Question 1

Which of the following amino acids are rich in histones?

Accepted Answer

A) alanine and glycine 
B) glutamic acid and aspartic acid 
C) lysine and arginine 
D) lysine and alanine 
A) alanine and glycine 
B) glutamic acid and aspartic acid 
C) lysine and arginine 
D) lysine and alanine C

Question 2

An intact 4 kb plasmid has a 50% G+C content,and a 4 kb fragment of E.coli chromosomal DNA has a 55% G+C content.Which of the following is NOT correct when comparing the two?

Accepted Answer

A) The Tm of the plasmid would be less than the Tm of the chromosomal DNA. 
B) The c0t1/2 value (time required to renature 50% of the DNA molecules)of the plasmid would be more than that of the chromosomal DNA. 
C) The plasmid DNA and chromosomal DNA would both show approximately a 30%-40% increase in their absorption at 260 nm upon heating to 90°C. 
D) The plasmid DNA would contain more negative supercoiling than the chromosomal DNA fragments. 
A) The Tm of the plasmid would be less than the Tm of the chromosomal DNA. 
B) The c0t1/2 value (time required to renature 50% of the DNA molecules)of the plasmid would be more than that of the chromosomal DNA. 
C) The plasmid DNA and chromosomal DNA would both show approximately a 30%-40% increase in their absorption at 260 nm upon heating to 90°C. 
D) The plasmid DNA would contain more negative supercoiling than the chromosomal DNA fragments. B

Question 3

How is radioactivity incorporated into newly synthesized DNA using the chain termination protocol for sequencing DNA?

Accepted Answer

A) One of the dNTPs is labelled with 32P. 
B) The primer strand is labelled with 32P. 
C) The 5'-end is labelled with 32P. 
D) The dideoxynucleotide is labelled with 32P. 
A) One of the dNTPs is labelled with 32P. 
B) The primer strand is labelled with 32P. 
C) The 5'-end is labelled with 32P. 
D) The dideoxynucleotide is labelled with 32P. A

Question 4

Which of the following is a characteristic of in vitro DNA synthesis?

Accepted Answer

A) DNA polymerase adds nucleotides in a 3'?5' direction. 
B) Correct hydrogen bonding is the primary check of the newly synthesized DNA. 
C) The primer strand of DNA determines the nucleotides added. 
D) DNA polymerase copies the template strand of DNA. 
A) DNA polymerase adds nucleotides in a 3'?5' direction. 
B) Correct hydrogen bonding is the primary check of the newly synthesized DNA. 
C) The primer strand of DNA determines the nucleotides added. 
D) DNA polymerase copies the template strand of DNA.

Question 5

How do urea and formamide denature dsDNA?

Accepted Answer

A) by intercalating between base pairs and disrupting van der Waals interactions 
B) by forming ionic bonds with the backbone phosphates 
C) by competing effectively with the H-bonding between the base pairs 
D) by changing the pH to cause hydrolysis 
A) by intercalating between base pairs and disrupting van der Waals interactions 
B) by forming ionic bonds with the backbone phosphates 
C) by competing effectively with the H-bonding between the base pairs 
D) by changing the pH to cause hydrolysis

Question 6

The hyperchromic shift occurs when dsDNA is denatured.At what wavelength is there an increase in the absorption as a result of this shift?

Accepted Answer

A) 200 nm 
B) 220 nm 
C) 240 nm 
D) 260 nm 
A) 200 nm 
B) 220 nm 
C) 240 nm 
D) 260 nm

Question 7

Which of the following major interactions assist in folding components of the secondary structure of tRNA together and bending the cloverleaf into a stable L-shaped tertiary form?

Accepted Answer

A) van der Waals 
B) ionic 
C) base-pairing 
D) electrostatic interactions 
A) van der Waals 
B) ionic 
C) base-pairing 
D) electrostatic interactions

Question 8

Nucleic acid hybridization is a common technique used in molecular biology.Which of the following procedures does NOT use this technique?

Accepted Answer

A) investigation of evolutionary relationships 
B) examination of specific genes against a vast background 
C) carrying out specific probe-based isolation of proteins 
D) quantifying gene expression 
A) investigation of evolutionary relationships 
B) examination of specific genes against a vast background 
C) carrying out specific probe-based isolation of proteins 
D) quantifying gene expression

Question 9

Which of the following statements is NOT correct regarding the linking number?

Accepted Answer

A) It is a basic parameter characterizing supercoiled DNA. 
B) L = T + W. 
C) It is the number of times that 2 strands are intertwined,providing both strands remain covalently intact. 
D) L = 40 in a relaxed circular DNA duplex of 400 bp. 
A) It is a basic parameter characterizing supercoiled DNA. 
B) L = T + W. 
C) It is the number of times that 2 strands are intertwined,providing both strands remain covalently intact. 
D) L = 40 in a relaxed circular DNA duplex of 400 bp.

Question 10

Which of the following is NOT a DNA intercalating agent?

Accepted Answer

A) ethidium bromide 
B) actinomycin D 
C) acridine orange 
D) streptomycin 
A) ethidium bromide 
B) actinomycin D 
C) acridine orange 
D) streptomycin

Question 11

Which of the following is a characteristic of rRNA strands?

Accepted Answer

A) interstrand sequence complementarity 
B) the absence of modified ribonucleotides 
C) an anticodon loop 
D) highly folded patterns,including many stem-loop structures 
A) interstrand sequence complementarity 
B) the absence of modified ribonucleotides 
C) an anticodon loop 
D) highly folded patterns,including many stem-loop structures

Question 12

Which of the following stabilizes the DNA double-helix structure?

Accepted Answer

A) The sugar-phosphate backbones are oriented in parallel directions. 
B) Bases stack together through hydrophobic interactions and van der Waals forces. 
C) The glycosidic bonds holding paired bases are directly across the helix from one another. 
D) Appropriate base pairing builds a polymer whose external dimensions are not consistent. 
A) The sugar-phosphate backbones are oriented in parallel directions. 
B) Bases stack together through hydrophobic interactions and van der Waals forces. 
C) The glycosidic bonds holding paired bases are directly across the helix from one another. 
D) Appropriate base pairing builds a polymer whose external dimensions are not consistent.

Question 13

How are individual amino acids attached to their corresponding tRNAs?

Accepted Answer

A) through an ester linkage to the 3'-OH in the acceptor stem 
B) through an amide linkage to the anticodon loop 
C) through an amide linkage to the adenine ring at the 3'-end of the tRNA 
D) through a phosphoester linkage to the 5'-end of the tRNA 
A) through an ester linkage to the 3'-OH in the acceptor stem 
B) through an amide linkage to the anticodon loop 
C) through an amide linkage to the adenine ring at the 3'-end of the tRNA 
D) through a phosphoester linkage to the 5'-end of the tRNA

Question 14

Which of the following pairs of nucleotides,present in high concentrations,would result in a higher DNA melting temperature?

Accepted Answer

A) A:T 
B) A:U 
C) G:C 
D) I:G 
A) A:T 
B) A:U 
C) G:C 
D) I:G

Question 15

The UV absorption decrease associated with ssDNAs reannealing can be plotted on a c₀t curve.Which of the following does this graph indicate?

Accepted Answer

A) that more complex DNAs take longer to renature 
B) that more double-stranded RNAs take longer to renature 
C) that more simple DNAs take longer to renature 
D) that more single-stranded RNAs take longer to renature 
A) that more complex DNAs take longer to renature 
B) that more double-stranded RNAs take longer to renature 
C) that more simple DNAs take longer to renature 
D) that more single-stranded RNAs take longer to renature

Question 16

Which of the following is the function of DNA topoisomerases?

Accepted Answer

A) packaging DNA into nucleosomes 
B) forming cruciform DNA 
C) unwinding G:C-rich areas in DNA 
D) breaking 1 or more strands of DNA,winding them tighter or looser,and rejoining the ends 
A) packaging DNA into nucleosomes 
B) forming cruciform DNA 
C) unwinding G:C-rich areas in DNA 
D) breaking 1 or more strands of DNA,winding them tighter or looser,and rejoining the ends

Question 17

Which of the following terms is for the naturally occurring,self-replicating,extra-chromosomal DNA molecules found in bacteria that carry genes specifying novel metabolic capacity advantageous to the bacterium?

Accepted Answer

A) probes 
B) cruciform 
C) toroidal DNA 
D) plasmids 
A) probes 
B) cruciform 
C) toroidal DNA 
D) plasmids

Question 18

Which of the following types of structures potentially forms from DNA sequences that are inverted repeats?

Accepted Answer

A) a secondary structure known as a cruciform 
B) a tertiary structure known as a cruciform 
C) a secondary structure known as a palindrome 
D) a tertiary structure known as a palindrome 
A) a secondary structure known as a cruciform 
B) a tertiary structure known as a cruciform 
C) a secondary structure known as a palindrome 
D) a tertiary structure known as a palindrome

Question 19

Which of the following is NOT a secondary structure component of tRNA?

Accepted Answer

A) acceptor stem 
B) β-turn l 
C) anticodon loop 
D) TYC loop 
A) acceptor stem 
B) β-turn l 
C) anticodon loop 
D) TYC loop

Question 20

Which of the following terms defines the process that occurs when ssDNA reassociates with other ssDNA?

Accepted Answer

A) diffusion 
B) reannealing 
C) melting 
D) solidifying 
A) diffusion 
B) reannealing 
C) melting 
D) solidifying

Exam 25: Structure of Nucleic Acids

Which of the following amino acids are rich in histones?

An intact 4 kb plasmid has a 50% G+C content,and a 4 kb fragment of E.coli chromosomal DNA has a 55% G+C content.Which of the following is NOT correct when comparing the two?

How is radioactivity incorporated into newly synthesized DNA using the chain termination protocol for sequencing DNA?

Which of the following is a characteristic of in vitro DNA synthesis?

How do urea and formamide denature dsDNA?

The hyperchromic shift occurs when dsDNA is denatured.At what wavelength is there an increase in the absorption as a result of this shift?

Which of the following major interactions assist in folding components of the secondary structure of tRNA together and bending the cloverleaf into a stable L-shaped tertiary form?

Nucleic acid hybridization is a common technique used in molecular biology.Which of the following procedures does NOT use this technique?

Which of the following statements is NOT correct regarding the linking number?

Which of the following is NOT a DNA intercalating agent?

Which of the following is a characteristic of rRNA strands?

Which of the following stabilizes the DNA double-helix structure?

How are individual amino acids attached to their corresponding tRNAs?

Which of the following pairs of nucleotides,present in high concentrations,would result in a higher DNA melting temperature?

The UV absorption decrease associated with ssDNAs reannealing can be plotted on a c₀t curve.Which of the following does this graph indicate?

Which of the following is the function of DNA topoisomerases?

Which of the following terms is for the naturally occurring,self-replicating,extra-chromosomal DNA molecules found in bacteria that carry genes specifying novel metabolic capacity advantageous to the bacterium?

Which of the following types of structures potentially forms from DNA sequences that are inverted repeats?

Which of the following is NOT a secondary structure component of tRNA?

Which of the following terms defines the process that occurs when ssDNA reassociates with other ssDNA?

The Facts of Life: Chemistry Is the Logic of Biological Phenomena

Water: the Medium of Life

Thermodynamics of Biological Systems

Amino Acids

Proteins: Their Primary Structure and Biological Functions

Proteins: Secondary, tertiary, and Quaternary Structure

Carbohydrates and the Glycoconjugates of Cell Surfaces

Lipids

Lipid Biosynthesis

Membranes and Membrane Transport

The Reception and Transmission of Extracellular Information

Enzymes Kinetics and Specificity

Mechanisms of Enzyme Action

Enzyme Regulation

Molecular Motors

Nutrition and the Organization of Metabolism

Glycolysis

The Tricarboxylic Acid Cycle

Electron Transport and Oxidative Phosphorylation

Photosynthesis

Gluconeogenesis, glycogen Metabolism, and the Pentose Phosphate Pathway

Fatty Acid Catabolism

Nitrogen Acquisition and Amino Acid Metabolism

Nucleotides and Nucleic Acids

Synthesis and Degradation of Nucleotides

Recombinant Dna: Cloning and Creation of Chimeric Genes

DNA Metabolism: Replication, recombination, and Repair

Transcription and the Regulation of Gene Expression

Protein Synthesis

Post-Transcriptional Regulation of Gene Expression

Completing the Protein Life Cycle: Folding, processing, and Degradation

Metabolic Integration and Organ Specialization

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