Biomolecules Carbohydrates Proteins, Lipids, and Nucleic acids

Carbon is the central element All biomolecules contain a Carbon chain or ring Carbon has 4 outer shell electrons (valence = 4) Therefore it’s bonding capacity is great It forms covalent bonds –hence, has strong bonds Once bound to other elements (or to other Carbons), it is very stable

Carbon linkages Single chains Rings Propane

Carbon binds to more than just hydrogen To OH groups in sugars To NH 2 groups in amino acids To H 2 PO 4 groups in nucleotides of DNA, ATP Amino acid These are called ‘functional groups’!

Carbohydrates (or sugars) Simple sugars (monosaccharides) Only one 6-C chain or ring involved General formula (CH 2 O)

Carbohydrates (sugars) Double sugars (disaccharides) Two 6-C chains or rings bonded together Lactose

Carbohydrates (sugars) Complex carbo’s (polysaccharides) –Starch – energy storage –Cellulose – structural support –Glycogen – energy storage –Chitin – structural Glycogen to glucose in animals Up to 10,000 glucose units!!

Proteins Composed of chains of amino acids 20 amino acids exist Amino acids contain –Central Carbon –Amine group –Carboxyl group –R group

There are four levels of protein structure Primary = sequence of aa’s Secondary = forms pleated sheet, helix, or coil Tertiary = entire length of aa’s folded into a shape Quaternary = several aa sequences linked together 1º1º 2º2º 3°3° 4°4°

Shape is critical to protein function Types of proteins Enzymes Hormones Structural proteins Receptor proteins

Nucleic acids: DNA and RNA DNA = deoxyribonucleic acid DNA is a double polymer (chain) Each chain is made of nucleotides The 2 chains bond together to form a helix

DNA nucleotides – double stranded polymer Each nucleotide in DNA contains: –5-C sugar (deoxyribose) –Phosphate –Nitrogen base -adenine (A) -guanine (G) -cytosine (C) -thymine (T)

RNA Nucleotides – single- stranded polymer Each nucleotide in RNA contains: –5-Carbon sugar – Ribose*** –Phosphate –Nitrogen base Adenine (A) Guanine (G) Cytosine © Uracil (U)***

Lipids Made of the same elements as carbohydrates, but insoluble in water Do not form polymers! Major function: –Energy storage –Insulation –Cell membranes

Types of lipids 1- glycerides Make up 90% of lipid in food Differ with respect to ‘saturated’ or ‘unsaturated’ fatty acid chains

Types of lipids 2- steroids Contain a central core of 4 rings Difference in functional groups relates to steroid function in the body 3 main forms of steroids –Cholesterol –Estrogen –testosterone

Lipids and Health Hierarchy of dietary fats: –Fats containing Omega-3 fatty acids –Mono- and poly unsaturated fats –Saturated fats –Trans fats

Lipids: 3) Phospholipids Make up cell membranes Produces a bi-layer Polar “head” region point to outside and inside of cell Non-polar “tails” only to inside of membrane