The "Download Now" link directs you to the iTunes App Store, where you must continue the download process. You must have iTunes installed in order to open the link, and you must have an active iTunes account to download the application. This download may not be available in some countries.
From JPG Malthouse:
AminoAcidQA is an App containing about eighty revision questions and answers on amino acid metabolism. It is hoped that it will help University students revise amino acid metabolism at home or on the go. It is not an exhaustive treatment of amino acid metabolism. However, it is hoped that it will enable you to test your knowledge of key facts in amino acid metabolism.Topics include:-Amino acidsEnzymes involved in protein digestionEnzymes involved in amino acid formation and degradationExamples of medical conditions resulting from deficiencies of enzymes involved in amino acid metabolismEssential and non-essential amino acidsThe urea cycleGlucogenic and ketogenic amino acidsAmino acids used to make biomolecules other than proteins