Information about Pentose
A pentose is a monosaccharide with five carbon atoms.
They either have an aldehyde functional group in position 1 (aldopentoses), or a ketone functional group in position 2 (ketopentoses).
The aldopentoses have three chiral centres ("asymmetric carbon atoms") and so 8 different stereoisomers are possible.
The 4 D-aldopentoses are:
CH=O CH=O CH=O CH=O | | | | HC-OH HO-CH HC-OH HO-CH | | | | HC-OH HC-OH HO-CH HO-CH | | | | HC-OH HC-OH HC-OH HC-OH | | | | CH2OH CH2OH CH2OH CH2OH D-Ribose D-Arabinose D-Xylose D-Lyxose
A mnemonic suggested by a Cornell University undergraduate that can be used to remember the four D-aldopentoses is "ribs are extra lean."
The ketopentoses have 2 chiral centres and therefore 4 possible stereoisomers — ribulose (L- and D-form) and xylulose (L- and D-form).
The D-isomers of both are known to occur naturally as is the L-isomer of xylulose: CH2OH CH2OH | | C=O C=O | | HC-OH HO-CH | | HC-OH HC-OH | | CH2OH CH2OH D-Ribulose D-Xylulose
The aldehyde and ketone functional groups in these carbohydrates react with neighbouring hydroxyl functional groups to form intramolecular hemiacetals or hemiketals, respectively. The resulting ring structure is related to furan, and is termed a furanose. The ring spontaneously opens and closes, allowing rotation to occur about the bond between the carbonyl group and the neighbouring carbon atom — yielding two distinct configurations (α and β). This process is termed mutarotation.
Ribose is a constituent of RNA, and the related deoxyribose of DNA.
A mnemonic (pronounced IPA: /niːˈmɒnɪk/ in RP, /nɨˈmɑnɨk/
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They either have an aldehyde functional group in position 1 (aldopentoses), or a ketone functional group in position 2 (ketopentoses).
The aldopentoses have three chiral centres ("asymmetric carbon atoms") and so 8 different stereoisomers are possible.
The 4 D-aldopentoses are:
CH=O CH=O CH=O CH=O | | | | HC-OH HO-CH HC-OH HO-CH | | | | HC-OH HC-OH HO-CH HO-CH | | | | HC-OH HC-OH HC-OH HC-OH | | | | CH2OH CH2OH CH2OH CH2OH D-Ribose D-Arabinose D-Xylose D-Lyxose
A mnemonic suggested by a Cornell University undergraduate that can be used to remember the four D-aldopentoses is "ribs are extra lean."
The ketopentoses have 2 chiral centres and therefore 4 possible stereoisomers — ribulose (L- and D-form) and xylulose (L- and D-form).
The D-isomers of both are known to occur naturally as is the L-isomer of xylulose: CH2OH CH2OH | | C=O C=O | | HC-OH HO-CH | | HC-OH HC-OH | | CH2OH CH2OH D-Ribulose D-Xylulose
The aldehyde and ketone functional groups in these carbohydrates react with neighbouring hydroxyl functional groups to form intramolecular hemiacetals or hemiketals, respectively. The resulting ring structure is related to furan, and is termed a furanose. The ring spontaneously opens and closes, allowing rotation to occur about the bond between the carbonyl group and the neighbouring carbon atom — yielding two distinct configurations (α and β). This process is termed mutarotation.
Ribose is a constituent of RNA, and the related deoxyribose of DNA.
See also
Monosaccharides (from Greek : single, sacchar: sugar) are the simplest carbohydrates. They cannot be hydrolyzed into simpler sugars. They consist of one sugar and are usually colorless, water-soluble, crystalline solids. Some monosaccharides have a sweet taste.
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4, 2
(mildly acidic oxide)
Electronegativity 2.55 (Pauling scale)
Ionization energies
(more) 1st: 1086.5 kJmol−1
2nd: 2352.6 kJmol−1
3rd: 4620.5 kJmol−1
Atomic radius 70 pm
Atomic radius (calc.
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(mildly acidic oxide)
Electronegativity 2.55 (Pauling scale)
Ionization energies
(more) 1st: 1086.5 kJmol−1
2nd: 2352.6 kJmol−1
3rd: 4620.5 kJmol−1
Atomic radius 70 pm
Atomic radius (calc.
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atom (Greek ἄτομος or átomos meaning "indivisible") is the smallest particle still characterizing a chemical element.
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aldehyde is an organic compound containing a terminal carbonyl group. This functional group, which consists of a carbon atom which is bonded to a hydrogen atom and double-bonded to an oxygen atom (chemical formula O=CH-), is called the aldehyde group.
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In organic chemistry, functional groups (or moieties) are specific groups of atoms within molecules, that are responsible for the characteristic chemical reactions of those molecules.
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A ketone (pronounced as key tone) is either the functional group characterized by a carbonyl group (O=C) linked to two other carbon atoms or a chemical compound that contains this functional group.
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Stereoisomers are isomeric molecules whose atomic connectivity is the same but whose atomic arrangement in space is different.
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Enantiomers
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Ribose (ɹˈaɪbəʊs [1] , ɹˈaɪbəɹʊs [2] ), primarily seen as D -ribose, is an aldopentose — a monosaccharide containing five carbon atoms, and including an aldehyde functional group in its
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Arabinose is an aldopentose — a monosaccharide containing five carbon atoms, and including an aldehyde (CHO) functional group. It has chemical formula C5H10O5 and a molar mass of 150.13 g/mol.
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Xylose or wood sugar is an aldopentose — a monosaccharide containing five carbon atoms and including an aldehyde functional group. It has chemical formula C5H10O5. Xylose is found in the embryos of most edible plants.
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Lyxose is an aldopentose — a monosaccharide containing five carbon atoms, and including an aldehyde functional group. It has chemical formula C5H10O5.
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Not to be confused with pneumonic.
A mnemonic (pronounced IPA: /niːˈmɒnɪk/ in RP, /nɨˈmɑnɨk/
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Cornell University is a private university located in Ithaca, New York, USA. Its two medical campuses are in New York City and Education City, Qatar. The youngest member of the Ivy League, Cornell was founded in 1865 by Ezra Cornell and Andrew Dickson White as a coeducational,
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Ribulose is a ketopentose — a monosaccharide containing five carbon atoms, and including a ketone functional group. It has chemical formula C5H10O5.
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Xylulose is a ketopentose, a monosaccharide containing five carbon atoms, and including a ketone functional group. It has the chemical formula C5H10O5. In nature, it occurs in both the L - and D -enantiomers.
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Xylulose is a ketopentose, a monosaccharide containing five carbon atoms, and including a ketone functional group. It has the chemical formula C5H10O5. In nature, it occurs in both the L - and D -enantiomers.
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Ribulose is a ketopentose — a monosaccharide containing five carbon atoms, and including a ketone functional group. It has chemical formula C5H10O5.
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Xylulose is a ketopentose, a monosaccharide containing five carbon atoms, and including a ketone functional group. It has the chemical formula C5H10O5. In nature, it occurs in both the L - and D -enantiomers.
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Hydroxyl in chemistry stands for a molecule consisting of an oxygen atom and a hydrogen atom connected by a covalent bond. The neutral form is a hydroxyl radical and the hydroxyl anion is called a hydroxide.
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Intramolecular in chemistry describes a process or characteristic limited within the structure of a single molecule; a property or phenomenon limited to the extent of a single molecule.
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A hemiacetal is a functional group, or a compound containing this functional group, in the form of:
where R and R' are any alkyl groups.
A hemiacetal can react with an alcohol under acidic conditions to form an acetal, and can dissociate to form an aldehyde and an
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where R and R' are any alkyl groups.
A hemiacetal can react with an alcohol under acidic conditions to form an acetal, and can dissociate to form an aldehyde and an
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A hemiacetal is a functional group, or a compound containing this functional group, in the form of:
where R and R' are any alkyl groups.
A hemiacetal can react with an alcohol under acidic conditions to form an acetal, and can dissociate to form an aldehyde and an
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where R and R' are any alkyl groups.
A hemiacetal can react with an alcohol under acidic conditions to form an acetal, and can dissociate to form an aldehyde and an
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Furan, also known as furane and furfuran, is a heterocyclic organic compound. It is typically derived by the thermal decomposition of pentose-containing materials, cellolosic solids especially pine-wood.
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A furanose is a simple sugar that contains a five-membered furan-based ring structure and is a sub-terminal ketone which gives it reducing power.
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Structural properties
The furanose ring is a cyclic hemiacetal of an aldopentose or a cyclic hemiketal of a ketohexose...... Click the link for more information.
Mutarotation is the term given to the change in the specific rotation of plane polarized light, when it is passed through an aldohexose (a monosaccharides with six carbon atoms and H-C=O group).
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Ribose (ɹˈaɪbəʊs [1] , ɹˈaɪbəɹʊs [2] ), primarily seen as D -ribose, is an aldopentose — a monosaccharide containing five carbon atoms, and including an aldehyde functional group in its
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Left: An RNA strand, with its nitrogenous bases. Right: Double-stranded DNA.]] Ribonucleic acid or RNA is a nucleic acid polymer consisting of nucleotide monomers, which plays several important roles in the processes of translating genetic information from
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Deoxyribose, also known as D -Deoxyribose and 2-deoxyribose, is an aldopentose — a monosaccharide containing five carbon atoms, and including an aldehyde functional group.
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A triose is a monosaccharide containing three carbon atoms. There are only two trioses, an aldotriose (glyceraldehyde) and a ketotriose (dihydroxyacetone). Trioses are important in respiration.
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