Chapter 5 Macromolecules

Building blocks of life

Macromolecule Composition

• Monomers• Polymer• Covalent linkages• Dehydration reactions• Hydrolysis reactions

Categories of Macromolecules

• Carbohydrates• Lipids• Proteins• Nucleic acids

Carbohydrates

• Sugars• Sugar polymers• Glycosidic linkage

– Covalent

• Categories– Monosaccharide– Disaccharide– Polysaccharide

Monosaccharides

• Single sugar molecule• Can function as

monomer• Ring form• Aldoses• Ketoses

Ring Forms of Sugars

Disaccharides

• Two sugar molecules• Dehydration reaction• Glycosidic bond• Sucrose• Lactose• Maltose

Derivatives of Carbohydrates Sweeteners

Polysaccharides

• Many sugar molecules

• Glycosidic linkage• Starch

– Alpha

• Cellulose– Beta– Structural

polysaccharide

• Chitin

Lipids

• Fats and oils• Hydrocarbon tails or

rings• Very non polar• No true monomer• Most composed of

glycerol and fatty acids

• Linkage-ester

Subcategories of Lipids

• Neutral lipids

• Phospholipids

• Steroids

• Waxes

Neutral Lipids

• Glycerol backbone• 1, 2, or 3 fatty acids• Triglyceride• Ester linkage• Adipose storage• Plant oils• Saturated- animal source• Unsaturated- plant source

Phospholipids

• Glycerol backbone• 2 fatty acid tails• Phosphate head• Amphipathic• Polar head• Non-polar tails• Components of all

biological membranes

Phospholipids (cont.)

• Bilayer• Micelle• Liposome• Emulsifying agent

Steroids

• Common ring structure

• Very planar• Sex hormones• Cholesterol

– Stabilize membranes

Waxes

• Very hydrophobic• Long chain alcohol

esterified to very long chain fatty acid

• Waterproofing• Ducks

Proteins

• Polymers of amino acids

• Amino acid as monomer

• Peptide bonds• Very diverse group of

macromolecules

Amino Acids

Amino Acids

Essential Amino Acids

• Animal sources

• Plant sources– Complementation groups

Protein functions

• Enzymatic proteins• Structural proteins• Storage proteins• Transport proteins• Hormonal proteins• Receptor proteins• Contractile and motor proteins• Defensive proteins

Enzymatic Proteins

• Catalyst• Rate of reactions• Energy changes• “Match maker”• Shape• Active site• Activation energy

Structural Proteins

• Confer shape • Capsid proteins• Cytoskeletal proteins

Storage Proteins

• Albumin• Amino acid storage• Egg white

Transport Proteins

Receptor protein

• Hormones• Viruses• Cell communication

Contractile Proteins

Defense Proteins

• Antibodies

Protein Structure

• Four levels of organization

• Primary

• Secondary

• Tertiary

• Quaternary

• See pages 82-83 in text

Primary and Secondary

Tertiary and Quaternary

Denaturation

• Unfolding• Break H bonds• Heat• pH changes

Protein Folding

• Hydrophilic interactions

• H bonding • S-S bridges• Chaparonins

Amino Acid Sequence

• Ultimately determined by the DNA base sequence

• Dictates final folding and shape

Nucleic Acids

• Polymers of nucleotides

• DNA• RNA

Nucleotides

• 5 carbon sugar– Ribose– Deoxyribose

• Nitrogenous base– Adenine– Guanine– Cytosine– Thymine– Uracil

• Phosphate- 1, 2, or 3

Nitrogenous base

• Letters in genetic code

• Purines– Adenine– Guanine

• Pyrimidines– Thymine– Cytosine– Uracil

Structure of Nucleic acids

• Sugar/ Phosphate back bone- similar to paper

• N base as “letter” written on the backbone

• Anti-parallel alignment if double stranded

Functions of Nucleic Acids

• Information molecules• DNA

– Hereditary information– Recipe book– Each recipe is one

gene– Each gene encodes

one protein

• RNA– Working copy of one

gene or recipe

DNA

• Hereditary function– DNA replication

• Master recipe book– Transcription

RNA

• Working copy of a gene

• Transcription– Make RNA

• Translation– Make protein