3.13 Amino acids, proteins and DNA

Amino acids, proteins and DNA are the molecules of life.

The new syllabus from 2015 has significantly expanded the knowledge content for this topic.
New topics include: ‘action of anticancer drugs’ , ‘DNA’ , ‘enzymes’  and updated ‘proteins’  section.

Available at present, is the current 2015 A2 specification notes  (Amino Acids pdf) and powerpoint for Amino Acids


Action of anticancer drugs - This topic links with transition metals as cisplatin is an example of a square planar complex . The Pt(II) complex cisplatin is used as an anticancer drug. Cisplatin prevents DNA replication in cancer cells by a ligand replacement reaction with DNA in which a bond is formed between platinum and a nitrogen atom on guanine. Appreciate that society needs to assess the balance between the benefits and
DNA - [New topic from 2015] The structures of the phosphate ion, 2-deoxyribose (a pentose sugar) and the four bases adenine, cytosine, guanine and thymine are given in the Chemistry Data Booklet. A nucleotide is made up from a phosphate ion bonded to 2-deoxyribose which is in turn bonded to one of the four bases adenine, cytosine, guanine and thymine. A single strand of DNA (deoxyribonucleic acid)
Enzymes - [New topic from 2015] Enzymes are proteins. The action of enzymes as catalysts, including the concept of a stereospecific active site that binds to a substrate molecule. The principle of a drug acting as an enzyme inhibitor by blocking the active site. Computers can be used to help design such drugs. Students should be able to: explain why a stereospecific active site can
Proteins - [2015 Syllabus updates are colour highlighted] Proteins are sequences of amino acids joined by peptide links. Hydrolysis of the peptide link produces the constituent amino acids. Mixtures of amino acids can be separated and identified by thin-layer chromatography The importance of hydrogen bonding and sulfur–sulfur bonds in proteins. The primary, secondary (α-helix and β–pleated sheets) and tertiary structure of proteins. Amino acids can be located
Amino acids - Amino acids have both acidic and basic properties, including the formation of zwitterions. Students should be able to draw the structures of amino acids as zwitterions and the ions formed from amino acids: • in acid solution • in alkaline solution.