Biology · 2006 · May · Paper 2 · SL · TZ1 · Question paper

2206-6011 8 pages M06/4/BIOLO/SP2/ENG/TZ1/XX Thursday 4 May 2006 (afternoon) biology standard level PaPer 2  IB DIPLOMA PROGRAMME PROGRAMME DU DIPLÔME DU BI PROGRAMA DEL DIPLOMA DEL BI INSTRUCTIONS TO CANDIDATES • Write your session number in the boxes above. • Do not open this examination paper until instructed to do so. • Section A: answer all of Section A in the spaces provided. • Section B: answer one question from Section B. Write your answers on answer sheets. Write your session number on each answer sheet, and attach them to this examination paper and your cover sheet using the tag provided. • At the end of the examination, indicate the numbers of the questions answered in the candidate box on your cover sheet and indicate the number of sheets used in the appropriate box on your cover sheet. 1 hour 15 minutes [Personal identifier removed] 0107 22066011 2206-6011 – 2 – M06/4/BIOLO/SP2/ENG/TZ1/XX section a Answer all the questions in the spaces provided. 1. Weeds growing with crop plants can reduce yields because they compete for nutrients, water and sunlight. Synthetic chemical herbicides are often used to control these weeds. Herbicides are classified by the kinds of plants they kill and their mechanism of action. Broad-spectrum herbicides kill many different kinds of plants, but often kill the crop plant as well. Genetic engineering can create resistance to specific broad-spectrum herbicides which may solve the problem in crop plants. Different genes from bacterial sources known to protect against the effects of individual herbicides were engineered into corn plants (Zea mais). The resistance of normal and genetically engineered corn plants was