2.3: Carbon-

Based Molecules

Carbon-based molecules are the foundation of life.

Bonding Properties of Carbon

• Carbon forms covalent bonds with up to four other atoms, including other carbon atoms.

1

2 3, 4

Structure of carbon-based molecules…

• Three general types:

1. straight chain

H H Cl H H | | | | | H - C- C - C - C - C - H | | | | | H H H H H 3-chloropentane

Structure of carbon-based molecules…

• Three general types:

2. Branched chain

Structure of carbon-based molecules…

• Three general types:

3. Ring

• Many carbon-based molecules are made of many small subunits bonded together.

– Monomers are the individual subunits.

– Polymers are made of many monomers.

Four Types of Carbon-

Based Molecules

Carbohydrates

Lipids

Proteins

Nucleic Acids ALL four are found in LIVING things.

Carbohydrates

• Organic molecules made of the elements carbon, hydrogen, and oxygen (CHO)

• Includes sugars and starches

• Pasta, bread, and fruit are high in carbohydrates

Structure of Carbohydrates

• Monomer • Monosaccharides

– “saccharide” means sugar

– simple sugars

– Glucose, galactose, fructose

Structure of Carbohydrates

• Disaccharide

• Two monosaccharide molecules bonded together

• Sucrose, or table sugar, made of one glucose and one fructose molecule

Structure of Carbohydrates

• Polymer • Polysaccharides

– Chains of monosaccharides

– starches, cellulose, and glycogen

Function of Carbohydrates

• Can be broken down to provide energy for cells. – Glucose-main source of energy

for cells, product of photosynthesis

• Provide us with energy – Sugar rush then crash

• Some carbohydrates are part of cell structure. – Cellulose-makes up the cell wall

of plant cells

LIPIDS • Organic molecules made

of the elements carbon, hydrogen, and oxygen (CHO)

• Nonpolar molecules –Do not dissolve in water

• Include fats, oils, cholesterol, and wax

Structure of Lipids

• Fatty acids bonded to glycerol. – Glycerol-3 hydroxyl

groups – Fatty acids-long carbon

chains Two different types of

fatty acids found in fats and oils: oSaturated fatty acids oUnsaturated fatty

acids

Two Types of Fatty Acids

Functions of Lipids • Used for long term energy

storage

• Make up cell membranes – Phospholipid bilayer

• Used to make hormones – Testosterone (males) & estrogen

(females)

• Insulate and waterproof organisms – Cutin-waxy substance that

coats leaves of plants to help prevent water loss

Lipid Polymer-Phospholipid

• Consists of glycerol, two fatty acids (nonpolar tails) and a phosphate group (polar head of molecule)

• Makes up ALL cell membranes

Lipid Polymer-Triglycerides

• Consists of glycerol and three fatty acids

• Type of fat found in your blood.

– Your body uses them for energy.

• You need some triglycerides for good health.

– But high triglycerides can raise your risk of heart disease and may be a sign of metabolic syndrome

Nucleic Acids

• EXTREMELY long carbon-based molecules made of carbon, hydrogen, oxygen, nitrogen, and phosphorus (CHONP)

Structure of Nucleic Acids

• Monomer – Nucleotide

• made of a five-carbon sugar, phosphate group, and a nitrogen base.

• 5 kinds: Adenine, Thymine, Cytosine, Guanine, & Uracil

• Polymers – DNA-Deoxyribonuleic

Acid

– RNA-Ribonucleic Acid

A phosphate group

nitrogen-containing molecule, called a base

deoxyribose (sugar)

Function of Nucleic Acids

DNA

RNA

• DNA stores genetic information

• RNA builds proteins using information from DNA