AP 1 CHAPTER 2 LECTURE REVISED NOTES FOR EXAM PREPARATION
Biochemistry
The study of the molecules that compose living organisms
Element
simplest form of matter to have unique chemical properties
Atomic number of an element
number of protons in its nucleus
Periodic table
*Elements arranged by atomic number
*Elements represented by one- or two-letter symbols
Minerals
*inorganic elements extracted from soil by plants and passed up food chain to humans
~Ca, P, Cl, Mg, K, Na, and S
~Constitute about 4% of body weight
~Important for body structure (Ca crystals in teeth, bones, etc.) ~Important for enzymes'
functions
Electrolytes
*substances that ionize in water and form solutions capable of conducting electric current
*mineral salts needed for nerve and muscle function
*Electrolyte importance ~Chemical reactivity, osmotic effects, electrical excitability of nerve and
muscle
~Electrolyte balance is one of the most important considerations in patient care (imbalances
can lead to coma or cardiac arrest)
Nucleus
center of atom
Protons:
single (+) charge; mass = 1 atomic mass unit (amu)
Neutrons
no charge; mass = 1 amu
,Atomic mass
is approximately equal to total number of protons and neutrons
Electrons
in concentric clouds surrounding nucleus Electrons: single (-) charge, very low mass
~An atom is electrically neutral, as number of electrons equals number of protons
~Valence electrons orbit in the outermost shell and determine chemical bonding properties of
an atom
Isotopes
*varieties of an element that differ only in the number of neutrons
~Extra neutrons increase atomic weight
~Isotopes of an element are chemically similar because they have the same number of valence
electrons
Atomic weight (relative atomic mass)
of an element accounts for the fact that an element is a mixture of isotopes
Ion
charged particle (atom or molecule) with unequal number of protons and electron
Ionization
transfer of electrons from one atom to another
Anion
particle that gains electron(s) (net negative charge)
Cation
particle that loses electron(s) (net positive charge)
Ions with opposite charges are attracted to each other
Free radicals
*short-lived particles with an unusual number of electrons
~Produced by normal metabolic reactions, radiation, certain chemicals
~Trigger reactions that destroy molecules, and can cause cancer, death of heart tissue, and
aging
Antioxidants
, *Chemicals that neutralize free radicals
Superoxide dismutase (SOD) is an antioxidant enzyme in the body Selenium, vitamin E, vitamin
C, and carotenoids are antioxidants obtained through the diet
Molecule
chemical particle composed of two or more atoms united by a chemical bond
Compound
molecule composed of two or more different elements
Molecular formula
identifies constituent elements and how many atoms of each are present
Structural formula
identifies location of each atom
Isomers
molecules with identical molecular formulae but different arrangement of their atoms
Chemical bonds
*hold atoms together within a molecule or attract one molecule to another
*Most important types of chemical bonds: ionic bonds, covalent bonds, hydrogen bonds, van
der Walls forces
Ionic bonds
Attractions between anions and cations (example, NaCl) Electrons donated from one atom to
another *Easily broken by water
Nonpolar bond
electrons shared equally (strongest bond)
Polar bond
electrons shared unequally (spend more time near oxygen)
Hydrogen bond
*a weak attraction between a slightly positive hydrogen atom in one molecule and a slightly
negative oxygen or nitrogen atom in another
~Water molecules are attracted to each other by hydrogen bonds
Biochemistry
The study of the molecules that compose living organisms
Element
simplest form of matter to have unique chemical properties
Atomic number of an element
number of protons in its nucleus
Periodic table
*Elements arranged by atomic number
*Elements represented by one- or two-letter symbols
Minerals
*inorganic elements extracted from soil by plants and passed up food chain to humans
~Ca, P, Cl, Mg, K, Na, and S
~Constitute about 4% of body weight
~Important for body structure (Ca crystals in teeth, bones, etc.) ~Important for enzymes'
functions
Electrolytes
*substances that ionize in water and form solutions capable of conducting electric current
*mineral salts needed for nerve and muscle function
*Electrolyte importance ~Chemical reactivity, osmotic effects, electrical excitability of nerve and
muscle
~Electrolyte balance is one of the most important considerations in patient care (imbalances
can lead to coma or cardiac arrest)
Nucleus
center of atom
Protons:
single (+) charge; mass = 1 atomic mass unit (amu)
Neutrons
no charge; mass = 1 amu
,Atomic mass
is approximately equal to total number of protons and neutrons
Electrons
in concentric clouds surrounding nucleus Electrons: single (-) charge, very low mass
~An atom is electrically neutral, as number of electrons equals number of protons
~Valence electrons orbit in the outermost shell and determine chemical bonding properties of
an atom
Isotopes
*varieties of an element that differ only in the number of neutrons
~Extra neutrons increase atomic weight
~Isotopes of an element are chemically similar because they have the same number of valence
electrons
Atomic weight (relative atomic mass)
of an element accounts for the fact that an element is a mixture of isotopes
Ion
charged particle (atom or molecule) with unequal number of protons and electron
Ionization
transfer of electrons from one atom to another
Anion
particle that gains electron(s) (net negative charge)
Cation
particle that loses electron(s) (net positive charge)
Ions with opposite charges are attracted to each other
Free radicals
*short-lived particles with an unusual number of electrons
~Produced by normal metabolic reactions, radiation, certain chemicals
~Trigger reactions that destroy molecules, and can cause cancer, death of heart tissue, and
aging
Antioxidants
, *Chemicals that neutralize free radicals
Superoxide dismutase (SOD) is an antioxidant enzyme in the body Selenium, vitamin E, vitamin
C, and carotenoids are antioxidants obtained through the diet
Molecule
chemical particle composed of two or more atoms united by a chemical bond
Compound
molecule composed of two or more different elements
Molecular formula
identifies constituent elements and how many atoms of each are present
Structural formula
identifies location of each atom
Isomers
molecules with identical molecular formulae but different arrangement of their atoms
Chemical bonds
*hold atoms together within a molecule or attract one molecule to another
*Most important types of chemical bonds: ionic bonds, covalent bonds, hydrogen bonds, van
der Walls forces
Ionic bonds
Attractions between anions and cations (example, NaCl) Electrons donated from one atom to
another *Easily broken by water
Nonpolar bond
electrons shared equally (strongest bond)
Polar bond
electrons shared unequally (spend more time near oxygen)
Hydrogen bond
*a weak attraction between a slightly positive hydrogen atom in one molecule and a slightly
negative oxygen or nitrogen atom in another
~Water molecules are attracted to each other by hydrogen bonds
