Macromolecules

Building Blocksof Life

Macromolecules• Smaller organic molecules join together to

form larger molecules– macromolecules

• 4 major classes of macromolecules:– carbohydrates– lipids– proteins– nucleic acids

Monomer + Monomer = Polymer

• Carbs, Proteins, Nucleic Acids are made of chain-like repeating units

• Chains of single units (monomers) make polymers

Polymers• Long molecules built by linking repeating

building blocks in a chain – monomers • building blocks• repeated small units

– covalent bonds• Why is Carbon so good at this??

H2O

HO

HO H

H HHO

How to build a polymer• Dehydration Synthesis:• joins monomers by “taking” H2O out

• one monomer donates OH–

• other monomer donates H+ • together these form H2O

– requires energy & enzymes

enzymeDehydration synthesisDehydration synthesis

H2O

HO H

HO H HO H

How to break down a polymer• Hydrolysis:• use H2O to breakdown polymers

• reverse of dehydration synthesis• cleave off one monomer at a time

• H2O is split into H+ and OH–

– H+ & OH– attach to ends

– requires enzymes– releases energy

HydrolysisHydrolysis

enzyme

1. Carbohydrates (C,H)• Are sugars and polymers of sugars– Monosaccharides: one sugar– Disaccharides: two sugars– Poly saccharides: more than two sugars

• Store short term energy

Monosaccharides

• Simple sugars that provide short term energy

• Ex: glucose

Disaccharides• Monosaccharide + Monosaccharide• Formed via dehydration synthesis• Ex: sucose

Disaccharide

Polysaccharides

• Complex starches that store short term energy• Glycogen: hydrolyzed in the liver when sugar supplies

are low

Structural Polysaccharides

• Cellulose: cell walls

• Chitin: exoskeletons

2. Lipids (C, H, O, sometimes P)

• The smallest of the macromolecules• Not a true polymer (different monomers)– Glycerol head– Fatty acid tail

• Storage of long-term energy

Fats

Steroids

Phospholipids

• Cell membranes phosphorus

3. Proteins (C, H, O, N, sometimes S)

• 3 Dimensional polymers– Monomers: amino acids– Polymer of amino acids

is called a polypeptide– Held together by

covalent peptide bond– Protein is one or more

polypeptides

Many Functions

• Speed up reactions

• Structure• Storage• Transport• Communication• Movement• Defense

Amino Acids

• 20 amino acids build thousands of proteins

• Each one has an amino group, carboxyl group, H, and R-group

4 Levels of Protein Structure• Primary: amino acid

chain held by peptide bonds

• Secondary: hydrogen bonds between H & carboxyl α-helix or β-pleated sheet

4 Levels of Protein Structure, cont.

• Tertiary: R-groups interact further folding the protein

• Quaternary: aggregation of polypeptides

Just how important is primary structure?

4. Nucleic Acid (C, H, O, N, P)• Storage of heritable

information– DNA and RNA

• Monomers: nucleotides– Sugar (ribose or

deoxyribose)– Phosphate group– Nitrogen base (A, G,

C, T, U)

DNA: deoxyribonucleic acid

• Genetic material inherited from parents to offspring

• Self-replicating• Does not code

directly for protein (needs RNA assistance)

RNA: ribonucleic acid

• Used by the cell to decode DNA’s instructions for protein

• DNA RNA Protein• Central Dogma of

Genetics