Lecture Outline - Chapter 1

1.1 Elements and Atoms (p. 14, Fig. 1.2)
	1.	Atoms Have Structure (p. 14)
		a.	An atom is the smallest functional unit of an element.
		b.	Atoms are made up of protons (+) and neutrons (0) in the nucleus, with tiny electrons (-) in orbit about the nucleus. 
		c.	In an electrically neutral atom, the number of electrons equals the number of protons. Atoms are most stable when their outermost shell is filled with electrons, usually eight.
		d.	The atomic number of an atom equals its number of protons. The atomic weight is the number of protons plus neutrons.
	2. Isotopes Differ in Atomic Weight (p. 15, Figure 1.3)
		a.	Isotopes of an element have the same number of protons but differ in their number of neutrons.
		b.	Most isotopes are stable, but some are radioactive.
1.2 Molecules and Compounds (p. 16)
	1.	Opposite Charges Attract in Ionic Bonds (p. 16, Figs. 1.4, 1.5)
		a.	Atoms interact and bond with each other to form molecules.
		b.	Ions form when atoms give up or take on electrons. Ionic bonds form when an atom with a net negative charge is attracted to an atom with a net positive charge.
		c.	Ionic bonds are typical of inorganic molecules.
		d.	Many ions perform important functions in the body (Table 1.1).
	2.	Electrons Are Shared in Covalent Bonds (p. 18, Fig. 1.6)
		a.	In covalent bonds, two atoms share electrons. These bonds are typical of organic molecules.
		b.	More than one pair is shared in double and triple bonds. (p. 18)
1.3 Some Important Inorganic Molecules (p. 19)
	1.	Water Is a Polar Molecule (p. 19)
		a.	Water makes up 60 to 70% of the weight of most living creatures.
		b.	In water molecules, the larger oxygen atom exerts a greater pull on the electrons. The electrons are shared unevenly, and water is a polar molecule.
		c.	Due to the polarity, hydrogen bonds occur between oxygen atoms of one molecule and hydrogen atoms of adjacent water molecules (Fig. 1.7).
		d.	Because of the polarity and hydrogen bonding of water, water has characteristics that make life possible.
		e.	Water Has Unique Properties (p. 19, Fig. 1.8)
			i.	Water is the universal solvent.
			ii.	Water molecules are cohesive and fill vessels. 
			iii.	The temperature of liquid water rises and falls slowly.
			iv.	Water has a high heat of vaporization.
			v.	Frozen water is less dense than liquid water.
	2.	How Acids Differ from Bases (p. 21)
		a.	Acids (H+ Up) (p. 21)
			The polarity of water causes it to dissociate, forming H+ ions and OH- ions. Acids are molecules that release H+.
		b.	Bases (H+ Down) (p. 21)
			Bases are molecules that take up H+.
		c.	pH Scale (p. 22)
			The pH scale indicates relative amounts of H+ and OH- ions in solution.
	3.	Buffers Keep pH Steady (p. 22)
		Buffers, such as those found in the blood, help resist changes in pH by taking up excess H+ or OH- Ions.
		ECOLOGY FOCUS: The Harm Done by Acid Deposition (p. 23)
		i.	Burning fossil fuels produce sulfur dioxide and nitrogen oxides, which combine with water vapor to form acid rain. 
		ii.	Tall smokestacks carry emissions further, causing problems in distant areas.
		iii.	Acid rain kills wildlife in lakes and forest trees.
		iv.	Solutions include using alternative energy sources, scrubbers on smokestacks, and mass transit.
1.4 Molecules of Life (p. 24)
	1.	Organic molecules (macromolecules) are made of long chains of carbon.
	2.	Organic molecules form from building blocks called monomers.
1.5 Carbohydrates (p. 25) 
	1.	Carbohydrates Can Be Simple (p. 25 Fig. 1.17)
		The monomers of carbohydrates are the monosaccharides (glucose).
	2.	Starch and Glycogen Are Complex Carbohydrates (p. 25, Figs. 1.18-1.20)
		Two monosaccharides bonded together make a disaccharide; several bonded together constitute a polysaccharide (starch, glycogen).
	3.	Cellulose Provides Structural Support (p. 26, Fig. 1.21)
		a.	Cellulose is another polymer of glucose that provides structural support and protection for plant cells.
		b.	Humans cannot digest cellulose, but it contributes fiber.
1.6 Lipids (p. 27, Fig. 1.21)
	1.	Fats and Oils Are Similar (p. 27) 
		a.	Lipids are diverse in structure and do not dissolve in water.
		b.	Fats and oils are types of lipids known as triglycerides, made up of a molecule of glycerol and three fatty acids. 
	2.	Fatty Acids Are Saturated or Unsaturated (p. 27)
		a.	Saturated fatty acids, in animal fats, have hydrogen at every position along the carbon chain and no double bonds.
		b.	Unsaturated fats, in plant oils, have one or more double bonds. 
	3.	Soaps Are Emulsifiers (p. 27)
		Soaps are not lipids but help to emulsify lipids. Bile emulsifies fats in the digestive tract.
	4.	Phospholipids Have Polar Heads and Nonpolar Tails (p. 28, Fig. 1.23)
		a.	Phospholipids are similar to triglycerides except that a phosphate group replaces one of the fatty acids. Phospholipids thus have a polar "head" end and nonpolar fatty acid "tails."
		b.	Plasma membranes are made up of a double layer of phospholipids. 
	5.	Steroids Have Four Rings (p. 28, Fig. 1.24)
		a.	Steroids are made up of four fused carbon rings, with cholesterol as a precursor for many of them. The sex hormones are steroids.
		b.	Diets high in saturated fat and cholesterol lead to circulatory disorders.
1.7 Proteins (p. 29, Fig. 1.24)
	1.	Peptide Bonds Join Amino Acids (p. 30, Fig. 1.25)
		a.	Proteins serve a wide variety of functions in the body.
		b.	Amino acids are the monomers that comprise proteins. They are joined by covalent bonds called peptide bonds.
	2.	Proteins Have Levels of Organization (p. 30, Fig. 1.26)
		a.	Primary structure of a protein refers to its sequence of amino acids. 	Secondary structure is any twisting of the primary chain. Tertiary structure is any folding of the twisted chain. Quaternary structure results when several polypeptides are folded together.
		b.	The shape of a protein is important to its function. Proteins can be denatured, or unfolded and rendered nonfunctional.
	3.	Types of Proteins (p.32, Fig. 1.27)
		a.	Two types of proteins exist: Globular proteins and fibrous proteins. Enzymes and many non-enzyme molecules are globular. Fibrous proteins have a rod-like shape and a structural function, like myosin in muscle.
		b.	Keratin is a fibrous protein found in skin, nails, and hair.
		c.	Collagen and elastin are the fibrous proteins of tendons, ligaments, bone, and cartilage.
			HEALTH FOCUS: Nutrition Labels (p. 33, Fig. 1A)
			i.	Standardized nutrition labels are required for all packaged foods in the United States as of May 1994.
			ii.	Nutrient amounts are based on a diet of 2,500 Calories per day for men and 2,000 Calories per day for women.
			iii.	Fats should contribute less than 65 grams per day.
			iv.	A high-fiber, low-fat diet lowers risks of cancer and cardiovascular disease.
1.8 Nucleic Acids (p. 34, Fig. 1.28)
	1.	Nucleotides Join, Forming Nucleic Acids (p. 34, Fig. 1.29)
		a.	Genes are composed of DNA, and RNA functions in protein synthesis.
		b.	Nucleic acids are built from polymers of nucleotides.
	2.	ATP Is a Carrier of Energy (p. 35, Fig. 1.30)
		ATP is a nucleotide that serves as an energy carrier in cells.