Question 1

Draw the Haworth structure of b-D-ribofuranose.

Accepted Answer

The answer of Draw the Haworth structure of b-D-ribofuranose....

Question 2

An optically active D-aldopentose produced an optically inactive aldaric acid upon treatment with HNO3. When this aldopentose was subjected to a Ruff degradation, a D-aldopentose was generated. This aldotetrose gave an optically inactive alditol upon reduction with NaBH4. Use these data to provide the structure of the starting D-aldopentose.

Accepted Answer

Question 3

Two D-aldopentoses give the same D-aldotetrose upon Ruff degradation. The two aldopentoses are:

Accepted Answer

A)  enantiomers. 
B)  meso compounds. 
C)  C2 epimers. 
D)  C4 epimers. 
E)  D-glucose and D-galactose. 
A)  enantiomers. 
B)  meso compounds. 
C)  C2 epimers. 
D)  C4 epimers. 
E)  D-glucose and D-galactose.

Question 4

Which of the following correctly describes the structural relationship between D-ribose and L-lyxose?

Accepted Answer

A)  diastereomers and epimers 
B)  diastereomers but not epimers 
C)  enantiomers 
D)  constitutional isomers 
E)  not isomers 
A)  diastereomers and epimers 
B)  diastereomers but not epimers 
C)  enantiomers 
D)  constitutional isomers 
E)  not isomers

Question 5

Provide the structure of cytidine.

Accepted Answer

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Question 6

A linkage of two anomeric carbons is found in:

Accepted Answer

A)  cellobiose. 
B)  sucrose. 
C)  gentiobiose. 
D)  amylose. 
E)  chitin. 
A)  cellobiose. 
B)  sucrose. 
C)  gentiobiose. 
D)  amylose. 
E)  chitin.

Question 7

When L-erythrose is treated with NaBH4,

Accepted Answer

A)  a 70:30 mixture of enantiomeric alditols results. 
B)  a 50:50 mixture of enantiomeric alditols results. 
C)  a meso alditol is produced. 
D)  the product mixture contains two diastereomeric alditols. 
E)  an optically active alditol is produced. 
A)  a 70:30 mixture of enantiomeric alditols results. 
B)  a 50:50 mixture of enantiomeric alditols results. 
C)  a meso alditol is produced. 
D)  the product mixture contains two diastereomeric alditols. 
E)  an optically active alditol is produced.

Question 8

Which of the following descriptions of the nucleoside uridine does not apply to the structure of the molecule?

Accepted Answer

A)  The uracil base is directly bonded to the 1' position of ribofuranose in the α position. 
B)  The ribofuranose moiety is found in only the D configuration. 
C)  Nitrogen, at position 1 in the uracil base, is directly bonded to the ribofuranose moiety. 
D)  The 5' OH group is replaced with phosphate(s) in the nucleotide structure. 
E)  none of the above 
A)  The uracil base is directly bonded to the 1' position of ribofuranose in the α position. 
B)  The ribofuranose moiety is found in only the D configuration. 
C)  Nitrogen, at position 1 in the uracil base, is directly bonded to the ribofuranose moiety. 
D)  The 5' OH group is replaced with phosphate(s) in the nucleotide structure. 
E)  none of the above

Question 9

Provide the structure of the major organic product which results when D-ribose is subjected to a Ruff degradation.

Accepted Answer

The answer of Provide the structure of the major organic...

Question 10

How many molecules of carbon dioxide and water are needed to make a molecule of glucose in photosynthesis?

Accepted Answer

A)  5 CO2 and 5 H2O 
B)  5 CO2 and 6 H2O 
C)  6 CO2 and 6 H2O 
D)  6 CO2 and 2 H2O 
E)  2 CO2 and 2 H2O 
A)  5 CO2 and 5 H2O 
B)  5 CO2 and 6 H2O 
C)  6 CO2 and 6 H2O 
D)  6 CO2 and 2 H2O 
E)  2 CO2 and 2 H2O

Question 11

Two molecules of phenylhydrazine condense with each molecule of a given aldohexose to give an osazone in which:

Accepted Answer

A)  a phenylhydrazone derivative is formed at C1 only. 
B)  a phenylhydrazone is formed at C2 only. 
C)  both C1 and C2 are converted to phenylhydrazones. 
D)  C1 and C2 are connected by a carbon-carbon double bond. 
E)  C1 and C2 are connected via a cyclic hydrazone. 
A)  a phenylhydrazone derivative is formed at C1 only. 
B)  a phenylhydrazone is formed at C2 only. 
C)  both C1 and C2 are converted to phenylhydrazones. 
D)  C1 and C2 are connected by a carbon-carbon double bond. 
E)  C1 and C2 are connected via a cyclic hydrazone.

Question 12

What derivative results when an aldopentose is treated with excess phenylhydrazine and catalytic acid?

Accepted Answer

A)  pyranose 
B)  furanose 
C)  aldonic acid 
D)  glycoside 
E)  osazone 
A)  pyranose 
B)  furanose 
C)  aldonic acid 
D)  glycoside 
E)  osazone

Question 13

How might one separate α-D-glucopyranose from a solution also containing β-D-glucopyranose.

Accepted Answer

Concentrate the solu

Question 14

Show the Haworth of α-L-fructofuranose and the Fischer diagram of L-fructose.

Accepted Answer

The answer of Show the Haworth of α-L-fructofuranose and the...

Question 15

List the aldopentoses described by the mnemonic "Ribs are extra lean."

Accepted Answer

ribose, ar

Question 16

A D-aldopentose is subjected to Kiliani-Fischer chain lengthening and the resulting mixture is oxidized using nitric acid. The two distinct products both show optical activity. From this one can conclude that the original D-aldopentose:

Accepted Answer

A)  must be D-ribose. 
B)  is either D-ribose or D-arabinose. 
C)  must be D-xylose. 
D)  is either D-xylose or D-arabinose. 
E)  must be D-lyxose. 
A)  must be D-ribose. 
B)  is either D-ribose or D-arabinose. 
C)  must be D-xylose. 
D)  is either D-xylose or D-arabinose. 
E)  must be D-lyxose.

Question 17

Which of the following descriptions apply to both dihydroxyacetone and D-fructofuranose? 
I. They are both ketoses.
II. They are both aldoses.
III. They are enatiomers of each other.
IV. They are diastereomers of each other.
V. They are epimers of each other.

Accepted Answer

A)  I 
B)  II 
C)  I and III 
D)  II and IV 
E)  II, IV and V 
A)  I 
B)  II 
C)  I and III 
D)  II and IV 
E)  II, IV and V

Question 18

A diastereomer is called erythro if its Fischer projection shows similar groups:

Accepted Answer

A)  opposite each other on the same carbon. 
B)  equally spaced about a central carbonyl. 
C)  directly above and below a central carbonyl. 
D)  on the same side of the molecule on adjacent carbons. 
E)  on opposite sides of the molecule on adjacent carbons. 
A)  opposite each other on the same carbon. 
B)  equally spaced about a central carbonyl. 
C)  directly above and below a central carbonyl. 
D)  on the same side of the molecule on adjacent carbons. 
E)  on opposite sides of the molecule on adjacent carbons.

Question 19

Draw the Haworth structure of a-D-glucopyranose.

Accepted Answer

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Question 20

Provide the Haworth structure of b-D-ribopyranose.

Accepted Answer

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Exam 23: Carbohydrates and Nucleic Acids

Draw the Haworth structure of b-D-ribofuranose.

Two D-aldopentoses give the same D-aldotetrose upon Ruff degradation. The two aldopentoses are:

Which of the following correctly describes the structural relationship between D-ribose and L-lyxose?

Provide the structure of cytidine.

A linkage of two anomeric carbons is found in:

When L-erythrose is treated with NaBH4,

Which of the following descriptions of the nucleoside uridine does not apply to the structure of the molecule?

Provide the structure of the major organic product which results when D-ribose is subjected to a Ruff degradation.

How many molecules of carbon dioxide and water are needed to make a molecule of glucose in photosynthesis?

Two molecules of phenylhydrazine condense with each molecule of a given aldohexose to give an osazone in which:

What derivative results when an aldopentose is treated with excess phenylhydrazine and catalytic acid?

How might one separate α-D-glucopyranose from a solution also containing β-D-glucopyranose.

Show the Haworth of α-L-fructofuranose and the Fischer diagram of L-fructose.

List the aldopentoses described by the mnemonic "Ribs are extra lean."

A D-aldopentose is subjected to Kiliani-Fischer chain lengthening and the resulting mixture is oxidized using nitric acid. The two distinct products both show optical activity. From this one can conclude that the original D-aldopentose:

Which of the following descriptions apply to both dihydroxyacetone and D-fructofuranose? I. They are both ketoses. II. They are both aldoses. III. They are enatiomers of each other. IV. They are diastereomers of each other. V. They are epimers of each other.

A diastereomer is called erythro if its Fischer projection shows similar groups:

Draw the Haworth structure of a-D-glucopyranose.

Provide the Haworth structure of b-D-ribopyranose.

Introduction and Review

Structure and Properties of Organic Molecules

Structure and Stereochemistry of Alkanes

The Study of Chemical Reactions

Stereochemistry

Alkyl Halides: Nucleophilic Substitution and Elimination

Structure and Synthesis of Alkenes

Reactions of Alkenes

Alkynes

Structure and Synthesis of Alcohols

Reactions of Alcohols

Infrared Spectroscopy and Mass Spectrometry

Nuclear Magnetic Resonance Spectroscopy

Ethers, Epoxides, and Thioethers

Conjugated Systems, Orbital Symmetry, and Ultraviolet Spectroscopy

Aromatic Compounds

Reactions of Aromatic Compounds

Ketones and Aldehydes

Amines

Carboxylic Acids

Carboxylic Acid Derivatives

Condensations and Alpha Substitutions of Carboxyl Compounds

Amino Acids, Peptides, and Proteins

Lipids

Synthetic Polymers

Filters

When L-erythrose is treated with NaBH₄,

_{How many molecules of ca}_{rbon dioxide and water are needed to make a molecule of glucose in photosynthesis?}