The Chemistry of Life Chapter 2 Dr. Donna Howell Biology Blacksburg High School

The Atom Everything in the universe is made of atoms. Three subatomic particles make up atoms: –Protons (+) –Neutrons (o) –Electrons (-) Example: gold (Au), silver (Ag), neon (Ne), etc.

Elements Atoms, or elements, can combine to form chemical compounds. Example: water is made of two types of atoms: hydrogen (H) and oxygen (O). The chemical formula for water is H 2 O.

Chemical Reactions There are many chemical reactions that occur in the body. These chemical reactions involve changes in the chemical bonds that join atoms in compounds. Ex: –CO 2 + H  H 2 CO 3 – (carbon dioxide combines with water to form carbonic acid, which is then carried to the lungs.)

Chemical Reactions These chemical reactions can either release energy from the bonds, which happens spontaneously, or they require energy to proceed. The energy required by some chemical reactions is called the activation energy.

Chemical Reactions Many chemical reactions in our bodies happen too slow to be of use to our bodies. Some enzymes, or catalysts, in our bodies, speed up these reactions by lowering the activation energy.

Enzyme/Substrate Complex Each enzyme is specific for a substrate (what the enzyme acts on). Example: sucrase is an enzyme that works only on sucrose, a sugar. Fits like a lock and key model.

Enzyme/Substrate Complex Enzymes are affected by: –Temperature –pH

What is an organic compound? An organic compound is a compound that contains the element carbon. –90% of all compounds in the world are organic –Our bodies are made of organic compounds

Biological Compounds There are 4 major classes of organic compounds that are called “biological compounds” because they are found in all living things: Proteins Nucleic acids Carbohydrates Lipids Monomer Polymer

Proteins Definition: large organic polymers formed from monomers of amino acids. Examples: used in the body to make up muscles, tendons, enzymes, hair, fingernails. Made of: carbon, hydrogen, oxygen, nitrogen Function: form structure of our bodies

Nucleic Acids Definition: organic polymers made of monomers called nucleotides Examples: DNA and RNA Made of: one nucleotide consists of a sugar, a phosphate group, and a nitrogen base Function: this is the hereditary information in each of our cells

Carbohydrates Definition: the simple and complex sugars in our bodies Examples: glucose, starches Made of: carbon:hydrogen: oxygen in a 1:2:1 ratio Function: serve as our body’s main short term energy source

Lipids Definition: commonly called fats Examples: fat, butter, oils, cholesterol Made of: carbon, hydrogen, oxygen in different proportions Function: serve as our body’s main energy storage molecule

Lipids There are 3 main classes of lipids: 1.Fats – lipids made by animals. Usually are solid at room temperature, and are mostly saturated. 2.Oils – lipids made by plants. Usually liquid at room temperature, and are mostly unsaturated. 3.Cholesterol – lipid produced by animals for use in cell production.

The End!