1. Early studies on the peptide(protein) structure 1.1 The peptide(o=c-n-h) bond was found to be shorter than the C-N bond in a simple amine and atoms attached are coplanar. 1.1.1 This was revealed by X-ray diffraction studies of amino acids and of simple dipeptides and tripeptides
1. Carbohydrates are aldehyde or ketone compounds with multiple hydroxyl groups or substances that can yield such compounds on hydrolysis(p. 293) 1.1 Carbohydrates are the most abundant biomolecules on earth and have multiple roles in all forms of life. 1.1.1 Carbohydrates serve as energy stores (e.g., starch in plants, glycogen in animals), fuels (e.g., glucose), and metabolic intermediates (e.., ATP, many coenzymes)
1. The good and bad sides of using triacylglycerols as an energy storage Highly reduced, more than twice as much energy as carbohydrates or proteins (~38 kJ/g vs ~18 kJ/g). Highly hydrophobic: does not raise osmolarity of cytosol, nor add extra weight; but must be emulsified before digestion and transported by special proteins in blood
1. Reduction(fixation)of N, into ammonia(NH3 or NH*) 2. Synthesis of the 20 amino acids 3. Synthesis of other biomolecules from amino acids 4. The de novo pathways for purine and pyrimidinebiosynthesis 5. The salvage pathways for purine and pyrimidine reuse
Radioisotope tracer experiments showed that the porphyrin(卟啉) ring of the heme groups in mammals are made from 8 Gly and 8 succinyl-COA (Glu in plants and bacteria). Deficiency of enzymes leading to heme biosynthesis cause diseases called porphyrias (The degradation of heme yields bilirubin, a linear tetrapyrrole derivative, and the typical pigments found
1. Reduction(fixation)of N, into ammonia(NH3 or NH*) 2. Synthesis of the 20 amino acids 3. Synthesis of other biomolecules from amino acids 4. The de novo pathways for purine and pyrimidinebiosynthesis 5. The salvage pathways for purine and pyrimidine reuse
