Download BIOCHEMISTRY

BIOCHEMISTRY
CHEMISTRY OF LIFE
• Elements: simplest form of a
substance - cannot be broken down
any further without changing what it is
• Atom: the actual basic unit composed of protons, neutrons, and
electrons
THE ATOM
• Just like cells are the basic unit of life, the
ATOM is the basic unit of matter.
• They are very small. If placed side by side
one million would stretch a distance of 1cm.
• The atom is made up of 3 particles.
Particle
Charge
PROTON
+
NEUTRON
NEUTRAL
ELECTRON
-
• Electrons are not present within the atom,
instead THEY REVOLVE AROUND THE
NUCELUS OF THE ATOM & FORM THE
ELECTRON CLOUD
• Draw a helium atom. Indicate where the
protons, neutrons and electrons are.
NEUTRONS
-
ELECTRONS
PROTONS
+
ATOMIC # = 2 (PROTONS)
+
-
ATOMIC MASS = 4
(PROTONS &
NEUTRONS)
COMPOUNDS
• a substance formed by the chemical
combination of 2 or more elements in definite
proportions
– Ex: water, salt, glucose, carbon dioxide
TWO TYPES OF COMPOUNDS
•
Organic - Contain C, H, and O in some
ratio (usually referred to as chemicals of
life)
–
•
Carbohydrates, Proteins, Lipids, Nucleic Acids
Inorganic - usually "support" life - no
specific ratio of C, H, and O
–
Water (H2O), Carbon Dioxide (CO2)
CHEMICAL BONDS
• Chemical bonds hold the atoms in a
molecule together.
• There are 2 types of chemical bonds
IONIC and COVALENT
MIXTURES
• Water is not always pure. It is often found as
part of a mixture.
• A mixture is a material composed of TWO OR
MORE ELEMENTS OR COMPOUNDS THAT
ARE PHYSICALLY MIXED
– Ex: salt & pepper mixed, sugar and sand – can be
easily separated
SOLUTION
Two parts:
• SOLUTE – SUBSTANCE THAT IS BEING
DISSOLVED (SUGAR / SALT)
• SOLVENT - the substance in which the solute
dissolves
• Materials that do not dissolve are known as
SUSPENSIONS.
– Blood is the most common example of a
suspension.
– Cells & other particles remain in suspension.
ACIDS & BASES
•
Acids: always (almost) begin with "H" because
of the excess of H+ ions (hydrogen)
–
Ex: lemon juice (6), stomach acid (1.5), acid rain
(4.5), normal rain (6)
Facts about Acids
• Acids turn litmus paper BLUE and usually
taste SOUR.
• You eat acids daily (coffee, vinegar, soda,
spicy foods, etc…)
ACIDS & BASES
• Bases: always (almost) end with -OH because
of the excess of hydroxide ions (Oxygen &
Hydrogen)
– EX: oven cleaner, bleach, ammonia, sea water,
blood, pure water
Facts about Bases
• Bases turn litmus BLUE.
• Bases usually feel SLIPPERY to touch and taste
BITTER.
pH SCALE
• measures degree of
substance alkalinity or
acidity
• Ranges from 0 to 14
• 0 – 5 strong acid
• 6-7 neutral
• 8-14 strong base
• The goal of the body is to maintain
HOMEOSTASIS (neutrality) – to do this when
pH is concerned, we add weak acids & bases to
prevent sharp changes in pH.
• These are called BUFFERS
And now for the
Biochemistry portion of
things….
BIOCHEMISTRY is the
chemistry of living
organisms and of vital
processes.
CARBOHYDRATES
• Living things use carbohydrates as a key source
of ENERGY!
• Plants use carbohydrates for structure
(CELLULOSE)
– include sugars and complex carbohydrates
(starches)
– contain the elements carbon, hydrogen, and oxygen
(the hydrogen is in a 2:1 ratio to oxygen)
Lipids (Fats)
• Fats, oils, waxes, steroids
• Chiefly function in energy storage, protection,
and insulation
• Contain carbon, hydrogen, and oxygen but the
H:O is not in a 2:1 ratio
• Tend to be large molecules -- an example of a
neutral lipid is below
• Neutral lipids are formed from the union of one
glycerol molecule and 3 fatty acids
• 3 fatty acids + glycerol ----> neutral fat (lipid)
• Fats -- found chiefly in animals
• Oils and waxes -- found chiefly in plants
• Oils are liquid at room temperature, waxes are
solids
• Lipids along with proteins are key components of
cell membranes
• Steroids are special lipids used to build many
reproductive hormones and cholesterol
PROTEINS
• contain the elements carbon, hydrogen, oxygen,
and nitrogen
• composed of MANY amino acid subunits
• It is the arrangement of the amino acid that
forms the primary structure of proteins.
• The basic amino acid form has a carboxyl
group on one end, a methyl group that only
has one hydrogen in the middle, and a amino
group on the other end.
• Attached to the methyl group is a R group.
Major Protein Functions
•
•
•
Growth and repair
Energy
Buffer -- helps keep body pH constant