Carbon Biochemistry: The macro-molecules of Life

4 major groups of organic macromolecules are found in living things Carbohydrates (C-H-O 1:2:1 ratio) Lipids (C-H-O) Proteins (C-H-O-N)…sometimes S Nucleic Acids (C-H-O-N-P)

What is an organic molecule? Most carbon containing compounds are classified as organic, with the exception of: Simple oxides of carbon: Carbonates Most organic compounds contain C-H bonds (but Urea doesn’t)

Where is carbon on the periodic table?

Carbon has 4 valence electrons Therefore it can have bond with up to 4 other atoms

All organic molecules have two parts: The carbon backbone & the functional group Carbon has 4 valence electrons Carbon atoms can form single, double, or triple covalent bonds

Hydrocarbon chains form the skeleton of many macromolecules Hydrocarbon backbone Hydrocarbon chains form the skeleton of many macromolecules

What is a functional group? The components of organic molecules that are most commonly involved in chemical reactions are known as functional groups A functional group is a group of atoms within a molecule that interacts in predictable ways with other molecules

Functional Groups Each functional group behaves consistently from one organic molecule to another FUNCTIONAL GROUPS give organic molecules their physical properties,their chemical reactivity,  &  solubility in aqueous solutions

The Macromolecules of life

Macromolecules (but NOT lipids) are POLYMERS Polymers consist of long chains of repeating units that are either the same or similar to each other (monomers) The individual units are called monomers Only 50 common monomers make up the thousands of macromolecules responsible for life Polymers are distinguished by the different structure of their monomers Just think how many words you can make out of the 26 letters of the alphabet….

Monomer v. Polymer H2O A monomer is a single molecular unit. A polymer is a long chain of many monomers. H2O

Making and breaking polymers Polymers are synthesised from monomers using condensation reactions; when 2 monomers are combined, one water molecule is released Polymers are broken down into individual monomers using hydrolysis; when a a polymer is broken down after the addition of water

Monomer units join together via CONDENSATION REACTIONS

Hydrolysis: Breaking apart macromolecules

Condensation and Hydrolysis Reactions Condensation reactions join two sugar molecules hCondensation and hydrolysis

The major macromolecules of life Carbohydrates Fats Proteins Elements they contain C, H, O C, H, O, N, (S) Smaller molecules they are made of Monosaccharides (simple sugars) Glycerol plus fatty acids Amino acids Solubility in water Simple sugars are soluble insiluble May be soluble OR insoluble Why organisms need them Easily available energy (17 kJ/g) Storage of energy (39 kJ/g); insulation; making cell membranes Making cells; enzymes; immune function; haemoglobin Some foods that contain them Bread, cakes, potatoes, rice Butter, oils, peanuts, fatty meat Meat, fish, eggs, pulses. Tifu, milk, cheese

Carbohydrates (polysaccharides) are formed from monosaccharide monomers Simple monosaccharides join through condensation reactions to make glycosidic bonds

Proteins (polypeptides) Amino acids form polymers (polypeptides/proteins) Peptide bonds are formed from condensation reactions

Lipids are macromolecules, not polymers… Ester bonds are formed by condensation reactions

Carbohydrates The monomer is called a monosaccharide (simple sugar) Carbohydrates are soluble in water It has the formula: a 1:2:1 ratio of C:H:O

Carbohydrates The polymer is called a polysaccharide The bond made by condensation reactions is a glycosidic bond Examples of polysaccharides include starch, cellulose, chitin

Proteins The monomer is called an amino acid Amino acid structure: NH2 – C-® - COOH Amino acids differ due to the R (functional) group The structure of the R-group determines the chemical properties of the amino acid Proteins can be soluble OR insoluble in water

Proteins The polymer is called a polypeptide The bond formed by a condensation reaction is a peptide bond Examples of polypeptides include enzymes, keratin, haemoglobin…

Lipids Lipids consist of a glycerol molecule, joined to 2 or three fatty acid molecules by a condensation reaction The bond formed is an ESTER bond They are NOT polymers They are insoluble in water Glycerol

Carbohydrates Fats Proteins Elements they contain C, H, O C, H, O, N, (S) Smaller molecules they are made of Monosaccharides (simple sugars) Glycerol plus fatty acids Amino acids Solubility in water Simple sugars are soluble insiluble May be soluble OR insoluble Why organisms need them Easily available energy (17 kJ/g) Storage of energy (39 kJ/g); insulation; making cell membranes Making cells; enzymes; immune function; haemoglobin Some foods that contain them Bread, cakes, potatoes, rice Butter, oils, peanuts, fatty meat Meat, fish, eggs, pulses. Tifu, milk, cheese