Chapter 2 Flashcards
neutrons
no charge
protons
positive charge
electrons
negative charge
covalent bonds
valence electrons are shared, low electronegativity difference
molecule
2 or more atoms held together by covalent bonds
electronegativity
attraction for electrons
nonpolar covalent bond
electrons are shared equally
polar covalent bond
one atom is more electronegative, and atoms do not share electrons equally, creating partial charges
ionic bonds
electrons are transferred, forms cation (positive) and anion (negative)
hydrogen bonds
weak bonds created by hydrogen’s charge attraction to oxygen in separate water molecules
acidic solutions
pH less than 7
basic solutions
pH greater than 7
carbon
forms large, complex, and varied molecules, and organic compounds
dehydration reaction
two monomers bond together through the loss of a water molecule
hydrolysis
polymers are disassembled by the addition of a water molecule
enzymes
speed up chemical reactions
monosaccharides
molecular formulas that are multiples of CH2O
lipids
hydrophobic because consist mostly of hydrocarbons (which form nonpolar covalent bonds) and thus do not form true polymers
saturated fats
single bonds, saturated by hydrogens, solid at room temperature; most animal fats
unsaturated fats
contains double bonds, can’t pack as closely together, fewer hydrogens, liquid at room temperature; usually plant and fish fats
phospholipid
major constituents of cell membranes; two fatty acids (hydrophobic) and a phosphate group (hydrophilic) attached to glycerol
proteins
more than 50% of dry mass of most cells, made of amino acids, functions include defense, storage, transport, cellular communication, movement, and structural support
primary structure
linear chain of amino acids
secondary structure
regions stabilized by hydrogen bonds between atoms of the polypeptide backbone
