Chapter 2 Outline

II. Chemistry Comes Alive
1) Basic Chemistry
a) Matter and Energy
i) Matter – anything that occupies space and has mass (weight)
ii) Energy – the ability to do work
• Various Forms:
(a) Chemical (food)
(b) Electrical (light)
(c) Mechanical (ei. Wind-up flashlights)
(d) Radiant (sun)
(e) Others…
b) Composition of Matter: Atoms and Elements
i) Basic Terms
• Elements – fundamental units of matter
(a) 96% of the body is made from the four elements:
o Carbon (C)
o Oxygen (O)
o Hydrogen (H)
o Nitrogen (N)
• Atoms – building blocks of elements
• Atomic symbols

ii) Atomic structure (See Figs. 2.1& 2.2)
• Nucleus
(a) Inside
o Protons (p+) – positive charge
o Neutrons (n) – neutral charge
(b) Outside
o Electrons (e-) – negative charge
• Isotopes

iii) Major elements of the human body (See Table 2.1)
iv) Identification of elements
• Atomic number – the number of protons
• Mass number – sum of protons and neutrons
• Atomic weight – reflects the different isotopes
• Isotopes – have the same number of protons, vary in the number of neutrons
• Radioactivity – process of spontaneous atomic decay
(a) Radioisotope:
o Heavy isotope
o Tends to be unstable
o Decomposes to more stable isotope

c) Molecules and Mixtures
i) Molecules – two or more like atoms combined chemically
ii) Compounds – two or more different atoms combined chemically
iii) Mixtures

d) Chemical bonds – atoms are united by these
i) Atoms dissociate from other atoms when chemical bonds are broken
ii) The role of electrons in chemical bonding
• Electron shells – energy levels occupied by electrons, elections closest to the nucleus are most strongly attracted
(a) Each shell has distinct properties:
o The number of electrons has an upper limit
o Shells closest to the nucleus fill first
• Energy levels
• Bonding involves interactions between electrons in the outer (valence shell)
• Filling of electron shells
(a) Valence shell – if full, do not form bonds
(b) Rule of eight = rule of octet
• Inert elements (See Fig. 2.5a)
(a) Atoms are stable (inert elements) when the outer most shell (valence shell) is complete
(b) How to fill the atom’s shells:
Shell 1 can hold a max of 2 electrons
Shell 2 can hold a max of 8 electrons
Shell 3 can hold a max of 18
• Active elements
(a) Valence shells are not full and are unstable
(b) Tend to gain, lose, or share electrons
o Allow for bond formation, which produces stable valence

iii) Types of chemical bonds
• Ionic bonds (See Figure 2.6) – forms when electrons are completely transferred from one atom to another
(a) Transfer of electrons
(b) Ions – charged particles
o Anions are negative
o Cations are positive
o Either donate or accept electrons
• Covalent bonds (See Fig. 2.7)
(a) Atoms become stable through shared electrons
(b) Single covalent bonds share one pair of electrons
(c) Double covalent bonds share two pairs of electrons
(d) Covalently bonded molecules:
o Some are non-polar
 Electrically neutral as a molecule
o Some are polar
(e) Have a positive and negative side
• Hydrogen bonds:
(a) Weak chemical bonds
(b) Hydrogen is attracted to the negative portion of polar molecule
(c) Provides attraction between molecules, like a magnetic force

iv) Types
• Synthesis or anabolic reactions (endergonic)
(a) A + B AB
(b) Atoms or molecules combine
(c) Energy is absorbed for bond formation
• Decomposition or catabolic reactions (exergonic)
(a) AB A + B
(b) Molecule is broken down
(c) Chemical energy is released
• Exchange or displacement reactions
(a) AB + C  AC + B
(b) Involves both synthesis and decomposition reactions
(c) Switch is made between molecule parts and different molecules are made

v) Reversibility of chemical reactions
vi) Rate of chemical reactions
(1) Temperature
(2) Particle Size
(3) Concentration
(4) Catalysts/Enzymes

2) Biochemistry – essentials for life
a) Organic compounds
i) Contains carbon
ii) Most are covalently bonded
iii) Example: C6H12O6 (glucose)
b) Inorganic compounds
i) Lack carbon
ii) Tend to be simpler compounds
iii) Example: H2O (water)
iv) Important Inorganic Compounds
• Water (Figure 2.8 &2.9): most abundant inorganic compound
(a) Vital properties:
o High heat capacity
o Polarity/solvent properties
o Chemical reactivity
o Cushioning
• Salts (See Fig. 2.12)
(a) Vital properties:
o easily dissociate into ions in the presence of water
o Vital to many body functions
o Include electrolytes which conduct electrical currents
• Acids and bases (See Fig. 2.13)
(a) Acids – release hydrogen ions (H+)
o Are proton donors
(b) Bases – release hydroxyl ions (OH-)
o Are proton acceptors
(c) pH (Fig. 2.12)
o Acidic – pH below 7
o Basic – pH above 7
o Neutral – pH is 7
o Neutralization reaction
 Acids and bases react to form a water and a salt
o Buffers – chemicals that can regulate pH change

c) Important Organic compounds
i) Carbohydrates (See Figs. 2.13)
• Contains carbon, hydrogen, and oxygen.
• Includes sugars and starches
(a) Classified according to size:
o Monosaccharides - simple sugars
 Body uses this to digest
o Disaccharides – two simple sugars joined by dehydration synthesis
o Polysaccharides – long-branching chains of linked simple sugars

ii) Lipids (See Fig. 2.15) – fat
• Contains carbon, hydrogen, and oxygen
(a) Carbon and hydrogen outnumber oxygen
• Insoluble in water
• Common lipids in the human body:
(a) Neutral fats (triglycerides):
o Found in fat deposits
o Composed of fatty acids and glycerol
o Source of stored energy
(b) Phospholipids
o Form cell membranes
(c) Steroids
o Includes cholesterol, bile salts, vitamin D, and some hormones

iii) Proteins (See Fig. 2.16 & 2.17)
• Made of Amino acids
• Contains carbon, oxygen, hydrogen, nitrogen, and sometimes sulfur
• Accounts for over half of the body’s organic matter
• Provides for construction materials for body tissues
• Play a vital role in cell functions
• Act as enzymes, hormones, and anitbodies
• Structural levels of proteins
(a) Primary structure
(b) Secondary structure
(c) Tertiary structure
(d) Quaternary structure

• Fibrous versus Globular proteins
• Protein denaturation
• Enzymes
(a) Characteristics
(b) Mechanism of actions (See Fig. 2.18)

iv) Nucleic acids (See Fig. 2.19): provide blueprint of life
• Nucleotides – makes DNA and RNA
(a) Nucleotide bases:
o A = Adenine
o G = Guadnin
o C = Cytosine
o T = Thymine
o U = Uracil
(b) Sugar
o Ribose (RNA)
o Deoxyribose (DNA)
(c) Phosphate group
• Types
(a) Deoxyribonucleic acid DNA
(b) Ribonucleic acid RNA

v) Adenosine triphosphate ATP (See Figs. 2.20 & 2.21) = energy
• Chemical energy used by all cells
• Energy is released by breaking high energy phosphate bonds
• ATP is replenished by oxidation of food fuels