Proteins & Nucleic Acids

• Proteins make up around 50% of the bodies dry mass and serve many functions in the body including: – Enzymes - Catalysts that selectively speed up chemical

reactions – Storage – Defense against foreign substances – Structural components – Transport molecules – Movement (Muscles)– Cellular communications

Proteins• Proteins are made of one or more

polypeptides made from 20 amino acids. – All amino acids contain the same

backbone with amino and carboxyl side groups and differ only in their functional groups (-R).

– The carbon in the middle is called the a carbon. Attached to it is the a hydrogen atom and -R. • The side chains determine the

individual characteristics of an amino acid

Peptide Bonds

• Bonds between amino acids are called peptide bonds and are formed via dehydration synthesis.– A union of many amino acids

forms a polypeptide

4 levels of protein structure• primary - sequence of amino

acids • secondary - b pleat or a helix • tertiary - 3D structure aided

by the formation of H-bonds, Van der Waals interactions (hydrophobic attraction), & disulfide bridges (-S-S-)

• quaternary - 2 or more polypeptides wound into one macromolecule.

Nucleic Acids

• Macromolecules containing C, H, O, N, P!• Nucleic acids transmit and store Genetic

information• 2 basic types:– DNA (Deoxyribonucleic acid)– RNA (Ribonucleic acid)

Nucleic Acid Structure

• 3 parts– 5-carbon sugar makes up the backbone– Phosphate group – Nitrogenous base (AGCT or U)