BIOL213 Lecture Notes - Lecture 4: Anomer, Glycobiology, Ketose
Lecture 4 – Carbohydrates and Glycobiology
Carbohydrates:
• named so because many have the formula Cn(H2O)n
• Produced from CO2 and H2O via photosynthesis in plants
• Range from as small as glyceraldehyde to as large as amylopectin. CHOs are not
polymers of any one single monomer - they are wide range of compounds.
• Fulfill a variety of functions including energy source and storage, structural
components and informational molecules.
Monosaccharides:
• Two families - aldoses (have an aldehyde group) and ketoses (have a ketone group)
• Monosaccharides are named depending on the number of Cs - triose = 3, pentose =
5.
• The carbons are numbered beginning at the end of the chain nearest the carbonyl
group.
• Examples of a 5 carbon aldose (aldopentose) and ketose (ketopentose)
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Lecture 4 – Carbohydrates and Glycobiology
• Anomeric carbon is the chiral carbon that is furthermost from the carbonyl
carbon. In the molecule below the anomeric carbon is red and the carbonyl
carbon is green. This anomeric carbon dictates whether the molecule is in the D or
the L form.
• Chiral carbon has 4 different groups attached to it. Where the OH group sits on
the chiral carbon dictates whether it is classified as being in the D form or the L
form. If the OH is on the right side it is a D form; if it is on the left side it is the L
form.
• Stereoisomers: each chiral centre gives rise to two different configurations and
thus increases the number of stereoisomers by a factor of two (2n). Eg. Hexose
(aldohexose) has four chiral carbons, so it has 2^4 = 16 stereoisomers.
No. stereoisomers = 2^no. chiral carbons.
• Epimers are two sugars that difference only in the configuration around one
carbon. These three sugars below are the most abundant sugars in nature.
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Document Summary
Carbohydrates: named so because many have the formula cn(h2o)n, produced from co2 and h2o via photosynthesis in plants, range from as small as glyceraldehyde to as large as amylopectin. Chos are not polymers of any one single monomer - they are wide range of compounds: fulfill a variety of functions including energy source and storage, structural components and informational molecules. Lecture 4 carbohydrates and glycobiology: anomeric carbon is the chiral carbon that is furthermost from the carbonyl carbon. In the molecule below the anomeric carbon is red and the carbonyl carbon is green. This anomeric carbon dictates whether the molecule is in the d or the l form: chiral carbon has 4 different groups attached to it. Where the oh group sits on the chiral carbon dictates whether it is classified as being in the d form or the l form. Hexose (aldohexose) has four chiral carbons, so it has 2^4 = 16 stereoisomers.
