Biochemistry

Chapters 4 & 5

A. The Importance of Carbon

• 1. Organic chemistry is the study of carbon compounds 2. Carbon atoms are the most versatile building blocks of molecules 3. Variation in carbon skeletons contributes to the diversity of organic molecules

Carbon atoms have unique bonding properties.

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

• Carbon-based molecules have three general types of structures. – straight chain

– branched chain– ring

B. Functional Groups

• 1. Functional groups also contribute to the molecular diversity of life

• a. hydroxyl group and alcohols b. carbonyl group and aldehydes and ketones c. carboxyl group and carboxylic acids d. amion groups and amines e. sulfhydryl group and thiols f. phosphate groups

C. Polymer Principles

• 1. Most macromolecules are polymers 2. A limitless variety of polymers can be built from a small set of monomers

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

– Monomers are the individual subunits.– Polymers are made of many monomers.

D. Carbohydrates: Fuel and Building Material

• 1. Sugars

• a. smallest carbohydrates b. serve as fuel and carbon sources

• 2. Polysaccharides

• a. polymers made of sugars b. storage and structure

Four main types of carbon-based molecules are found in living

things.• Carbohydrates are made of carbon, hydrogen, and

oxygen.

Four main types of carbon-based molecules are found in living

things.• Carbohydrates are made of carbon, hydrogen, and

oxygen.

– Carbohydrates include sugars and starches.

– Monosaccharides are simple sugars.

– Polysaccharides include starches, cellulose (fiberous plants), and glycogen (in muscles)

• Carbohydrates can be broken down to provide energy for cells.

• Some carbohydrates are part of cell structure.

Polymer (starch)

Starch is a polymer of glucose monomers that often has a branched structure.

Polymer (cellulose)

Cellulose is a polymer of glucose monomers that has a straight, rigid structure

monomer

E. Lipids: Diverse Hydrophobic Molecules

• 1. Fats store large amounts of energy 2. Phospholipids are major components of cell membranes 3. Steroids include cholesterol and certain hormones

– Many contain carbon chains called fatty acids.– Fats and oils contain fatty acids bonded to glycerol.

• Lipids are nonpolar molecules that include fats, oils, and cholesterol.

Triglyceride

• Lipids have several different functions.

– broken down as a source of energy – make up cell membranes– used to make hormones

• Fats and oils have different types of fatty acids.

– saturated fatty acids– unsaturated fatty acids

• Phospholipids make up all cell membranes.

– Polar phosphate “head”– Nonpolar fatty acid “tails”

Phospholipid

F. Proteins: The Molecular Tools of the Cell

• 1. A polypeptide is a polymer of amino acids connected in a specific sequence 2. A protein's function depends on its specific conformation

• Proteins are polymers of amino acid monomers.

– Twenty different amino acids are used to build proteins in organisms.

– Amino acids differ in side groups, or R groups.

• Proteins are polymers of amino acid monomers.

– Twenty different amino acids are used to build proteins in organisms.

– Amino acids are linked by peptide bonds.

• Proteins are polymers of amino acid monomers.

– Amino acids differ in side groups, or R groups.

– Twenty different amino acids are used to build proteins in organisms.

• Proteins differ in the number and order of amino acids.

– Amino acids interact to give a protein its shape.

– Incorrect amino acids change a protein’s structure and function.

hydrogen bond

Hemoglobin

G. Nucleic Acids: Informational Polymers

• 1. Nucleic acids store and transmit hereditary information 2. A nucleic acid strand is a polymer of nucleotides 3. Inheritance is based on replication of the DNA double helix 4. DNA and proteins can serve as tape measures of evolution

• Nucleic acids are polymers of monomers called nucleotides.

– Nucleotides are made of a sugar, phosphate group, and a nitrogen base.

A phosphate group nitrogen-containing molecule,called a base

deoxyribose (sugar)

• Nucleic acids are polymers of monomers called nucleotides.

– DNA stores genetic information.

• Nucleic acids are polymers of monomers called nucleotides.

– Nucleotides are made of a sugar, phosphate group, and a nitrogen base.

– RNA builds proteins.

DNA

RNA