Much of our understanding of metabolic pathways has resulted from the use of chemical and isotopic labels. In this experiment, a heavy isotope of carbon, [superscript 13]C, is used to label the product of the well-known RuBisCO enzymatic reaction. This is a key reaction in photosynthesis that converts inorganic carbon to organic carbon; a process…

Discusses the biochemical mechanisms related to photosynthesis. Describes a water-oxidizing clock generating a molecule of oxygen with every four ticks. Lists four references. (YP)

Topics in this discussion of photorespiration (light-dependent oxygen consumption and carbon dioxide evolution from leaves) include: (1) the biochemistry of photorespiration; (2) ribulose biphosphate carboxylase and glycollate synthesis; (3) metabolism of glycollate; (4) plants lacking photorespiratory systems; and (5) advantages of…

Discusses the diversity and dynamic nature of the chemical components of postharvest crops. Also discusses the role of respiration and genetic control in chemical transformations leading to desirable and undesirable changes in the quality of edible plants after harvest. The role of enzymes in producing these changes is considered. (JN)