1. The important properties of water are attributable to its polar covalent bonds and to its V shape. These properties make water a good solvent, transport medium, coolant, lubricant, and ready participant in chemical reactions.

2. Solvency (p. 78)

3. Cohesion (p. 78)

4. Thermal Stability (p. 79)

5. Chemical Reactivity (p. 79)

1. Minerals are inorganic elements passed to us through the food chain and make up about 4% of the mass of the human body.

2. Most of the mineral content of the body is calcium and phosphorus and contribute to the structure of body parts (i.e. bone).

3. Minerals also take part in many metabolic reactions as cofactors or electrolytes.

1. Carbon dioxide and oxygen are the two most important gases in the body.

2. Certain gases are also used as chemical messengers, like nitric oxide and carbon monoxide.

1. Carbon is used extensively by organisms. It reacts readily to form four covalent bonds, giving it the ability to form long chains.

1. A functional group is a small cluster of atoms that determines many of the properties of the organic molecule.

1. Large organic molecules are called macromolecules. These are mostly polymers, repeating series of subunits (building blocks) called monomers.

2. Joining monomers form a polymer is called polymerization. This occurs by dehydration synthesis.

3. Breaking polymers apart requires the addition of water through hydrolysis.

1. A carbohydrate is a hydrophilic organic molecule with a 2:1 ratio of hydrogen to oxygen.

2. The simple sugars are the monosaccharides that serve as the monomers for polysaccharides.

3. Glucose, fructose, and galactose are the three monosaccharides of primary importance.

1. Two monosaccharides joined together become a disaccharide. Table sugar, sucrose, is made up of glucose + fructose.

2. The C-O-C bonds that hold the disaccharides together are called glycosidic bonds.

1. Polymers of glucose are called polysaccharides.

2. The polysaccharide cellulose gives plant cell walls strength and gives roughage to the human diet.

3. Starch is a polysaccharide that serves to store energy for plants.

4. Glycogen is the polysaccharide form animals and humans use to store energy.

1. Carbohydrates primarily serve as a source of energy.

2. Carbohydrates are also often conjugated with proteins and lipids, forming glycoproteins and glycolipids (components of the glycocalyx of cells). Glycoproteins are also a major component of mucus.

3. Proteoglycans (mucopolysaccharides) hold cells and tissues together, lubricate joints, are a component of cartilage, and have other functions.

1. A lipid is a hydrophobic organic molecule, mostly composed of C, H, and O, with a high ratio of H to O. Lipids are less oxidized than carbohydrates.

2. Fatty acids are one type of lipid, and are a chain of 4 to 24 carbon atoms, with a carboxyl group at one end and a methyl group at the other.

3. Fatty acids are saturated (with a hydrogen at every position along the carbon chain) or unsaturated (missing a carbon, and with a double bond).

4. Polyunsaturated fatty acids have multiple C=C bonds.

1. A triglyceride is a neutral fat made up of three fatty acids bound to a molecule of glycerol.

2. Dietary triglycerides take the form of oils (from plants) and animal fat.

3. In the body, triglycerides store energy in adipose tissue, and insulate and cushion.

1. Phospholipids contain two fatty acids and a phosphate group.

2. They have a polar hydrophilic region (phosphate group end) and hydrophilic fatty acid tails (hydrophobic area).

3. They serve as the structural foundation of cell membranes.

1. Prostaglandins are fatty acids modified into a ring structure.

2. They are produced in almost all types of tissue, and serve as intercellular messengers.

1. Steroids are lipids with complex ring structures.

2. Examples include cholesterol and steroids formed from it.

1. A protein is a polymer of amino acids.

2. An amino acid has a carboxyl end and an amino end, as well as a variable R group.

3. Twenty kinds of amino acids are used in protein structure.

1. Two or more amino acids is a peptide.

2. A peptide bond is formed between the amino group of one amino acid and the carboxyl group of the next.

3. Peptides vary according to size: dipeptides, tripeptides, polypeptides.

1. Primary structure refers to the order of the amino acids in the peptide.

2. Secondary structure is a coiled or folded shape held together by hydrogen bonds.

3. Tertiary structure is formed by further bending and folding.

4. Quaternary structure occurs between two or more polypeptide chains.

1. Protein conformation refers to its overall shape. It cannot function properly if the shape is altered.

2. Denaturing a protein using heat or changes in pH causes it to unwind and destroys it.

1. Conjugated proteins have a non-amino acid prosthetic group bound to them, such as hemoglobin.

1. Protein functions include serving as structural components, for catalysis as enzymes, for communication, to provide membrane transport, in cell recognition and protection, and for movement.

1. Enzymes are proteins that function as catalysts.

2. Enzymes serve to lower the energy of activation in a chemical reaction, causing it to proceed.

3. Enzymes are not altered from acting as catalysts.

1. Enzymes are named for the substrate upon which they act, adding the suffix -ase to the substrate name.

1. Portions of enzyme molecules serve as active sites where substrate molecules attach.

2. Enzymes are specific for their substrates (enzyme-substrate specificity).

3. Enzymes adjust shape slightly to accommodate the substrate (induced-fit), forming an enzyme-substrate complex.

1. Enzymes are temperature and pH sensitive, since slight changes can disrupt hydrogen bonds holding the molecule in its proper conformation.

1. Many enzymes require nonprotein cofactors to function properly.

1. Metabolic pathways require a sequence of enzymes to catalyze each reaction in turn.

2. Pathways can be limited by allosteric inhibition. Enzymes can be reversibly inhibited.

1. Many enzymes work in conjunction with organic coenzymes.

1. Adenosine triphosphate (ATP) is the universal energy-carrying molecule. It is continually regenerated.

2. ATP consists of a double carbon-nitrogen ring (adenine), a five-carbon sugar (ribose), and a chain of three phosphate groups.

3. Most energy transfers involve removing the terminal phosphate group, employing ATPases.

4. ATP is regenerated via phosphorylation.

1. The oxidation of glucose is the primary source of energy to synthesize ATP.

2. The first stage of oxidation is glycolysis, in which glucose is split into two three-carbon molecules of pyruvic acid.

3. If no oxygen is available, pyruvate enters anaerobic fermentation, a more inefficient pathway.

4. If oxygen is available, aerobic respiration occurs within the mitochondria.

1. Guanosine triphosphate (GTP) is another energy-transferring molecule.

2. Nucleotides, which are the monomers of DNA and RNA, have a structure similar to that of ATP.

CHAPTER ESSAY: Synthetic Steroids and Artificial Athletes (p. 102; Fig. E.1)