Lab 3 in a series of labs given as part of a "bioinformatics for biologists" course targeted at 2nd/3rd year undergraduates and focusing on informed use of tools. Some instructions are specific to our local computer lab setup but overall the content should be adaptable. Note that because some of the exercises make use of public databases they need to be checked and in some cases updated every time the lab is run. The lab is meant to be easily assessed using an online quiz (I use moodle). I provides a hands on introduction to NCBI BLAST, Interproscan, Clustal, MUSCLE and T-COFFEE, and HMMER.