Enantiomers have the same physical properties, such as melting point, but differ in the direction they rotate polarized light.Ī sugar is designated as being a D sugar or an L sugar according to how, in a Fischer projection of the molecule, the hydrogen atom and OH group are attached to the penultimate carbon atom, which is the carbon atom immediately before the terminal alcohol carbon atom. A molecule containing a chiral carbon is nonsuperimposable on its mirror image, and two molecules that are nonsuperimposable mirror images of each other are a special type of stereoisomer called enantiomers. These particular stereoisomers contain at least one chiral carbon, a carbon atom that has four different groups bonded to it. Many carbohydrates exist as stereoisomers, in which the three-dimensional spatial arrangement of the atoms in space is the only difference between the isomers. Cellulose, glycogen, and starch are polysaccharides. Most sugars are either monosaccharides or disaccharides. Those with two monosaccharide units are disaccharides, and those with many monosaccharide units are polysaccharides. The simplest carbohydrates are monosaccharides. All carbohydrates contain alcohol functional groups, and either an aldehyde or a ketone group (or a functional group that can be converted to an aldehyde or ketone). To ensure that you understand the material in this chapter, you should review the meanings of the bold terms in the following summary and ask yourself how they relate to the topics in the chapter.Ĭarbohydrates, a large group of biological compounds containing carbon, hydrogen, and oxygen atoms, include sugars, starch, glycogen, and cellulose.
0 Comments
Leave a Reply. |
AuthorWrite something about yourself. No need to be fancy, just an overview. ArchivesCategories |