Integrated SequencePhysics Chemistry Organic Biology

Web Resources



  click if a link is broken



Special points of emphasis

Functional Groups in Organic Chemistry

Reactions of Alcohols and Ethers

Carbohydrates

Oxidation-Reduction

Oxidation-Reduction in Organic Chemistry

A very important method for detection of carbohydrates is the use of periodic acid-Schiff (PAS) reagent. Periodate oxidation of the hydroxyl groups cleaves sugars and generates aldehydes. These aldehydes are then detected with Schiff's; reagent, which transforms the aldehydes into colored imines.

The imine product of such a reaction is the source of the term 'Schiff base'. 'Schiff base' has been adopted as a general term for a stable imine, or in other words, one in which the nitrogen atom is not connected to a hydrogen but to an aryl or alkyl group. Remember this because a recurring motif in metabolism is the formation of a Schiff' base (imine) between an aldehyde or ketone substrate and a lysine residue of an enzyme. You might not think it is fair, but from an MCAT writer's perspective, Schiff base is the kind of thing you put in a passage as a comprehension hurdle. It's technically organic chemistry, but you only talk about it for five minutes in general organic chemistry. You spend quite a bit of time on it in biochemistry.




Functional Groups in Organic Chemistry

Reactions of Aldehydes and Ketones

Carbohydrates

Oxidation-Reduction

Oxidation-Reduction in Organic Chemistry

The term 'reducing sugars' denotes carbohydrates that give positive tests with Benedict's reagent, a solution of the citrate complex of copper (II) sulfate which oxidizes aliphatic aldehydes. Of monosaccharides, aldoses and ketoses both test positively (ketoses because of keto-enol tautomerism). Carbohydrates containing a free hemiacetal group are reducing sugars because the hemiacetal is in equilibrium with the open chain form. Fehling's solution and Tollen's reagent are also used as tests for reducing sugars.







The WikiPremed MCAT Course is a free comprehensive course in the undergraduate level general sciences. Undergraduate level physics, chemistry, organic chemistry and biology are presented by this course as a unified whole within a spiraling curriculum.

Please read our policies on privacy and shipping & returns.  Contact Us.
MCAT is a registered trademark of the Association of American Medical Colleges, which does not endorse the WikiPremed Course.


Creative Commons License
The work of WikiPremed is published under a Creative Commons Attribution Share Alike 3.0 License. There are elements of work here, such as a subset of the images in the archive from WikiPedia, that originated as GNU General Public License works, so take care to follow the unique stipulations of that license in printed reproductions. You can use the resources here for commercial or non-commercial purposes, but please give attribution and a link to the production credits and edit history of the resource. For the works here which began as my individual work, please attribute "John Wetzel, an author at wikipremed.com".