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