Question 1

In a Haworth projection of a five-membered cyclic hemiacetal, ________.

Accepted Answer

A)  the C6 carbon is drawn on the right 
B)  the C2 carbon is drawn on the left 
C)  the ring oxygen is drawn in the front 
D)  the ring oxygen is drawn in the back 
E)  all hydroxyls are always on the same side of the molecule 
A)  the C6 carbon is drawn on the right 
B)  the C2 carbon is drawn on the left 
C)  the ring oxygen is drawn in the front 
D)  the ring oxygen is drawn in the back 
E)  all hydroxyls are always on the same side of the molecule

Question 2

The α and β anomers of a D-glucopyranose are related as ________.

Accepted Answer

A)  enantiomers 
B)  meso compounds 
C)  structural isomers 
D)  epimers 
E)  disaccharides 
A)  enantiomers 
B)  meso compounds 
C)  structural isomers 
D)  epimers 
E)  disaccharides

Question 3

Name the two purine bases which serve as components in ribonucleosides.

Accepted Answer

The answer of Name the two purine bases which serve...

Question 4

When L-(+)-lyxose is treated with nitric acid, which of the following results?

Accepted Answer

A)  a racemic mixture of aldaric acids 
B)  an optically active aldaric acid 
C)  an optically inactive aldaric acid 
D)  an optically active aldonic acid 
E)  an optically inactive aldonic acid 
A)  a racemic mixture of aldaric acids 
B)  an optically active aldaric acid 
C)  an optically inactive aldaric acid 
D)  an optically active aldonic acid 
E)  an optically inactive aldonic acid

Question 5

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 6

Compound A (C4H8O4) gives a positive test with Tollen's reagent. Treatment of A with bromine water produces an optically active compound B. Oxidation of A with nitric acid gives an optically inactive compound C. Compound A can be prepared from L-glyceraldehyde by a Kiliani-Fischer synthesis. What are the structures of A, B, and C?

Accepted Answer

Question 7

Which of the following represents a pair of epimers?

Accepted Answer

A)  D- and L-erythrose 
B)  D-erythrose and D-threose 
C)  D-arabinose and D-erythrose 
D)  D-arabinose and D-xylose 
E)  D-glyceraldehyde and D-threose 
A)  D- and L-erythrose 
B)  D-erythrose and D-threose 
C)  D-arabinose and D-erythrose 
D)  D-arabinose and D-xylose 
E)  D-glyceraldehyde and D-threose

Question 8

When D-(+)-xylose is treated with nitric acid, which of the following results?

Accepted Answer

A)  a racemic mixture of aldaric acids 
B)  an optically active aldaric acid 
C)  an optically inactive aldaric acid 
D)  an optically active aldonic acid 
E)  an optically inactive aldonic acid 
A)  a racemic mixture of aldaric acids 
B)  an optically active aldaric acid 
C)  an optically inactive aldaric acid 
D)  an optically active aldonic acid 
E)  an optically inactive aldonic acid

Question 9

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

Accepted Answer

Question 10

Draw the Haworth structure of β-D-glucopyranose.

Accepted Answer

The answer of Draw the Haworth structure of β-D-glucopyranose....

Question 11

Six-membered cyclic hemiacetals and five-membered cyclic hemiacetals are called, respectively, ________.

Accepted Answer

A)  mannoses and xyloses 
B)  maltoses and arabinoses 
C)  pyranoses and furanoses 
D)  glyoses and fructoses 
E)  none of the above 
A)  mannoses and xyloses 
B)  maltoses and arabinoses 
C)  pyranoses and furanoses 
D)  glyoses and fructoses 
E)  none of the above

Question 12

L-Ribulose may be classified as ________.

Accepted Answer

A)  an aldotetrose 
B)  an aldopentose 
C)  an aldohexose 
D)  a ketotetrose 
E)  a ketopentose 
A)  an aldotetrose 
B)  an aldopentose 
C)  an aldohexose 
D)  a ketotetrose 
E)  a ketopentose

Question 13

Provide the structure of deoxythymidine.

Accepted Answer

The answer of Provide the structure of deoxythymidine....

Question 14

Will methyl-β-D-talopyranoside undergo mutarotation? Why or why not?

Accepted Answer

No, because there is

Question 15

Provide the structure of the major organic product which results when methyl β-D-glucopyranoside is treated with excess acetic anhydride in pyridine.

Accepted Answer

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

Question 16

When a monosaccharide reacts to give the pyranose form from its open-chain form, how many distinct pyranose forms are possible?

Accepted Answer

A)  1 
B)  2 
C)  2n, where n is the number of carbons present 
D)  4n + 2, where n is the number of carbons present 
E)  4 
A)  1 
B)  2 
C)  2n, where n is the number of carbons present 
D)  4n + 2, where n is the number of carbons present 
E)  4

Question 17

Given the structure of D-altrose below, draw the structure of L-altrose.

Accepted Answer

The answer of Given the structure of D-altrose below, draw...

Question 18

What is the major organic product of the following reaction?

Accepted Answer

The answer of What is the major organic product of...

Question 19

What are the four common ribonucleosides?

Accepted Answer

cytidine,

Question 20

Draw the Haworth structure of α-D-glucopyranose.

Accepted Answer

The answer of Draw the Haworth structure of α-D-glucopyranose....

Exam 23: Carbohydrates and Nucleic Acids

In a Haworth projection of a five-membered cyclic hemiacetal, ________.

The α and β anomers of a D-glucopyranose are related as ________.

Name the two purine bases which serve as components in ribonucleosides.

When L-(+)-lyxose is treated with nitric acid, which of the following results?

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 represents a pair of epimers?

When D-(+)-xylose is treated with nitric acid, which of the following results?

Draw the Haworth structure of β-D-glucopyranose.

Six-membered cyclic hemiacetals and five-membered cyclic hemiacetals are called, respectively, ________.

L-Ribulose may be classified as ________.

Provide the structure of deoxythymidine.

Will methyl-β-D-talopyranoside undergo mutarotation? Why or why not?

Provide the structure of the major organic product which results when methyl β-D-glucopyranoside is treated with excess acetic anhydride in pyridine.

When a monosaccharide reacts to give the pyranose form from its open-chain form, how many distinct pyranose forms are possible?

Given the structure of D-altrose below, draw the structure of L-altrose.

What is the major organic product of the following reaction?

What are the four common ribonucleosides?

Draw the Haworth structure of α-D-glucopyranose.

Structure and Bonding

Acids and Bases; Functional Groups

Structure and Stereochemistry of Alkanes

The Study of Chemical Reactions

Stereochemistry

Alkyl Halides; Nucleophilic Substitution

Structure and Synthesis of Alkenes; Elimination

Reactions of Alkenes

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

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