Macromolecules Building Blocks of 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??

H2OH2O HO H HH How to build a polymer Dehydration Synthesis: joins monomers by “taking” H 2 O out one monomer donates OH – other monomer donates H + together these form H 2 O – requires energy & enzymes enzyme Dehydration synthesis

H2OH2O HOH H H How to break down a polymer Hydrolysis: use H 2 O to breakdown polymers reverse of dehydration synthesis cleave off one monomer at a time H 2 O is split into H + and OH – – H + & OH – attach to ends – requires enzymes – releases energy Hydrolysis 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