Protein or the physical region of the protein that participates in chemical catalysis. In solution proteins also undergo variation in structure through thermal vibration and the collision with other molecules. Proteins can be informally divided into three main classes, which correlate with typical tertiary structures: globular proteins, fibrous proteins, and membrane proteins. Almost all globular proteins are soluble and many are enzymes. Fibrous proteins are often structural, such as collagen, the major component of connective tissue, or keratin, the protein component of hair and nails. Membrane proteins often serve as receptors or provide channels for polar or charged molecules to pass
Black Is the Color (of My True Love's Hair) Black Is the Color (of My True Love's Hair) "Black Is the Color (of My True Love's Hair)" (Roud 3103) is a traditional folk song first known in the US in the Appalachian Mountains but originating from Scotland, as attributed to the reference to the Clyde in the song's lyrics. The musicologist Alan Lomax supported this Scottish origin, saying that the song was an American "re-make of British materials." Many different versions of this song exist, some addressed to females and others addressed to males, as well as other differences: These words are set to two distinct melodies, one of