Biochemistry
Compounds Compounds are
made up of atoms of two more elements in fixed proportions
Held together by chemical bonds Covalent Ionic
Covalent Bond Forms when two
atoms share one or more pairs of electrons
Example: Carbon Dioxide (CO2)
Ionic Bonds One atom loses
electrons while the other atom gains electrons
Example: Sodium Chloride (NaCl)
Oxidation Reduction Reactions Oxidation Reactions- A reactants loses
one or more electrons, becomes positive Undergoes oxidation
Reduction Reaction- reactant gains one or more electrons, becomes negative Undergoes reduction
**Always occur together!
Importance of Water
Water One of the most important
compounds in living organisms Means of transport Water makes up 70% of most
organisms The world is 70% water
Polarity Water is a polar compound
Charges are unevenly distributed Oxygen pulls slightly on the electrons
giving it a slightly negative charge Meanwhile, the hydrogen atoms are
slightly positive
Hydrogen Bonding Hydrogen bond-
force of attraction between a hydrogen molecule of a partial positive charge and another atom with a negative charge
Allows water to easily bond with itself
Form, break and reform easily with each other
Adhesion and CohesionAdhesion Attractive force
between water and a different substance
Allows water to stick to other surfaces
Capillary action- water can rise up a tube against the force of gravity
Cohesion Attractive force
between water molecules
Allows water molecules to stick to other water molecules
Surface tension- molecules of the surface pull downward Acts like a “skin”
Carbon Compounds
Carbon Compounds Organic compounds are
made primarily from carbon
Bonds readily because Has 4 valance
electrons Bonds easily with
other carbon Forms straight chains,
branched chains, or rings
Enormous variety of compounds
Carbon Compounds
Functional groups influence the characteristics of molecules
Cluster of atoms at one end Table 3.1 on page 52 highlights these
groups
Carbon Molecules Monomers- single unit of a carbon
compound Polymers- repeated, linked monomers
bonded together Macromolecules- made up of many
large polymers
Condensation and Hydrolysis Reactions
Condensation
Linking monomers to create polymers
Each time you add a monomer water is released
Hydrolysis
Breaking down of polymers to monomers
Water is used to break the bond
Molecules of Life
Carbohydrates Composed of
carbon, hydrogen and oxygen
1:2:1 ratio Source of energy Exist as
monosaccharides, disaccharides, and polysaccharides
Monosaccharides Monomer of
carbohydrate Also called a
simple sugar Most common
Glucose Fructose Galactose
Monosaccharides Glucose, fructose and galactose all
have same molecular formula C6H12O6
Have different structures These different structures give each
slightly different properties Called isomers
Disaccharides Two
monosaccharides combine
Also called a double sugar
Example: sucrose
Polysaccharides Complex molecule
composed of three or more monosaccharides
Storage of energy Animals store in the
form of glycogen (highly branched chain)
Plants store in the form of starch (branched chains and unbranched chains)
Proteins Composed mainly of carbon,
hydrogen, oxygen and nitrogen
Formed by linking of monomers called amino acids
Amino Acids 20 different amino acids Same basic structure
Single hydrogen atom
Carboxyl group (COOH)
Amino group (NH2) R group (difference)
Allows for very different shapes of proteins
Dipeptides and Polypeptides Two amino acids can form a dipeptide
through a peptide bond
Most often long chains of amino acids bond to form a polypeptide
Enzymes Act as a catalyst for reactions Most are proteins Very specific to environments
If environment changes slightly, enzyme probably won’t work
Lipids Non-polar Do not dissolve in water Higher ratio of carbon
and hydrogen atoms to oxygen atoms
Store more energy Include
Fatty acids Triglycerides Phospholipids Steroids waxes
LipidsFatty Acids Unbranched carbon
chains Long carbon chain with
a COOH attached at one end
One end is polar and one end in non-polar Hydrophillic- “water
loving” Hydrophobic- “water
fearing”
Triglycerides Composed of three
molecules of fatty acid joined to one molecule of alcohol glycerol
LipidsPhospholipids Two fatty acid
molecules attached to one molecule of glycerol
Have an attached phosphate group
Makes up the cell membrane
Waxes Long fatty acid chain
joined to a long alcohol chain
Water-proof Form protective coatingsSteroids Four fused carbon rings
with different functional groups attached
Hormones
Nucleic Acids Store and transfer
important information for the cell
Deoxyribonucleic Acid DNA Contains characteristics
of the organism and directs cell activities
Ribonucleic Acid RNA Stores and transfers
information needed to make proteins