Wikibooks: An Introduction to Molecular Biology/Macromolecules and Cells

The term Molecular biology was first used by Warren Weaver in 1938. Molecular biology is the study of molecular underpinnings of the processes of replication transcription translation and cellular function. =Macromolecules= The term macromolecule was coined by Nobel laureate Hermann Staudinger in the 1920s although his first relevant publication on this field only mentioned high molecular compounds (in excess of 1000 atoms). At that time the phrase polymer as introduced by Berzelius in 1833 had a different meaning from that of today it simply was another form of isomerism such as an enzene or acetylene and had little to do with size. Some examples of organic macromolecules are bio polymers (carbohydrates proteins lipids nucleic acids) or polymers (plastics synthetic fiber and rubber). =Carbohydrates= A carbohydrate (kɑ bəˈhaɪdreɪt/) is an organic compound which has the empirical formula C m (H 2 O) n that is consists only of carbon hydrogen and oxygen with a hydrogen oxygen atom ratio of 2 1 (as in water). Carbohydrates can be viewed as hydrates of carbon hence their name. Structurally however it is more accurate to view them as polyhydroxy aldehydes and ketones. Historically nutritionists have classified carbohydrates as either simple or complex however the exact delineation of these categories is ambiguous. Today the term simple carbohydrate typically refers to monosaccharides and disaccharides and complex carbohydrate means polysaccharides (and oligosaccharides ). =a.Monosaccharides= Monosaccharides (from Greek monos single sacchar sugar) are the most basic units of biologically important carbohydrates. They are the simplest form of sugar and are usually colorless water soluble crystalline solids. Some monosaccharides have a sweet taste. Examples of monosaccharides include glucose (dextrose) fructose (levulose) galactose xylose and ribose. Monosaccharides are the building blocks of disaccharides such as sucrose and polysaccharides (such as cellulose and starch). Further each carbon atom that supports a ...