Water molecules can react to form ions.

H2O <> H+ and O+ = Water <> hydrogen and hydroxide ion

The number of negative and positive ions produced is equal, so the water remains neutral. But, the charge of water enables it to act as a universal solvent.

pH Scale

Indicates the concentration of H+ ions in solutions. The scale ranges from 0-14. Increases by values of 10 (3 is 10x more acidic than 4). At 7, the solution is neutral. Below 7, it is acidic. Above 7, it is basic.

Acids

A compound that forms H+ ions in solution.

pH value below 7

Strong acids pH 1-3

Examples: Hydrochloric acid in stomach

Bases

A compound that produces hydroxide atoms in solution.

pH value above 7

Strong bases 11-14

Examples: Soap/lye, cleaning products

Buffers

Weak acids or bases that can react with strong acids or bases to prevent changes in pH.

Many buffers are in the human body to help maintain homeostasis.

Macromolecules

Carbohydrates

Function: energy storage, forms cell membranes, chemical messengers, protection/insulation

Monomer (subunit): Monosaccharides (glucose + fructose)

Examples: glucose (sugar), starch, glycogen, cellulose

Lipids

Function: energy storage

Monomer (subunit): Glycerol + fatty acids

Examples: Fats, Oils, Waxes, Cholesterol, Vitamins, Phospholipids (cell membrane)

Proteins

Function: storage, transport, regulatory, movement, structural, enzymes

Monomer (subunit): Amino Acids

Examples: Keratin (hair, nails), muscles, silk, nuts, beans, albumin, hemoglobin, insulin

Nucleic Acids

Function: carries genetic information to make proteins

Monomer (subunit): Nucleotides

Examples: DNA, RNA

Chemical Reactions

Enzyme: a protein catalyst that can decrease the energy border (speeds up a reaction).

Activation energy is lower with an enzyme activation.

The Lock and Key Model

The enzyme is unchanged and can repeat the process.

Enzyme activity is influenced by

• temperature

• salt concentration

• pH

• denaturing

Denaturing is the process in which an enzyme changes shape, leading it to no longer work.