Question 1

In DNA sequencing by the Sanger (dideoxy)method:

Accepted Answer

A) radioactive dideoxy ATP is included in each of four reaction mixtures before enzymatic synthesis of complementary strands. 
B) specific enzymes are used to cut the newly synthesized DNA into small pieces,which are then separated by electrophoresis. 
C) the dideoxynucleotides must be present at high levels to obtain long stretches of DNA sequence. 
D) the role of the dideoxy CTP is to occasionally terminate enzymatic synthesis of DNA where Gs occur in the template strands. 
E) the template DNA strand is radioactive. 
A) radioactive dideoxy ATP is included in each of four reaction mixtures before enzymatic synthesis of complementary strands. 
B) specific enzymes are used to cut the newly synthesized DNA into small pieces,which are then separated by electrophoresis. 
C) the dideoxynucleotides must be present at high levels to obtain long stretches of DNA sequence. 
D) the role of the dideoxy CTP is to occasionally terminate enzymatic synthesis of DNA where Gs occur in the template strands. 
E) the template DNA strand is radioactive.

Question 2

Based on the spontaneous deamination of cytosine,explain why it is advantageous for DNA to contain thymine,not uracil.

Accepted Answer

Cytosine undergoes spontaneous deaminati

Question 3

Describe briefly how noncovalent interactions contribute to the three-dimensional shapes of RNA molecules.

Accepted Answer

Hydrogen-bonding in regions of complemen

Question 4

The double helix of DNA in the B-form is stabilized by:

Accepted Answer

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. 
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.

Question 5

The alkaline hydrolysis of RNA does not produce:

Accepted Answer

A) 2'- AMP. 
B) 2',3'-cGMP. 
C) 2'-CMP. 
D) 3',5'-cAMP. 
E) 3'-UMP. 
A) 2'- AMP. 
B) 2',3'-cGMP. 
C) 2'-CMP. 
D) 3',5'-cAMP. 
E) 3'-UMP.

Question 6

Write a double-stranded DNA sequence containing a six-nucleotide palindrome.

Accepted Answer

Any double-stranded sequence that has th

Question 7

In nucleotides and nucleic acids,syn and anti conformations relate to:

Accepted Answer

A) base stereoisomers. 
B) rotation around the phosphodiester bond. 
C) rotation around the sugar-base bond. 
D) sugar pucker. 
E) sugar stereoisomers. 
A) base stereoisomers. 
B) rotation around the phosphodiester bond. 
C) rotation around the sugar-base bond. 
D) sugar pucker. 
E) sugar stereoisomers.

Question 8

In a double-stranded nucleic acid,cytosine typically base-pairs with:

Accepted Answer

A) adenosine. 
B) guanine. 
C) inosine. 
D) thymine. 
E) uracil. 
A) adenosine. 
B) guanine. 
C) inosine. 
D) thymine. 
E) uracil.

Question 9

The difference between a ribonucleotide and a deoxyribonucleotide is:

Accepted Answer

A) a deoxyribonucleotide has an -H instead of an -OH at C-2. 
B) a deoxyribonucleotide has an -H instead of an -OH at C-3. 
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. 
A) a deoxyribonucleotide has an -H instead of an -OH at C-2. 
B) a deoxyribonucleotide has an -H instead of an -OH at C-3. 
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.

Question 10

A solution of DNA is heated slowly until the tm is reached.What is the likely structure of the DNA molecules at this temperature?

Accepted Answer

The DNA molecules are partially denature

Question 11

In the Watson-Crick model of DNA structure (now called B-form DNA):

Accepted Answer

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. 
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.

Question 12

Describe briefly what is meant by saying that two DNA strands are complementary.

Accepted Answer

The nucleotide sequences of complementar

Question 13

The phosphodiester bonds that link adjacent nucleotides in both RNA and DNA:

Accepted Answer

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. 
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.

Question 14

The difference between thymine and uracil is:

Accepted Answer

A) one methylene group on the pyrimidine ring. 
B) one methyl group on the pyrimidine ring. 
C) one hydroxyl group on the ribose ring. 
D) one amine group on the pyrimidine ring. 
E) one methyl group on the purine ring. 
A) one methylene group on the pyrimidine ring. 
B) one methyl group on the pyrimidine ring. 
C) one hydroxyl group on the ribose ring. 
D) one amine group on the pyrimidine ring. 
E) one methyl group on the purine ring.

Question 15

The compound that consists of ribose linked by an N-glycosidic bond to N-9 of adenine is:

Accepted Answer

A) a deoxyribonucleoside. 
B) a purine nucleotide. 
C) a pyrimidine nucleotide. 
D) adenosine monophosphate. 
E) adenosine. 
A) a deoxyribonucleoside. 
B) a purine nucleotide. 
C) a pyrimidine nucleotide. 
D) adenosine monophosphate. 
E) adenosine.

Question 16

Based on Chargaff's rules,which of the following are possible base compositions for double-stranded DNA?

Accepted Answer

The answer of Based on Chargaff's rules,which of the following...

Question 17

In living cells,nucleotides and their derivatives can serve as:

Accepted Answer

A) carriers of metabolic energy. 
B) enzyme cofactors. 
C) intracellular signals. 
D) precursors for nucleic acid synthesis. 
E) all of the above. 
A) carriers of metabolic energy. 
B) enzyme cofactors. 
C) intracellular signals. 
D) precursors for nucleic acid synthesis. 
E) all of the above.

Question 18

The experiment of Avery,MacLeod,and McCarty in which nonvirulent bacteria were made virulent by transformation was significant because it showed that:

Accepted Answer

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. 
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.

Question 19

In the Watson-Crick model of DNA structure:

Accepted Answer

A) both strands run in the same direction,3' $\rightarrow$5';they are parallel. 
B) phosphate groups project toward the middle of the helix,where they are protected from interaction with water. 
C) T can form three hydrogen bonds with either G or C in the opposite strand. 
D) the distance between the sugar backbone of the two strands is just large enough to accommodate either two purines or two pyrimidines. 
E) the distance between two adjacent bases in one strand is about 3.4 Å. 
A) both strands run in the same direction,3' $\rightarrow$5';they are parallel. 
B) phosphate groups project toward the middle of the helix,where they are protected from interaction with water. 
C) T can form three hydrogen bonds with either G or C in the opposite strand. 
D) the distance between the sugar backbone of the two strands is just large enough to accommodate either two purines or two pyrimidines. 
E) the distance between two adjacent bases in one strand is about 3.4 Å.

Question 20

Compounds that generate nitrous acid (such as nitrites,nitrates,and nitrosamines)change DNA molecules by:

Accepted Answer

A) breakage of phosphodiester bonds. 
B) deamination of bases. 
C) depurination. 
D) formation of thymine dimers. 
E) transformation of A $\rightarrow$ T. 
A) breakage of phosphodiester bonds. 
B) deamination of bases. 
C) depurination. 
D) formation of thymine dimers. 
E) transformation of A $\rightarrow$ T.

Exam 8: Nucleotides and Nucleic Acids

In DNA sequencing by the Sanger (dideoxy)method:

Based on the spontaneous deamination of cytosine,explain why it is advantageous for DNA to contain thymine,not uracil.

Describe briefly how noncovalent interactions contribute to the three-dimensional shapes of RNA molecules.

The double helix of DNA in the B-form is stabilized by:

The alkaline hydrolysis of RNA does not produce:

Write a double-stranded DNA sequence containing a six-nucleotide palindrome.

In nucleotides and nucleic acids,syn and anti conformations relate to:

In a double-stranded nucleic acid,cytosine typically base-pairs with:

The difference between a ribonucleotide and a deoxyribonucleotide is:

A solution of DNA is heated slowly until the tm is reached.What is the likely structure of the DNA molecules at this temperature?

In the Watson-Crick model of DNA structure (now called B-form DNA):

Describe briefly what is meant by saying that two DNA strands are complementary.

The phosphodiester bonds that link adjacent nucleotides in both RNA and DNA:

The difference between thymine and uracil is:

The compound that consists of ribose linked by an N-glycosidic bond to N-9 of adenine is:

Based on Chargaff's rules,which of the following are possible base compositions for double-stranded DNA?

In living cells,nucleotides and their derivatives can serve as:

The experiment of Avery,MacLeod,and McCarty in which nonvirulent bacteria were made virulent by transformation was significant because it showed that:

In the Watson-Crick model of DNA structure:

Compounds that generate nitrous acid (such as nitrites,nitrates,and nitrosamines)change DNA molecules by:

The Foundations of Biochemistry

Water

Amino Acids, peptides, and Proteins

The Three-Dimensional Structure of Proteins

Protein Function

Enzymes

Carbohydrates and Glycobiology

Recombinant Dna Technology

Lipids

Biological Membranes and Transport

Biosignaling

Principles of Bioenergetics

Glycolysis, gluconeogenesis, and the Pentose Phosphate Pathway

Principles of Metabolic Regulation

The Citric Acid Cycle

Fatty Acid Catabolism

Amino Acid Oxidation and the Production of Urea

Oxidative Phosphorylation and Photophosphorylation

Carbohydrate Biosynthesis in Plants and Bacteria

Lipid Biosynthesis

Biosynthesis of Amino Acids, nucleotides, and Related Molecules

Integration and Hormonal Regulation of Mammalian Metabolism

Genes and Chromosomes

Dna Metabolism

Rna Metabolism

Protein Metabolism

Regulation of Gene Expression

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A solution of DNA is heated slowly until the t_m is reached.What is the likely structure of the DNA molecules at this temperature?