Medical brain notes 25

  Carbohydrates   Importance Carbohydrates are widely distributed in both plant and animal tissues. They are indispensible for living organisms and serve as skeletal structures in plants and also in insects and crustaceans. They occur as food reserves in the storage organs of plants and animals. They are the important source of energy required for the various metabolic activities of the living organisms. Definition Carbohydrates are defined as polyhydroxy aldehydes or ketones and are generally classified as follows. Classification Carbohydrates are generally classified into 4 major groups : ·             Monosaccharides ·             Disaccharides ·             Oligosaccharides and ·             Polysaccharides Monosaccharides These are carbohydrates that canno...

  Classification Carbohydrates are generally classified into 4 major groups : ·             Monosaccharides ·             Disaccharides ·             Oligosaccharides and ·             Polysaccharides Monosaccharides These are carbohydrates that cannot be hydrolysed into more simpler form. These are otherwise known as simple sugars. The general formula is C n (H 2 O) n . They may be subdivided into trioses, tetroses, pentoses and hexoses depending upon the number of carbon atoms they contain and also subdivided as aldoses and ketoses depending upon the presence of aldehyde or ketone groups (eg). Functions ·             Ribose is a structural element of nucleic acids and also of some coenzymes. ·   ...

  Proteins Definition Proteins may be defined as the high molecular weight polymers composed of α-amino acids united to one another by peptide linkage (-CO-NH-). Proteins are the major consitituents of all living organisms. They contain carbon, hydrogen, nitrogen, oxygen and sulphur.   Classification They are classified into 3 main groups. 1. Simple protein : These proteins on hydrolysis yield only α-amino acids. (eg). albumin, globulin 2. Conjugated protein : These are proteins composed of simple proteins combined with non-protein part called as prosthetic groups. They are further subdivided into: ·             Nucleo protein : Proteins present along with nucleic acids. (eg) Histones and Protamines. ·             Phosphoprotein : These are protein containing phosphoric acid (eg) casein of milk. ·             Glyco...