Biology · 2010 · November · Paper 3 · HL · Question paper

8810-6003 19 pages N10/4/BIOLO/HP3/ENG/TZ0/XX Wednesday 3 November 2010 (morning) BIOLOGY HIGHER LEVEL PAPER 3 INSTRUCTIONS TO CANDIDATES • Write your session number in the boxes above. • Do not open this examination paper until instructed to do so. • Answer all of the questions from two of the Options in the spaces provided. You may continue 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 letters of the Options answered in the candidate box on your cover sheet and indicate the number of answer sheets used in the appropriate box on your cover sheet. 1 hour 15 minutes [Personal identifier removed] © International Baccalaureate Organization 2010 0 1 1 9 8 8 1 0 6 0 0 3 8810-6003 – 2 – N10/4/BIOLO/HP3/ENG/TZ0/XX Option D — Evolution D1. Superoxide dismutase is an enzyme used by cells to protect themselves against oxidative damage. These enzymes can have different metals as part of their structure. A study to compare two dismutases from Escherichia coli bacteria and two dismutases from eukaryotic cells was undertaken. The following enzymes were used: • E. coli dismutase with iron (Fe) • E. coli dismutase with manganese (Mn) • eukaryotic mitochondrial dismutase with manganese (Mn) • eukaryotic cytoplasmic dismutase with copper-zinc (Cu-Zn). The following shows part of the amino acid sequences of these enzymes. Boxes enclose identical amino acids in the sequence of the two E. coli and mitochondrial dismutases. 1 5 10 15 E. coli (Fe) Ser – Phe – Glu – Leu – Pro – Ala – Leu – Pro – Tyr – Ala – Lys – Asp – Ala – Leu – Ala E. coli (Mn) Ser – Tyr – Thr – Leu – Pro – Ser – Leu – Pro – Tyr – Ala – Tyr – Asp – Ala – Leu – Glu Mitochondrial (Mn) Lys – His – Thr – Leu – Pro – Asp – Leu – Pro – Tyr – Asp – Tyr – Gly – Ala – Leu – Glu Cytoplasmic (Cu-Zn) AcAla – Thr – Lys – Ala – V al– Cys – V al– Leu – Lys – Gly – Asp – Gly – Pro – V al– Gln 16 20 25 E. coli (Fe) Pro – His – Ile – Ser – Ala – Glu – Thr – Ile – Glu – Tyr – His – Tyr – Gly – Lys E. coli (Mn) Pro – His – Phe – Asp – Lys – Gln – Thr – Met – Glu –