The biochemical property of lectins that is the basis for most of their biological effects is their ability to bind to:
A: specific ligands B: specific oligosaccharides C: specific peptides D: specific DNA
B: specific oligosaccharides
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4
Which statement about glycoconjugates is false?
A: The glycosaminoglycan chain of the proteoglycan can bind to extracellular proteins though electrostatic interactions B: Glycolipids are found in specific organelles, such as golgi complexes C: glycosphingolipids play a role in signal transduction
B: Glycolipids are found in specific organelles, such as golgi complexes
A: RNA can never be double-stranded; therefore, DNA is more stable B: thymine forms more stable hydrogen bonds than uracil C: The 2' hydroxyl groups in RNA (absent in DNA) are directly involved in the hydrolysis of oligonucleotides
C: The 2' hydroxyl groups in RNA (absent in DNA) are directly involved in the hydrolysis of oligonucleotides
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8
In a sample of DNA isolated from an unidentified species of bacteria, adenine makes up 28% of the total bases. Which statement is false about the relative proportions of the bases in the DNA sample?
A: A and T bases account for 56% of the bases B: The DNA must contain 28% C C: C, T, and G bases account for 72% of the bases
B: The DNA must contain 28% C
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9
Which statement regarding bases in DNA is false?
A: They absorb UV light B: Pyrimidines are aromatic; purines are not C: They have vertical stacking interactions D: They hydrogen bond between two or more complementary DNA strands
B: Pyrimidines are aromatic; purines are not
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10
Which of the following is NOT associated with DNA structure?
A: G tetraplexes B: three hydrogen bonds between A and T C: pyrimidines in the anti conformation
B: three hydrogen bonds between A and T
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11
Which statement regarding mRNA is false?
A: It is always monocistronic B: It carries genetic information to the ribosomes C: It is formed by transcription
A: It is always monocistronic
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12
In glycoproteins, the carbohydrate moiety is always attached through the amino acid residues:
A: asparagine, serine, or threonine B: aspartate or glutamate C: glutamine or arginine D: glycine, alanine, or aspartate E: tryptophan, aspartate, or cystein
A: asparagine, serine, or threonine
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13
Which characteristic is NOT one that is true of glycosaminoglycans?
A: found in extracellular matrix B: always contain sulfates C: are heteropolysaccharides D: are disaccharide repeat units
B: always contain sulfates
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14
Which of the following characteristics is most likely true about the glycosaminoglycan hyaluronan?
A: is a homopolysaccharide B: consists of alternating residues of D-glucuronic acid and N-acetylglycosamine C: is covalently linked to specific proteins D: is a much shorter polymer than heparin
B: consists of alternating residues of D-glucuronic acid and N-acetylglycosamine
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15
Which of the following characteristics is most likely true about the phosphodiester bond that link adjacent nucleotides in both RNA and DNA?
A: always link A with T and G with C B: are susceptible to alkaline hydrolysis C: are uncharged at neutral pH D: form between the planar rings of adjacent bases E: join the 3' hydroxyl of one nucleotide to the 5' hydroxyl of the next
E: join the 3' hydroxyl of one nucleotide to the 5' hydroxyl of the next
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16
Which of the following is most likely true about a strand of DNA or RNA?
A: contains 5'-2' phosphodiester bonds B: might be an oligonucleotide C: has a C-terminus and an N-terminus D: has no charge
B: might be an oligonucleotide
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17
Which of the following is most likely true about polysaccharides?
A: do not fold into three dimensional structures B: are glycans C: must be homopolysaccharides D: are never branched
B: are glycans
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18
Which statement about glycoconjugates is false?
A: the glycosaminoglycan chain of the proteoglycan can bind to extracellular proteins through electrostatic interactions B: glycolipids are found in specific organisms, such as golgi complexes C: glycosphingolipids play a role in signal transduction D: the oligosaccharide portions of glycoproteins are very heterogeneous
B: glycolipids are found in specific organisms, such as golgi complexes
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19
Which statement is true about the three dimensional structure of DNA?
A: Native DNA consists of two parallel chains in a right handed double helical arrangement B: complementary base pairs, A-=(three bonds)C and G=T are formed by hydrogen bonding between chains in the helix C: The base pairs are stacked parallel to the long axis of the double helix D: the offset pairing of the two strands creates a major groove on the surface of the duplex
C: The base pairs are stacked parallel to the long axis of the double helix
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20
The process of separating strands of DNA double helix is known as:
Which statement is false about nucleotides and nucleic acids undergoing non-enzymatic transformations?
A: several nucleotide bases undergo spontaneous loss of their exocyclic amino groups B: Hydrolysis of the N-B-glycosyl bond between the base and the pentose creates a DNA lesion called an AP site C: Ionizing radiation induces the condensation of two ethylene groups to form a cyclobutene ring D: UV irradiation can result in a 6-4 photoproduct, a type of pyrimidine dimer
C: Ionizing radiation induces the condensation of two ethylene groups to form a cyclobutene ring
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22
Mutations in DNA can result from:
A: deamination of ribose B: UV-induced purine dimers C: alkylation of the phosphodiester bond D: oxidation of deoxyribose
D: oxidation of deoxyribose
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23
Which of the following is most likely true about oligonucleotide, pACGUAC?
A: the nucleotide at the 3' end has a phosphate at its 3' hydroxyl B: the nucleotide at the 3' end is a purine C: the nucleotide at the 5' end has a 5' hydroxyl D: the nucleotide at the 5' end has a phosphate on its 5' hydroxyl
D: the nucleotide at the 5' end has a phosphate on its 5' hydroxyl
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24
Which of the following is true about properties of fatty acids?
A: are highly oxidized storage forms of hydrocarbons B: can be branched or unbranched C: never exceed 20 carbons in length, by definition
B: can be branched or unbranched
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25
Which of the following fatty acids is less stable?
T/F: melting point decreases as the number of double bonds increases in fatty acid
true
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27
- a parent compound or compounds of sphingolipids
A: phospholipases are B: glycerol-3-phosphate C: sphingomyelinds are D: ceramides are
D: ceramides are
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28
Which statement regarding cholesterol is false?
A: It is the precursor for steroid hormones B: It is the precursor for bile acids C: It is usually not a component of eukaryotic membranes D: It has a hydrophilic functional group
C: It is usually not a component of eukaryotic membranes
A: phosphorylated derivatives of phosphatidylinosital regulate cell structure and metabolism B: Extracellular signals activate a specific phospholipase C in the membrane, which hydrolyzes PIP2 to release two products that act as intracellular messengers C: PIP3 is a potent regulator of protein kinases
C: PIP3 is a potent regulator of protein kinases
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31
A novel subclass of thromboxane was discovered in lipids isolated from a newly discovered poison dart from the Amazon valley. What unique structural feature is likely present in these lipids?
A: four conjugated double bonds B: a six membered ring C: a long chain alcohol bound to a double ring D: fiver membered ring
B: a six membered ring
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32
What product of the preparatory phase of glycolysis is required, but at twice the concentration, as a reactant in the payoff phase?
A: dihydroxyacetone phosphate B: NAD+ C: ADP
C: ADP
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33
How is glucose kept inside the cell, against a concentration gradient?
A: glucose is kept inside the cell by active transport pumps B: glucose is kept inside the cell by conversion to glucose 6 phosphate C: glucose is kept inside the cell through rapid conversion to pyruvate D: there are no glucose transporters to pump glucose out of the cell
B: glucose is kept inside the cell by conversion to glucose 6 phosphate
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34
How is glucose 6 phosphate prevented from leaving the cell?
A: It is prevented from leaving by active transport pump B: there are no phospho-glucose specific transporters C: glucose 6 phosphate is rapidly converted to fructose 6 phosphate
B: there are no phospho-glucose specific transporters
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35
How are glycolysis, ethanol fermentation, and lactate fermentation all related?
A: all are regulated by the ATP/ADP mass action ratio B: all three produce CO2 C: all can proceed in the absence of oxygen D: all require pyruvate
C: all can proceed in the absence of oxygen
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36
The reaction catalyzed by glyceraldehyde 3 phosphate dehydrogenase oxidizes an aldehyde group. How does this reaction conserve much of the free energy of oxidation?
A: through the formation of a carboxylic acid B: through the formation of an acyl phosphate C: through the formation of a carbon carbon bond D: through the formation of ATP
B: through the formation of an acyl phosphate
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37
Which sugar cannot be fed into the glycolytic pathway?
A: sucrose B: mannose C: glycogen D: cellulose
D: cellulose
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38
Which enzyme is specific to the gluconeogeneic pathway?
A: glucose 6 phosphatase B: pyruvate carboxylase C: PEP carboxykinase D: all of the answers are correct
D: all of the answers are correct
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39
Which carbons of the original glucose are phosphorylated in the two molecules of glyceraldehyde 3 phosphate?
A: C1 and C2 B: C3 and C4 C: C1 and C6 D: C1 and C4
C: C1 and C6
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40
Which reaction of glycolysis includes substrate level phosphorylation, a very different mechanisms that oxidative phosphorylation?
Which of the following statements is true of galactosemia?
A: results from defective or absent lactase in the intestine B: is a disorder that affects how the body processes a simple sugar called galactose C: the ability to metabolize galactose results in galactosemia
B: is a disorder that affects how the body processes a simple sugar called galactose
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44
Which nucleotide is required for glycogen synthesis?
A: GTP B: UTP C: cAMP D: ATP
B: UTP
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45
Glyconeogenesis:
A: begins the production of a new glycogen molecule with the reactions of glycogenin B: involves the action of glycogen debranching enzyme C: involves transfer of glucose from CDP glucose to a nonreducing end of glycogen D: only occurs in the liver and muscle
A: begins the production of a new glycogen molecule with the reactions of glycogenin
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46
In muscle, what are two allosteric activators of glycogen phosphorylase?
A: Mg2+ and ATP B: Ca2+ and AMP C: AMP and glucose D: cAMP and acetyl-CoA
B: Ca2+ and AMP
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47
Which vitamin is a coenzyme to the pyruvate dehydrogenase (PDH) complex?
A: pantothenate B: thiamine pyrophosphate C: niacin D: riboflavin E: all of the answers are correct
E: all of the answers are correct
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48
Which two chemical mechanisms change to acetyl-CoA in the pyruvate dehydrogenase complex?
A: dehydrogenation and oxidation B: decarboxylation and condensation C: condensation and dehydrogenation D: dehydrogenation and decarboxylation
D: dehydrogenation and decarboxylation
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49
What is the advantage to having an enzyme complex, as in pyruvate dehydrogenase (PDH) complex?
A: multiple steps can be regulated at one point B: products do not need to diffuse to become substrates for the next enzymatic reaction C: products cannot be scavenged by other enzymes or pathways D: conservation of energy drives the reactions E: all of the answers are correct
E: all of the answers are correct
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50
The citrate synthase step of the citric acid cycle:
A: is freely reversible under physiological conditions B: does not involve ATP hydrolysis C: is considered to be both the first and last step of the cycle
B: does not involve ATP hydrolysis
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51
Which statement regarding isocitrate dehydrogenase is false?
A: in eukaryotes, there is an NAD+ dependent form in mitochondria and an NAD+ independent form found in both mitochondria and cytosol B: it catalyzes a reversible reaction under physiological conditions C: it catalyzes an oxidative decarboxylation
B: it catalyzes a reversible reaction under physiological conditions
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52
Which enzyme of the citric acid cycle is capable of a substrate level phosphorylation?
Which statement regarding the citric acid cycle is false?
A: The PDH complex is considered to be an enzyme of the citric acid cycle B: succinate dehydrogenase is an integral membrane protein C: for the complete conversion of glucose to CO2, approximately 32 ATP can be synthesized
A: The PDH complex is considered to be an enzyme of the citric acid cycle
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55
The conversion of 1 mol of fructose 1,6 bisphosphate to 2 mol of pyruvate by the glycolytic pathway results in a net formation of:
A: 1 mol of NAD+ and 2 mol of ATP B: 1 mold NADH and 1 mol ATP C: 2 mol of NAD+ and 4 mol of ATP D: 2 mol of NADH and 2 mol ATP E: 2 mol of NADH and 4 mol of ATP
E: 2 mol of NADH and 4 mol of ATP
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56
Which of the following glycolytic steps does not most likely occur between glyceraldehyde 3 phosphate and 3 phosphoglycerate?
A: ATP synthesis B: catalysis by phosphorylation kinase C: oxidation of NADH and NAD+ D: the formation of 1,3 bisphosphoglycerate E: utilization of Pi
NOT A: ATP synthesis, Quizlet says C: oxidation of NADH and NAD+
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57
Which of the following statements is not true concerning glycolysis in anaerobic muscle?
A: fructose 1,6 bisphosphate is one of the enzymes of the pathway B: it is an endergonic process C: it results in net synthesis of of ATP D: it results in synthesis of NADH E: its rate is slowed by a high [ATP]/[ADP] ration
B: it is an endergonic process
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58
Which of these cofactors participates directly in most of the oxidation-reduction reactions in the fermentation of glucose to lactate?
Which of the following enzymes is used in both glycolysis and gluconeogenesis?
A: 3 phosphoglycerate kinase B: glucose 6 phosphae C: phosphofructokinase 1 D: the conversion of pyruvate to lactate
A: 3 phosphoglycerate kinase
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60
Which statement about carbohydrate metabolism is false?
A: The overall strategy for metabolizing the common monosacharides is to convert them into glycolytic intermediates B: Galactose metabolism requires a nucleotide C: mannose is phosphorylated by hexokinase D: galactosemia results from defective or absent lactase in the intestine
D: galactosemia results from defective or absent lactase in the intestine
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61
Glycerophospholipids do not contain:
A: fatty acids B: ester linkages C: glycerol D: a mono or disaccharide
D: a mono or disaccharide
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62
Where do we store triacylglycerol (triglyceride)?
A: in the lumen of the ER B: in the mitochondria C: in the lipid droplet D: in the nucleus
C: in the lipid droplet
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63
Which statement is false?
A: Naturally occurring fatty acids usually have an even number of carbons B: wax esters contain long chain fatty acids and long chain alcohols C: triacylglycerols are polar due to their ester functional groups D: the number of C-C double bonds in a fatty acids affects its melting point
C: triacylglycerols are polar due to their ester functional groups
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64
Which statement regarding linoleic acid (18:2(delta sup 9,12)) is false?
A: It has one carboxylic acid functional group B: it has two double bonds C: it has 20 carbons D: it has C-C double bonds between carbons 9 and 10
C: it has 20 carbons
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65
Which of the following biomolecules is an allosteric activator of BOTH citric acid cycle and glycolysis pathways?
A: ATP B: NAD+ C: ADP D: Citrate E: NADH
C: ADP
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66
The glyoxylate cycle is remarkably similar to the citric acid cycle but differs in several important ways. Which important molecule is conserved by by the glyoxylate cycle but NOT the citric acid cycle?
Which of the following statements is/are true about the regulation of glucose metabolism through glycolysis and the citric acid cycle?
A: High ADP levels stimulate glycolysis and the citric acid cycle B: High NADP levels inhibit glycolysis and the citric acid cycle C: High citrate levels inhibit glycolysis D: all of the answers are correct
D: all of the answers are correct
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73
Which statement regarding the citric acid cycle is false?
A: The PDH complex is considered to be an enzyme of the citric acid cycle B: Succinate dehydrogenase is an integral membrane protein C: For the conversion of glucose to CO2, approximately 32 ATP can be synthesized D: Decarboxylation of pyruvate takes place on the thiamine pyrophosphate (TPP) of pyruvate dehydrogenase (E1) of the pryuvate dehydrogenase reaction
A: The PDH complex is considered to be an enzyme of the citric acid cycle
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- is required as a cofactor for the conversion of succinate to fumarate in the citric acid cycle
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