Chemical ReactionsProcess that changes set of chemicals into another set of chemicals

Reactants yields Products 6CO2 + 6H20 C6H12O6 + 6O2

Slow Fast

Metabolism:Chemical processes occurring within a living cell necessary to maintenance life

Catabolism - Breaking Down moleculesAnabolism – Building Molecules

Reaction Energy• Energy is Released when chemical bonds Break

• Energy is Absorbed when chemical bonds Form

• Reactions that release energy Spontaneous

• Reactions that require energy Non Spontaneous

Energy requirements in chemical reactions

Energy-Releasing Reaction

Products

Activation energy

Reactants

C6H12O6 → CO2 + H2O

Burning a Log

Enzymes• Chemical reactions in the human body require a lot of

energy • Enzymes serve as a CATALYST

• Speed up reactions that take place in cells

Reaction using Enzyme

Candy Bar

Reaction pathwaywithout enzyme

Activation energywithout enzyme

Activationenergywith enzymeReaction pathway

with enzyme

Reactants

Products

Chapter 02D.mpg

CARBOHYDRATES

Characteristics of Carbohydrates

• Consist of carbon, hydrogen, & oxygen• Energy containing molecules• Some provide structure: Celulose

• Basic building block is a monosaccharide (CH2O)n ; n = 3,5,6

• Two monosaccharides form a disaccharide

Three Monosaccharides

C6H12O6

Dehydration Synthesisof a Disaccharide

Formation of Disaccharides

Hydrolysis of a Disaccharide

Important Polysaccharides: Starch

• Consists of glucose subunits

• Plant energy storage molecule

• Glycogen is a very similar molecule in animals.

• Starch and glycogen can be digested by animals.

Important Polysaccharides: Cellulose

• Composed of glucose subunits

• Different bond formed than starch

• Structural component in plants

• Cannot be digested by animals

LIPIDS

Characteristics of Lipids

• Composed of: Carbon, Hydrogen, and Oxygen

• Includes: Fats, Oils, Phospholipids, and

Cholesterol• Phospholipids part of cell membrane• Building blocks:

• Fatty Acids and Glycerol.

• Energy storage molecules

Fatty Acid Structure

•Carboxyl group (COOH) forms the acid.•“R” group is a hydrocarbon chain.

A Representative Fatty Acid

SaturatedFatty Acid

UnsaturatedFatty Acid

Glycerol

Synthesis of a Fat

A Phospholipid

PROTEINS

Characteristics of Proteins

• Contain: • Carbon, Hydrogen, Oxygen, Nitrogen, sulfur

• Function:• Structural components of animals• Control molecules (enzymes)• Transport and messenger molecules

• Basic building block is the amino acid

Amino Acid

• Amine group acts like a base, tends to be positive.• Carboxyl group acts like an acid, tends to be negative.• “R” group is variable, from 1 atom to 20.• Two amino acids join together to form a dipeptide. • Adjacent carboxyl and amino groups bond together.

Some Amino Acids

Some More Amino Acids

Still More Amino Acids

Formation of a Dipeptide

Dehydration synthesis

Amino Acid + Amino Acid --> Dipeptide

Amino Acid + Dipeptide --> Tripeptide

A.A. + A.A. + …..+ Tripeptide --> Polypeptide

A protein consists of one or morepolypeptide chains.