The pharmaceuticals and biotechnology sector was among the best performing sectors on Monday, helped by its giant constituent GlaxoSmithKline.The FTSE 100 drugs and healthcare firm announced that it is to buy up over a quarter of UK-based biotech firm Autifony Therapeutics through its wholly-owned subsidiary, Glaxo Group. Glaxo is to invest £1.25m in Autifony is exchange for a 25.4% minority equity stake. Shares rose 3.18% to 1,282p at 15.32.Sector peer AstraZeneca was also making gains of over 4%.Meanwhile, the banks were on their way lower, led by the part-nationalised lender, Royal Bank of Scotland, whose shares were falling 3.7% to 20p in the afternoon.Sector peers Barclays, Standard Chartered and Lloyds were also out of favour on the blue chip index.BCTop performing sectors so far todayIndustrial Metals & Mining 5,270.48 +4.51%Pharmaceuticals & Biotechnology 9,020.47 +3.09%Mobile Telecommunications 3,721.06 +2.64%Construction & Materials 2,974.76 +2.39%Oil Equipment, Services & Distribution 20,543.50 +2.35%Bottom performing sectors so far todayAutomobiles & Parts 4,192.15 -2.29%Banks 3,299.91 -1.32%Personal Goods 19,530.58 -0.79%Real Estate Investment & Services 1,452.25 -0.25%