Biology · 2011 · May · Paper 2 · SL · TZ1 · Question paper

Examination code 2 2 1 1 – 6 0 1 1 16 pages M11/4/BIOLO/SP2/ENG/TZ1/XX Wednesday 18 May 2011 (afternoon) Biology Standard level PaPer 2 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 questions. • Section B: answer one question. • Write your answers in the boxes provided. 1 hour 15 minutes [Personal identifier removed] © International Baccalaureate Organization 2011 0116 2211601 1 – 2 – M11/4/BIOLO/SP2/ENG/TZ1/XX Section a Answer all questions. Write your answers in the boxes provided. 1. PanI is a gene in cod fish that codes for an integral membrane protein called pantophysin. Two alleles of the gene, PanIA and PanIB, code for versions of pantophysin, that differ by four amino acids in one region of the protein. Samples of cod fish were collected from 23 locations in the north Atlantic and were tested to find the proportions of PanIA and PanIB alleles in each population. The results are shown in pie charts, numbered 1–23, on the map below. The proportions of alleles in a population are called the allele frequencies. The frequency of an allele can vary from 0.0 to 1.0. The light grey sectors of the pie charts show the allele frequency of PanIA and the black sectors show the allele frequency of PanIB. 70 N 65 N 60 N 55 N 50 N 5 18 20 21 15 19 5 6 7 8 9 10 12 13 11 14 17 16 2 1 3 4 22 2323 15 W 1 0 W 5  W 0  W 5  E 10  E RAJ Case et al “Macro- and micro-geographic variation in pantophysin (PanI) allele frequencies in NE Atlantic cod Gadus morhua” MEPS 301: 267–278 (2005). Figs 1 and 3. (This question continues on the following page) 0216