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A) a carbohydrate.
B) a hexose.
Which of the following monosaccharides is not an aldose?
The reference compound for naming D and L isomers of sugars is:
When two carbohydrates are epimers:
A) one is a pyranose, the other a furanose.
B) one is an aldose, the other a ketose.
C) they differ in length by one carbon.
D) they differ only in the configuration around one carbon atom.
E) they rotate plane-polarized light in the same direction.
Which of the following is an epimeric pair?
A) D-glucose and D-glucosamine
B) D-glucose and D-mannose
C) D-glucose and L-glucose
D) D-lactose and D-sucrose
E) L-mannose and L-fructose
Which of following is an anomeric pair?
A) D-glucose and D-fructose
B) D-glucose and L-fructose
C) D-glucose and L-glucose
D) a-D-glucose and b-D-glucose
E) a-D-glucose and b-L-glucose
When the linear form of glucose cyclizes, the product is a(n):
Which of the following pairs is interconverted in the process of mutarotation?
A) D-glucose and D-fructose
B) D-glucose and D-galactose
C) D-glucose and D-glucosamine
D) D-glucose and L-glucose
E) a-D-glucose and b-D-glucose
Which of the following is not a reducing sugar?
Which of the following monosaccharides is not a carboxylic acid?
E) muramic acid
D-Glucose is called a reducing sugar because it undergoes an oxidation-reduction reaction at the anomeric carbon. One of the products of this reaction is:
E) muramic acid.
Hemoglobin glycation is a process where is attached to hemoglobin.
A) glycerol; covalently
B) glucose; enzymatically
C) glucose; non-enzymatically
D) N-acetyl-galactosamine; enzymatically
E) galactose; non-enzymatically
From the abbreviated name of the compound Gal(b1 ® 4)Glc, we know that:
A) C-4 of glucose is joined to C-1 of galactose by a glycosidic bond.
B) the compound is a D-enantiomer.
C) the galactose residue is at the reducing end.
D) the glucose is in its pyranose form.
E) the glucose residue is the b anomer.
Starch and glycogen are both polymers of:
Which of the following statements about starch and glycogen is false?
A) Amylose is unbranched; amylopectin and glycogen contain many (a1 ® 6) branches.
B) Both are homopolymers of glucose.
C) Both serve primarily as structural elements in cell walls.
D) Both starch and glycogen are stored intracellularly as insoluble granules.
E) Glycogen is more extensively branched than starch.
Which of the following is a heteropolysaccharide?
The basic structure of a proteoglycan consists of a core protein and a:
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 cysteine.
Which of the following is a dominant feature of the outer membrane of the cell wall of gram-negative bacteria?
A) amphipathic molecules.
B) hydrophobic molecules.
C) specific lipids.
D) specific oligosaccharides.
E) specific peptides.
Why is it surprising that the side chains of tryptophan residues in proteins can interact with lectins?
A) because the side chain of tryptophan is hydrophilic and lectins are hydrophobic.
B) because the side chain of tryptophan is (-) charged and lectins are generally (+) charged or neutral.
C) because the side chain of tryptophan can make hydrogen bonds and lectins cannot.
D) because the side chain of tryptophan is hydrophobic and lectins are generally hydrophilic.
E) None of the above.
The compound that consists of ribose linked by an N-glycosidic bond to N-9 of adenine is:
A) a deoxyribonucleoside.
B) a purine nucleotide.
C) a pyrimidine nucleotide.
D) adenosine monophosphate.
A major component of RNA but not of DNA is:
The difference between a ribonucleotide and a deoxyribonucleotide is:
A) a deoxyribonucleotide has an —H instead of an —OH at C-2.
B) a deoxyribonucleotide has a configuration; ribonucleotide has the b configuration at C-1.
C) a ribonucleotide has an extra —OH at C-4.
D) a ribonucleotide has more structural flexibility than deoxyribonucleotide.
E) a ribonucleotide is a pyranose, deoxyribonucleotide is a furanose.
Which one of the following is true of the pentoses found in nucleic acids?
A) C-5 and C-1 of the pentose are joined to phosphate groups.
B) C-5 of the pentose is joined to a nitrogenous base, and C-1 to a phosphate group.
C) The bond that joins nitrogenous bases to pentoses is an O-glycosidic bond.
D) The pentoses are always in the b-furanose forms.
E) The straight-chain and ring forms undergo constant interconversion.
The phosphodiester bonds 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.
The phosphodiester bond that joins adjacent nucleotides in DNA:
A) associates ionically with metal ions, polyamines, and proteins.
B) is positively charged.
C) is susceptible to alkaline hydrolysis.
D) Links C-2 of one base to C-3 of the next.
E) links C-3 of deoxyribose to N-1 of thymine or cytosine.
The alkaline hydrolysis of RNA does not produce:
A) 2'- AMP.
The DNA oligonucleotide abbreviated pATCGAC:
A) has 7 phosphate groups.
B) has a hydroxyl at its 3' end.
C) has a phosphate on its 3' end.
D) has an A at its 3' end.
E) violates Chargaff's rules.
For the oligoribonucleotide 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.
E) the nucleotide at the 5' end is a pyrimidine.
The nucleic acid bases:
A) absorb ultraviolet light maximally at 280 nm.
B) are all about the same size.
C) are relatively hydrophilic.
D) are roughly planar.
E) can all stably base-pair with one another.
Which of the following statements concerning the tautomeric forms of bases such as uracil is correct?
A) The all-lactim form contains a ketone group.
B) The lactam form contains an alcohol group.
C) The lactam form predominates at neutral pH.
D) They are geometric isomers.
E) They are stereoisomers.
In a double-stranded nucleic acid, cytosine typically base-pairs with:
In the Watson-Crick model for the DNA double helix (B form) the A–T and G–C base pairs share which one of the following properties?
A) The distance between the two glycosidic (base-sugar) bonds is the same in both base pairs, within a few tenths of an angstrom.
B) The molecular weights of the two base pairs are identical.
C) The number of hydrogen bonds formed between the two bases of the base pair is the same.
D) The plane of neither base pair is perpendicular to the axis of the helix.
E) The proton-binding groups in both base pairs are in their charged or ionized form.
The experiment of Avery, MacLeod, and McCarty in which nonvirulent bacteria were made virulent by transformation was significant because it showed that:
A) bacteria can undergo transformation.
B) genes are composed of DNA only.
C) mice are more susceptible to pneumonia than are humans.
D) pneumonia can be cured by transformation.
E) virulence is determine genetically.
Chargaff's rules state that in typical DNA:
A) A = G.
B) A = C.
C) A = U.
D) A + T = G + C.
E) A + G = T + C.
In the Watson-Crick structure of DNA, the:
A) absence of 2'-hydroxyl groups allows bases to lie perpendicular to the helical axis.
B) adenine content of one strand must equal the thymine content of the same strand.
C) nucleotides are arranged in the A-form.
D) purine content (fraction of bases that are purines) must be the same in both strands.
E) two strands are parallel.
In the Watson-Crick model of DNA structure:
the distance between two adjacent bases in one strand is about 3.4 Å.
Which of the following is not true of all naturally occurring DNA?
A) Deoxyribose units are connected by 3',5'-phosphodiester bonds.
B) The amount of A always equals the amount of T.
C) The ratio A+T/G+C is constant for all natural DNAs.
D) The two complementary strands are antiparallel.
E) Two hydrogen bonds form between A and T.
In the Watson-Crick model of DNA structure (now called B-form DNA):
A) a purine in one strand always hydrogen bonds with a purine in the other strand.
B) A–T pairs share three hydrogen bonds.
C) G–C pairs share two hydrogen bonds.
D) the 5' ends of both strands are at one end of the helix.
E) the bases occupy the interior of the helix.
The double helix of DNA in the B-form is stabilized by:
A) covalent bonds between the 3' end of one strand and the 5' end of the other.
B) hydrogen bonding between the phosphate groups of two side-by-side strands.
C) hydrogen bonds between the riboses of each strand.
D) nonspecific base-stacking interaction between two adjacent bases in the same strand.
E) ribose interactions with the planar base pairs.
In nucleotides and nucleic acids, syn and anti conformations relate to:
A) base stereoisomers.
B) rotation around the phosphodiester bond.
C) rotation around the sugar-base bond.
D) sugar pucker.
E) sugar stereoisomers.
B-form DNA in vivo is a ________-handed helix, _____ Å in diameter, with a rise of ____ Å per base pair.
A) left; 20; 3.9
B) right; 18; 3.4
C) right; 18; 3.6
D) right; 20; 3.4
E) right; 23; 2.6
In double-stranded DNA:
A) only a right-handed helix is possible.
B) sequences rich in A–T base pairs are denatured less readily than those rich in G–C pairs.
C) the sequence of bases has no effect on the overall structure.
D) the two strands are parallel.
E) the two strands have complementary sequences.
Which of the following is a palindromic sequence?
Triple-helical DNA structures can result from Hoogsteen (non Watson-Crick) interactions. These interactions are primarily:
A) covalent bonds involving deoxyribose.
B) covalent bonds involving the bases.
C) hydrogen bonds involving deoxyribose.
D) hydrogen bonds involving the bases.
E) hydrophobic interactions involving the bases.
A) are less stable than double-stranded regions of DNA.
B) can be observed in the laboratory, but probably have no biological relevance.
C) can form between two self-complementary regions of the same single strand of RNA.
D) do not occur.
E) have the two strands arranged in parallel (unlike those of DNA, which are antiparallel).
When double-stranded DNA is heated at neutral pH, which change does not occur?
A) The absorption of ultraviolet (260 nm) light increases.
B) The covalent N-glycosidic bond between the base and the pentose breaks.
C) The helical structure unwinds.
D) The hydrogen bonds between A and T break.
E) The viscosity of the solution decreases.
Which of the following deoxyoligonucleotides will hybridize with a DNA containing the sequence (5')AGACTGGTC(3')?
The ribonucleotide polymer (5')GTGATCAAGC(3') could only form a double-stranded structure with:
In comparison with DNA-DNA double helices, the stability of DNA-RNA and RNA-RNA helices is:
A) DNA-DNA > DNA-RNA > RNA-RNA.
B) DNA-DNA > RNA-RNA > DNA-RNA.
C) RNA-DNA > RNA-RNA > DNA-DNA.
D) RNA-RNA > DNA-DNA > DNA-RNA.
E) RNA-RNA > DNA-RNA > DNA-DNA.
In the laboratory, several factors are known to cause alteration of the chemical structure of DNA. The factor(s) likely to be important in a living cell is (are):
B) low pH.
D) UV light.
E) both C and D.
Compounds that generate nitrous acid (such as nitrites, nitrates, and nitrosamines) change DNA molecules by:
A) breakage of phosphodiester bonds.
B) deamination of bases.
D) formation of thymine dimers.
E) transformation of A ® T.
In DNA sequencing by the Sanger (dideoxy) method:
In the chemical synthesis of DNA:
A) the dimethoxytrityl (DMT) group catalyzes formation of the phosphodiester bond.
B) the direction of synthesis is 5' to 3'.
C) the maximum length of oligonucleotide that can be synthesized is 8-10 nucleotides.
D) the nucleotide initially attached to the silica gel support will become the 3' end of the finished product.
E) the protecting cyanoethyl groups are removed after each step.
In living cells, nucleotides and their derivatives can serve as:
A) carriers of metabolic energy.
B) enzyme cofactors.
C) intracellular signals.
D) precursors for nucleic acid synthesis.
E) all of the above.
A) act at the membrane to restrict the passage of certain molecules into the cell.
B) are highly specialized ribonucleases that degrade mRNA soon after its synthesis.
C) are sequence-specific DNA endonucleases.
D) are very specific proteases that cleave peptides at only certain sequences.
E) catalyze the addition of a certain amino acid to a specific tRNA.
The biological role of restriction enzymes is to:
A) aid recombinant DNA research.
B) degrade foreign DNA that enters a bacterium.
C) make bacteria resistant to antibiotics.
D) restrict the damage to DNA by ultraviolet light.
E) restrict the size of DNA in certain bacteria.
The size of the DNA region specifically recognized by type II restriction enzymes is typically:
A) 4 to 6 base pairs.
B) 10 to 15 base pairs.
C) 50 to 60 base pairs.
D) 200 to 300 base pairs.
E) about the size of an average gene.
Which of the following statements about type II restriction enzymes is false?
A) Many make staggered (off-center) cuts within their recognition sequences.
B) Some cut DNA to generate blunt ends.
C) They are part of a bacterial defense system in which foreign DNA is cleaved.
D) They cleave and ligate DNA.
E) They cleave DNA only at recognition sequences specific to a given restriction enzyme.
Certain restriction enzymes produce cohesive (sticky) ends. This means that they:
A) cut both DNA strands at the same base pair.
B) cut in regions of high GC content, leaving ends that can form more hydrogen bonds than ends of high AT content.
C) make a staggered double-strand cut, leaving ends with a few nucleotides of single-stranded DNA protruding.
D) make ends that can anneal to cohesive ends generated by any other restriction enzyme.
E) stick tightly to the ends of the DNA they have cut.
In the laboratory, recombinant plasmids are commonly introduced into bacterial cells by:
A) electrophoresis – a gentle low-voltage gradient draws the DNA into the cell.
B) infection with a bacteriophage that carries the plasmid.
D) mixing plasmids with an extract of broken cells.
E) transformation – heat shock of the cells incubated with plasmid DNA in the presence of CaCl2.
The E. coli recombinant plasmid pBR322 has been widely utilized in genetic engineering experiments. pBR322 has all of the following features except:
a number of palindromic sequences near the EcoRI site, which permit the plasmid to assume a conformation that protects newly inserted DNA from nuclease degradation.
Which of the following statements regarding plasmid cloning vectors is correct?
A) Circular plasmids do not require an origin of replication to be propagated in E. coli.
B) Foreign DNA fragments up to 45,000 base pairs can be cloned in a typical plasmid.
C) Plasmids do not need to contain genes that confer resistance to antibiotics.
D) Plasmid vectors must carry promoters for inserted gene fragments.
E) The copy number of plasmids may vary from a few to several hundred.
A convenient cloning vector with which to introduce foreign DNA into E. coli is a(n):
A) E. coli chromosome.
B) messenger RNA.
D) yeast "ARS" sequence.
E) yeast transposable element.
In genetic engineering, in vitro packaging is used to:
A) cut a desired region out of the host bacterium's chromosome.
B) ensure that genetically engineered bacteria are not accidentally released into the environment.
C) incorporate recombinant DNA into infectious bacteriophage particles.
D) place an antibiotic resistance gene in a plasmid.
E) splice a desired gene into a plasmid.
Which of the following does not apply to the construction or use of a DNA library?
A) Determining the location of a particular DNA sequence in a DNA library requires a suitable hybridization probe.
B) Genomic libraries are better for expressing gene products than cDNA libraries.
C) Many segments of DNA from a cellular genome are cloned.
D) Specialized DNA libraries can be made by cloning DNA copies of mRNAs.
E) The DNA copies of mRNA found in a cDNA library are made by reverse transcriptase.
The PCR reaction mixture does not include:
A) all four deoxynucleoside triphosphates.
B) DNA containing the sequence to be amplified.
C) DNA ligase.
D) heat-stable DNA polymerase.
E) oligonucleotide primer(s).
Which of the following statements about the polymerase chain reaction (PCR) is false?
A) DNA amplified by PCR can be cloned.
B) DNA is amplified at many points within a cellular genome.
C) Newly synthesized DNA must be heat-denatured before the next round of DNA synthesis begins.
D) The boundaries of the amplified DNA segment are determined by the synthetic oligonucleotides used to prime DNA synthesis.
E) The technique is sufficiently sensitive that DNA sequences can be amplified from a single animal or human hair.
RFLP is a:
A) bacteriophage vector for cloning DNA.
B) genetic disease.
C) plasmid vector for cloning DNA.
E) variation in DNA base sequence.
Current estimates indicate that humans have about ________ genes.
Current estimates indicate that ________ % of the human genome is translated into protein.
A) less than 0.5
B) roughly 1.5
C) roughly 10
D) roughly 25
E) more than 50
A) Human, fruit fly, E. coli bacterium
B) E. coli bacterium, human, fruit fly
C) E. coli bacterium, fruit fly, human
D) fruit fly, E. coli bacterium, human
E) fruit fly, human, E. coli bacterium
Which one of the following analytical techniques does not help illuminate a gene’s cellular function?
A) DNA microarray analysis
B) Protein chip analysis
C) Southern blotting
D) Two-dimensional gel electrophoresis
E) Two-hybrid analysis
The technique known as two hybrid analysis for detecting interacting gene products depends on:
stimulation of transcription by interaction of two Gal4p domains via fused protein sequences.
A common cloning strategy for introducing foreign genes into plants with Agrobacterium employs all the following features except:
A) a selectable antibiotic marker such as kanamycin resistance.
B) a shuttle vector with 25 bp T-DNA repeats flanking the foreign gene of choice.
C) a Ti plasmid lacking its T-DNA segment.
D) active vir gene products from the altered Ti plasmid.
E) an ability to induce crown gall formation in infected leaves.
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