Download THE CHEMISTRY OF LIFE – CH

THE CHEMISTRY OF LIFE – CH. 6
 Element – a substance that can’t be broken down into
simpler substances.
 Atom – smallest particle of an element that has the
characteristics of that element
 Nucleus – contains protons (positively charged) and
neutrons (no charge).
 Electrons – negatively charged particles that surround the
nucleus and participate in chemical reactions (bonding).
 Isotopes – atoms of the same element which contain
different numbers of neutrons.
 Compound – composed of two or more atoms of different
elements.
 Covalent bond – bonds between atoms in which electrons
are shared. Most compounds in organisms are formed by
covalent bonds. (sugars, fats, proteins, water)
 Molecule – group of atoms held together by a covalent bond.
 Ionic bond – atoms held together by the attractive force
between ions. Ions are atoms which have gained or lost
electrons and are therefore charged. These are less abundant
in living things.
 Metabolism – all the chemical reactions that occur in
organisms.
 Chemical reaction – is the process by which one or more
substances change to produce one or more different
substances.
REACTANTS
PRODUCTS
(original substances) → (substances created)
 Word Equation:
Glucose and oxygen react to form (produce) carbon dioxide and water.
 Formula Equation:
C6H12O6 + O2→ CO2 + H2O
All living things are chemical factories driven by
chemical reactions.
Catalyst – can help speed up a chemical reaction.
o Enzymes – biological catalysts which are proteins.
o Enzymes are essential to life.
o Enzymes are specific to one reaction. (i.e. amylase found in
saliva)
o Enzymes have active sites where the reactants (called
substrates) bind.
 Acid – any substance that forms hydrogen ions when
dissolved in water.
 Base – any substance that forms hydroxide ions when
dissolved in water.
pH scale:
1_______________________ 7 ____________________14
acidic
neutral
base
WATER IS POLAR
 Polar molecules have an unequal distribution of charge (a
positive end and a negative end).
 attract ions
 attract other polar molecules (water molecules attract other
water molecules)-- negative end of one attracts positive end
of another
 water can dissolve many ionic (salt) and polar compounds
(sugar)
 capillary action – creep up small tubes (plants)
 Hydrogen bonds are important to organisms because they
hold many biomolecules (proteins, carbohydrates) together.
 Organic Compounds (compounds made with carbon):
 are macromolecules (or polymers) – large molecules
made when smaller molecules bond together to form chains.
1. Carbohydrates – provide energy. Made of C, H and O
ex. sugars – glucose, fructose, sucrose, starch, cellulose (cell
walls of plants)
2. Lipids (fats) – energy storage. Made of C, H and small
amount of O. ex. fats, oils, waxes, steroids, phospholipids.
o Saturated fatty acids – all single C to C bonds, so C cannot
bond with other hydrogen atoms.
o Unsaturated fatty acids – Contains a double bond so C can
bond with other hydrogen atoms.
o Polyunsaturated fatty acids – more than one double bond
3. Proteins – provide structure for tissues and organs and carry out
metabolism. Made of C, H, O, N and sometimes S. ex. amino
acids, enzymes
4. Nucleic Acids – stores cellular information in the form of a code.
Made of nucleotides - ex. DNA, RNA