dependent on the B and C permeability coefficients. B) is likely faster than simple diffusion. C) exhibits saturation kinetics. D) involves transporter proteins. E) All of the above are correct.
E
32) The Na+/K+ ATPase pump actively moves A) 1 Na+ out, 1 K+ in. B) 2 Na+ out, 3 K+ in. C) 2 Na+ in, 3 K+ out. D) 3 Na+ in 2 K+ out. E) 3 Na+ out, 2 K+ in.
E
5) Which of the following protein types would you predict is defective in kidney water balance disorders? A) anion exchange protein B) porin C) class ATPase D) GLUT E) aquaporin
E
A colleague gives you two tubes containing membrane fractions from an animal cell lysate. One tube contains the plasma membrane fraction, and the other tube contains the mitochondrial inner membrane fraction, but the tubes are not labeled. When you analyze the macromolecule composition of the samples, you are confident that the second tube contains the mitochondrial fraction, because the sample has? A) a higher ratio of cholesterol to phospholipids. B) more carbohydrate in glycoproteins. C) a lower protein to lipid ratio. D) more GPI-anchored proteins. E) a higher protein to lipid ratio.
E
A scientist is examining motile protist. He wishes to determine their direction of movement. Which of the following microscopic techniques is least likely to be used to view these cells? A) differential interference contrast microscopy B) phase-contrast microscopy C) fluorescence microscopy D) light microscopy E) electron microscopy
E
Active transport makes it possible for cells to? A) maintain nonequilibrium intracellular concentrations of ions such as Na+, K+, Ca2+, and H+. B) establish an electrical potential across the membrane. C) transport out secretory products and waste material against concentration gradients. D) take up nutrients from the environment against concentrations gradients. E) All of the above are correct.
E
Although all P-type ATPases use the energy of ATP hydrolysis to transport solutes they differ in which of the following? A) structure B) mechanism C) physiological roles D) localization in cells E) All of the above are correct.
E
Cystic fibrosis is the result of a malfunction of a cellular ABC transporter that transports? A) amino acids. B) glucose. C) vitamin B12. D) a hydrophobic drug. E) Cl−.
E
Each of the following is a characteristic of active transport mechanisms except? A) coupling a thermodynamically unfavorable (endergonic) process with a favorable (exergonic) process. B) sensitivity to inhibitors such as proton pump inhibitors. C) moving solutes away from equilibrium across a membrane. D) coupling transport of a solute down its concentration with transport of another solute up its concentration gradient via a symport or antiport mechanism.. E) nondirectionality for moving a solute in either direction across a membrane depending on the solute concentration gradient.
E
Each of the following is a type of cellcell junctions except A) tight. B) gap. C) plasmodesmata. D) adhesive. E) All are cell-cell junctions.
E
Early microscopes did not allow clear visualization of cells because they were limited by A) refraction. B) resolution. C) number of kernels. D) magnification. E) both magnification and resolution.
E
FRAP has revealed that some proteins move in cell membranes much slower than they move in reconstituted liposomes. Which of the following could account for limited mobility of proteins in cell plasma membranes? A) anchorage to the extracellular matrix. B) anchorage to the cell cytoskeleton. C) association with other proteins in a large complex. D) association with lipid rafts. E) All could limit protein mobility.
E
Fatty acids are ________; they function in the cell as ________. 18) A) short chains of double-bonded carbon molecules; vitamins, cofactors, and storage lipids B) short chains of double-bonded carbon molecules; vitamins and cofactors C) four-ringed hydrocarbon molecules; key components of membranes D) short chains of double-bonded carbon molecules; storage lipids E) long, unbranched hydrocarbon chains with a carboxyl group at one end; building blocks for other lipids
E
Hydrogen bonding is most important in stabilizing the ________ structure of many proteins. A) quaternary B) primary, secondary, tertiary, and quaternary C) tertiary D) primary E) secondary
E
In a biochemical reaction, reactants may be converted into products. The extent to which this occurs spontaneously is expressed as which of the following? A) Keq B) TΔS C) ΔS D) temperature E) ΔG
E
In studying osteoporosis in humans, you wish to test a newly designed treatment for efficacy. Your best choice for a model organism would be? A) Escherichia coli. B) Pisum sativum. C) Caenorhabditis elegans. D) Arabidopsis thaliana. E) Mus musculus.
E
Ion gradients established across membranes by V-type ATPase pumps range from? A) 10-100-fold B) 1-10-fold C) 10-1000-fold D) 1-1000-fold E) 10-10,000-fold
E
Lipid rafts are associated with which of the following activities? A) responding to extracellular signals B) transport of cholera toxin into cells C) transport of nutrients across cell membranes D) immune responses E) All of the above are correct.
E
Localized regions of plasma membranes that contain cholesterol and proteins involved in cell signaling are known as? A) cadherin junctions. B) plasmodesmata. C) arterial plaques. D) gap junctions. E) lipid rafts.
E
Muscle contraction is an example of which of the following types of work? A) electrical B) bioluminescent C) concentration D) heat E) mechanical
E
Oxidation? A) is rare in biological reactions. B) involves the removal of oxygen atoms from a molecule. C) occurs when an atom accepts electrons. D) is endothermic. E) occurs when oxygen atoms are added to a molecule and energy released.
E
Photosynthesis is an important process that? A) is performed by heterotrophs. B) only plants can perform. C) is performed by organisms living near deep-ocean thermal vents. D) produces oxidized products. E) uses water and carbon dioxide as reactants.
E
Proline is referred to as the "helix breaker" because? A) it has a polar functional group. B) its only found in the L form, which is incompatible with helical protein structure. C) it lacks a charged functional groups for ionic bonding. D) it is hydrophobic. E) it lacks the hydrogen atom needed for hydrogen bonding.
E
The composition of lipids in the outer and inner monolayers of cell membrane lipid bilayers is? A) the same for all cell plasma membranes but different from the composition in mitochondrial and chloroplast membranes. B) identical in each monolayer. C) highly random for each monolayer. D) twice as concentrated in the inner monolayer as in the outer monolayer. E) asymmetrical; i.e., different in each monolayer.
E
The flow of energy in the biosphere begins primarily with A) lightning. B) oxidized chemicals. C) chemotrophs. D) high-energy electrons. E) phototrophs.
E
The limit of resolution can best be defined as A) the magnification power of a microscope. B) the inverse of the wavelength of light; it is greatest for black light. C) the solvent that must be available to remix a solution. D) the distance that an object must be moved to be distinguished from its background. E) the distance that two objects must be apart to be distinguished as separate objects.
E
The primary structure of a protein? A) is the linear sequence of amino acids that are linked together by peptide bonds. B) is important both genetically and structurally. C) is important for determining the secondary and tertiary structure of a protein. D) is simply the order of amino acids from one end of the protein to another. E) All of these statements are true.
E
Which of the following is a characteristic of facilitated diffusion (passive transport) of a molecule across a membrane? A) It is highly specific for the molecule being transported. B) Its rate is higher than that of simple diffusion of the molecule. C) The rate of transport is saturable. D) The direction of transport is determined by concentration and/or electrochemical gradients. E) All of the above are true.
E
Which of the following is an endothermic process? A) oxidation of metals B) adding a strong acid directly to water C) combustion reactions D) neutralization reactions of the addition of strong acid directly to a strong base E) ice melting
E
Which of the following is closest to a micrometer in size? A) the width of a strand of DNA B) the length of a chicken egg C) the size of a ribosome D) the length of a plant cell E) a typical prokaryotic cell
E
Which of the following is false? A) Phospholipids are amphipathic. B) Phospholipids are important in membrane structure. C) Phosphatidic acid contains two fatty acids and a phosphate group. D) Sphingolipids are the predominant phospholipid in membranes. E) Serine is a molecule that may be part of a phosphoglyceride.
E
Which of the following is not a polymer of numerous monomer units? A) an RNA molecule B) cellulose C) starch D) a polypeptide E) a phospholipid
E
Which of the following is true about glycosylated plasma membrane proteins? A) Carbohydrate is added only after the protein is in the plasma membrane. B) Only one specific site is glycosylated on each protein. C) The carbohydrate usually is one sugar and rarely more than 5 sugars long. D) N-linked carbohydrates are linked to hydroxyl groups in protein R groups. E) The carbohydrates can be detected experimentally with ferretin-linked lectins.
E
Which of the following pairs correctly matches the monomer with its polymer? A) peptides; proteins B) glucose; proteins C) amino acids; polysaccharides D) terpenes; nucleic acids E) nucleotides; nucleic acids
E
Which of the following statements are false concerning phototrophs? A) They can be bacteria. B) They capture light energy. C) They provide energy for chemotrophs. D) They store energy as glucose. E) They are not autotrophs.
E
Which of the following statements is true? A) Unsaturated fatty acids are usually branched. B) Fatty acids with 24 carbons are most common. C) Fatty acids are synthesized by the stepwise addition of three carbon units. D) Hormones are unsaturated fatty acids. E) Saturated fatty acids have no double bonds between carbons.
E
Which of the following types of transport occur across the erythrocyte membrane? A) Cl− bicarbonate ion antiport B) glucose uniport C) aquaporin water transport D) O2 and CO2 passive diffusion E) All of the above are correct.
E
Which organelle stores most of the DNA in plant and animal cells? A) lysosome B) mitochondrion C) Golgi complex D) chloroplast E) nucleus
E
Which type of microscopy has the greatest resolving power? A) fluorescence microscopy B) confocal scanning microscopy C) phase-contrast microscopy D) digital video microscopy E) electron microscopy
E