This chapter discusses carbohydrates, which are an important source of rapid energy production for living cells,the structural building blocks of cells, and the components of numerous metabolic pathways. The chapter refers to sugar polymers linked to proteins and lipids which, it states, are now recognized as a high-density coding system. Their vast structural diversity is exploited by living organisms to produce the immense informational capacity required for living processes. The chapter describes the structures and chemistry of typical carbohydrate molecules found in living organisms. Carbohydrates are the most abundant biomolecules in nature and are a direct link between solar energy and the chemical bond energy of living organisms.
Chapter
Carbohydrates
Chapter
Carbohydrate Metabolism
This chapter reviews the crucial roles carbohydrates play in the metabolic processes of living organisms as they serve as energy sources and structural elements in living cells. It looks at the role of carbohydrates in energy production, focusing on its synthesis, degradation, and storage as the monosaccharide glucose is a prominent energy source in almost all living cells. The term metabolism is used to describe the thousands of enzyme-catalysed biochemical reactions that sustain life in living organisms. The chapter analyses how biochemical reactions are spatially and temporally organised into complex, interconnected networks. It classifies all biochemical reaction pathways into three major categories: signal transduction pathways, genetic regulatory pathways, and core metabolic pathways.
Book
Richard Bowater, Laura Bowater, and Tom Husband
Biochemistry introduces this topic with an examination of carbohydrates, asking why we need them in our lives. It then looks at the building blocks of a cell, namely, lipids and proteins. Nucleotides and nucleic acids are the next topic to be covered. The text moves on to consider metabolism. It asks what it means and how energy is transformed. Other questions asked include: how is a metabolic balance maintained? How can we solve the problems of the future with natural products? Finally, the text looks at bioenergy and the environment.
Chapter
Carbohydrates: Why Life is Sweet
This chapter describes the chemistry that underpins biomolecules, before considering the variety and flexibility of carbohydrates and their roles in living organisms. All biological cells are made up of common building blocks, or biomolecules, which carry out similar types of biochemical reactions. There are four types of these fundamental biomolecules: carbohydrates, proteins, lipids, and nucleic acids. Carbohydrates are the most abundant biomolecules on Earth and are characterized by great chemical and structural diversity. They are classified by size as monosaccharides, disaccharides, oligosaccharides, or polysaccharides. Carbohydrates are found in plant cell walls, the connective tissues of animals, and exoskeletons, and they are essential to the function of some proteins and cell-to-cell communication. They are also important fuels and energy stores, underpinning energy-yielding pathways in non-photosynthetic organisms.
Book
Trudy McKee and James R. McKee
Biochemistry begins with an introduction to the topic. Discussions covered include living cells, the importance of water to life, energy, and amino acids, peptides, and proteins. The book also contains chapters on carbohydrates, carbohydrate metabolism, aerobic metabolism, and lipids and membranes. The text goes on to examine photosynthesis, nitrogen metabolism, nucleic acids, and genes. Finally, it looks at protein synthesis.
Chapter
Biological macromolecules: the infrastructure of life
This chapter studies some of the key biological macromolecules that make life happen: amino acids and proteins, nucleic acids, carbohydrates, and lipids. Amino acids join together to form polymers named polypeptides. The structure of proteins is built up over four levels of hierarchy: primary, secondary, tertiary, and quaternary. Protein structure is stabilized by both non-covalent interactions (including hydrogen bonds and hydrophobic interactions) and covalent bonding, including disulfide bonds. The chapter also describes the two key natural nucleic acids, deoxyribonucleic acid (DNA) and ribonucleic acid (RNA). Nucleic acids are polymers of nucleotides. The chapter then considers the three main classes of carbohydrate (sugar)—monosaccharides, disaccharides, and polysaccharides. It also looks at the three most important types of lipid: steroids, triacylglycerols, and the glycerophospholipids.
Chapter
Molecules
This chapter discusses molecules, starting with an explanation of bonds. Living organisms are made of up of organic molecules consisting mainly, though not exclusively, of carbon (C), hydrogen (H), oxygen (O), nitrogen (N), and sulfur (S). These are held together by bonds which vary in strength and length. The chapter then looks at covalent bonds, ionic or electrostatic bonds, dipole–dipole interactions, hydrogen bonds, van der Waals forces, and the hydrophobic effect. It also considers proteins, lipids, and carbohydrates, before looking at DNA (deoxyribonucleic acid) and RNA (ribonucleic acid). DNA is the genetic material of most living organisms and it exists as a very long filamentous double helix. Meanwhile, RNA s a single-stranded polymer of ribonucleotides linked by phosphodiester bonds.
