This chapter focuses on the first row of transition metals ranging from tin to copper. It clarifies how scandium and zinc are not transition metals due to their oxidation states and d subshells. The group has d-block elements with at least one stable ion that has a partially-filled d subshell. Transition metals showcase variable oxidation states. An acidic solution with a reductant can reduce a transition metal ion, while an alkaline solution with an oxidant could oxidize a transition metal. The stability of the high oxidation states can be significantly increased in alkaline solutions. The chapter also notes how transition metals are often used as catalysts.
Chapter
Transition Metals 2
Chapter
Many-electron atoms
This chapter focuses on many-electron atoms. The atomic orbitals developed for hydrogenic atoms are used to describe the electronic structure of many-electron atoms by using the building-up principle, a set of rules for predicting the order in which electrons occupy the available energy states, allowing for the repulsion between electrons and the Pauli exclusion principle. The building-up principle accounts for the structure of the periodic table and the variation through it of atomic radii, ionization energies, and electron affinities. One application of this material is to the discussion of an important inorganic contributor to life: zinc. The chapter also looks into the orbital approximation and the role of electron repulsion.
Chapter
Trace Elements
Samir Samman
This chapter studies the trace elements: zinc, copper, iodine, selenium, and fluoride. Zinc has a widespread role in cellular metabolism; it also plays a role in stabilizing macromolecules and cellular membranes, and it can function as a site-specific antioxidant. Copper also has diverse functions including in erythropoiesis, connective tissue synthesis (via lysyl oxidase), oxidative phosphorylation, thermogenesis, and superoxide dismutation. The efficiency of copper absorption increases in cases of deficiency or when dietary copper intake is low. Iodine functions as an integral part of the thyroid hormones and selenium exerts its biological effects as a constituent of selenoproteins, which are involved in a wide variety of processes in the body. Finally, fluoride acts to reduce dental caries. Other trace elements include chromium, manganese, and molybdenum.
Chapter
Minerals and trace elements
Ruan Elliott and Paul Sharp
This chapter discusses key minerals and trace elements essential to several important biochemical and physiological functions in the body. It primarily focuses on dietary sources of the various minerals and their homeostatic regulation in the body. Calcium and phosphorus are correlated due to their close interrelationship in maintaining bone health, while iron, zinc, iodine, and selenium hold essential roles in human metabolism. The chapter explains the major metabolic functions of the minerals and trace elements and the consequences of deficiency and excess of individual elements. It then looks into current methodologies used to assess the body status of minerals and trace elements and the basis of the current dietary recommendations for intakes of micronutrients.
Chapter
More metalloenzymes
This chapter explores more metalloenzymes, considering the enzymatic activity of zinc, cobalt, and molybdenum. Zinc is the second most abundant trace element in humans and is required as an integral component of over 100 enzymes in different species of all phyla. It can play an active catalytic role, generally as a strong Lewis acid, or it can act in regulatory or structural roles. The chapter then looks at trinuclear zinc constellations, vitamin B12, nitrogenases, and oxotransfer molybdoenzymes. Molybdenum is the only element from the second and third row transition metals that has been found to be essential to life. As well as functioning in nitrogenase, it has been found to be active in oxotransfer enzymes which catalyze the transfer of oxygen atoms to, or from, a substrate and are involved in carbon, nitrogen, and sulfur metabolism. The chapter also examines nickel enzymes.
Chapter
The biochemistry of zinc
This chapter takes a closer look at zinc, the most abundant transition metal in all living organisms next to iron. It provides examples for the following five main categories of proteins in which zinc attains a structural function and/or mediates catalytic processes: Enzymatic activity in hydrolytic processes; substrate activation for oxidative detoxification; interconversion between carbon dioxide and hydrogencarbonate; transcription of the genetic information contained in deoxyribonucleic acid (DNA) for protein synthesis; and demethylation — and thus repair — of DNA damaged by methylation. The chapter addresses questions on how zinc ions mediate the breakdown of proteins in our food, making available amino acids for resorption and thus usage in the synthesis of our body's own proteins; how ethanol is converted to acetaldehyde; how metabolically released carbon dioxide is processed for transport into the lungs; and how the small proteins called thioneins contribute to controlling zinc homeostasis in the body.
