BCH 3025 MIDTERM LATEST SET EXAM

BCH 3025 MIDTERM LATEST SET EXAM Double-stranded regions of RNA: - -Can form between two self-complementary regions of the same single strand of RNA Which of the following is a palindromic sequence? - -GGATCC CCTAGG The compound that consists of ribose linked by an N-glycosidic bond to N-9 of adenine is: - -Adenosine In the Watson-Crick model of DNA structure (now called B-form DNA): - -The bases occupy the interior of the helix Which of the following is not true of all naturally occurring DNA? - -The ratio A+T/G+C is constant for all natural DNAs The phosphodiester bonds that link adjacent nucleotides in both RNA and DNA: - -Join the 3' hydroxyl of one nucleotide to the 5' hydroxyl of the next In the Watson-Crick model of DNA structure: - -The distance between two adjacent bases in one strand is about 3.4 Å The difference between a ribonucleotide and a deoxyribonucleotide is: - -A deoxyribonucleotide has an —H instead of an —OH at C-2 Triple-helical DNA structures can result from Hoogsteen (non Watson-Crick) interactions. These interactions are primarily: - -Hydrogen bonds involving the bases The phosphodiester bonds that link adjacent nucleotides in both RNA and DNA: - -Join the 3' hydroxyl of one nucleotide to the 5' hydroxyl of the next The "energy carrier" ATP is an example of a(n): - -Ribonucleosidetriphosphate 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? - -The distance between the two glycosidic (base-sugar) bonds is the same in both base pairs, within a few tenths of an angstro Which one of the following is true of the pentoses found in nucleic acids? - -The pentoses are always in the beta-furanose forms BCH 3025 BCH 3025 A major component of RNA but not of DNA is: - -Uracil For the oligoribonucleotide pACGUAC: - -The nucleotide at the 5' end has a phosphate on its 5' hydroxyl The experiment of Avery, MacLeod, and McCarty in which nonvirulent bacteria were made virulent by transformation was significant because it showed that: - -Genes are composed of DNA only When double-stranded DNA is heated at neutral pH, which change does not occur? - The covalent N-glycosidic bond between the base and the pentose breaks B-form DNA in vivo is a ________-handed helix, _____ Å in diameter, with a rise of ____ Å per base pair. - -Right; 20; 3.4 In comparison with DNA-DNA double helices, the stability of DNA-RNA and RNA-RNA helices is: - -RNA-RNA DNA-RNA DNA-DNA In double-stranded DNA: - -The two strands have complementary sequences n nucleotides and nucleic acids, syn and anti conformations relate to: - -Rotation around the sugar-base bond The phosphodiester bond that joins adjacent nucleotides in DNA: - -Associates ionically with metal ions, polyamines, and proteins The ribonucleotide polymer (5')GTGATCAAGC(3') could only form a double-stranded structure with: - -(5')GCTTGATCAC(3') The double helix of DNA in the B-form is stabilized by: - -Nonspecific base-stacking interaction between two adjacent bases in the same strand Compounds that generate nitrous acid (such as nitrites, nitrates, and nitrosamines) change DNA molecules by: - -Deamination of bases In living cells, nucleotides and their derivatives can serve as: - -All of the listed answers Which of the following statements concerning the tautomeric forms of bases such as uracil is correct? - -The lactam form predominates at neutral pH In a double-stranded nucleic acid, cytosine typically base-pairs with: - -Guanine The DNA oligonucleotide abbreviated pATCGAC: - -Has a hydroxyl at its 3' end The nucleic acid bases: - -Are roughly planar BCH 3025 BCH 3025 The alkaline hydrolysis of RNA does not produce: - -3',5'-cAMP Chargaff's rules state that in typical DNA: - -A +G =T +C Which of the following deoxyoligonucleotides will hybridize with a DNA containing the sequence (5')AGACTGGTC(3')? - -(5')GACCAGTCT(3') In DNA sequencing by the Sanger (dideoxy) method: - -The role of the dideoxy CTP is to occasionally terminate enzymatic synthesis of DNA where Gs occur in the template strands In nucleotides and nucleic acids, syn and anti conformations relate to: - -Rotation around the sugar-base bond In the chemical synthesis of DNA: - -The nucleotide initially attached to the silica gel support will become the 3' end of the finished product In the Watson-Crick structure of DNA, the: - -Absence of 2'-hydroxyl groups allows bases to lie perpendicular to the helical axis In comparison with DNA-DNA double helices - -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): - -Oxygen and UV light Rank the following organisms in order from smallest genome (number of base pairs of DNA) to largest genome. - -E. coli bacterium, fruit fly, human Current estimates indicate that humans have about ________ genes. - -30,000 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 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 degradatio The size of the DNA region specifically recognized by type II restriction enzymes is typically: - -4 to 6 base pairs BCH 3025 BCH 3025 A common cloning strategy for introducing foreign genes into plants with Agrobacterium employs all the following features except: - -A shuttle vector with 25 bp T-DNA repeats flanking the foreign gene of choice restriction enzymes: - -Are sequence-specific DNA endonucleases Certain restriction enzymes produce cohesive (sticky) ends. This means that they - Make a staggered double-strand cut, leaving ends with a few nucleotides of single stranded DNA protruding Current estimates indicate that ________ % of the human genome is translated into protein. - -Roughly1.5 Rank the following organisms in order from smallest genome (number of base pairs of DNA) to largest genome. - -E. coli bacterium, fruit fly, human Which of the following statements about the polymerase chain reaction (PCR) is false? - -DNA is amplified at many points within a cellular genome Which one of the following analytical techniques does not help illuminate a gene's cellular function? - -Southern-blotting Which of the following enzymes use(s) ATP as a substrate? - -DNA ligase 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 The PCR reaction mixture does not include: - -DNAligase Which of the following statements about type II restriction enzymes is false? - -They cleave and ligate DNA RFLP is a: - -Variation in DNA base sequence Genomic and cDNA libraries have the following characteristics: - -cDNA has ests genomic does not Which of the following statements regarding plasmid cloning vectors is correct? - -The copy number of plasmids may vary from a few to several hundred DNA microarrays allow for assays of cellular - -Both RNA and DNA levels BCH 3025 BCH 3025 Certain restriction enzymes produce cohesive (sticky) ends. This means that they: - Make a staggered double-strand cut, leaving ends with a few nucleotides of single stranded DNA protruding The 25bp repeats that flank the T-DNA of agrobacterium are similar functionally to the: - -Retroviral Long Terminal Repeats Which of the following does not apply to the construction or use of a DNA library? - Genomic libraries are better for expressing gene products than cDNA libraries A convenient cloning vector with which to introduce foreign DNA into E. coli is a(n): - Plasmid The technique known as two hybrid analysis for detecting interacting gene products depend on: - -Stimulation of transcription by interaction of two Gal4p domains via fused protein sequences In the laboratory, recombinant plasmids are commonly introduced into bacterial cells by: - -Transformation - heat shock of the cells incubated with plasmid DNA in the presence of CaCl2 Novel genes that produce proteins never before found in nature, can be produced by: - Two of the above answers are correct In genetic engineering, in vitro packaging is used to: - -Incorporate recombinant DNA into infectious bacteriophage particles The biological role of restriction enzymes is to: - -Degrade foreign DNA that enters a bacterium Biological waxes are all: - -Esters of single fatty acids with long-chain alcohols Which of the following statements about sterols is true? - -All sterols share a fused-ring structure with four rings Which of the following statements about membrane lipids is true? - -Some sphingolipids include oligosaccharides in their structure A compound containing N-acetylneuraminic acid (sialic acid) is: - -GangliosideGM2 Which of the following is true of sphingolipids? - -Cerebrosides and gangliosides are sphingolipids BCH 3025 BCH 3025 An example of a glycerophospholipid that is involved in cell signaling is: - Phosphatidylinositol Which of the following statements is true of lipids? - -Many contain fatty acids in ester or amide linkage Which of the following statements concerning fatty acids is correct? - -One is the precursor of prostaglandins Which of the following is not true of sterols? - -They are commonly found in bacterial membranes Non-steroidal anti-inflammatory drugs (NSAIDS) like aspirin and ibuprofen act by blocking production of: - -Prostaglandins Which of the following best describes the cholesterol molecule? - -Amphipathic Tay-Sachs disease is the result of a genetic defect in the metabolism