Biology · 2000 · May · Paper 3 · SL · Question paper

BIOLOGY STANDARD LEVEL PAPER 3 Friday 12 May 2000 (morning) 1 hour 15 minutes M00/410/S(3) INTERNATIONAL BACCALAUREATE BACCALAURÉAT INTERNATIONAL BACHILLERATO INTERNACIONAL 220-191 15 pages INSTRUCTIONS TO CANDIDATES ! Write your candidate name and number in the boxes above. ! Do not open this examination paper until instructed to do so. ! Answer all of the questions from three of the Options in the spaces provided. You may continue your answers in a continuation answer booklet, and indicate the number of booklets used in the box below. Write your name and candidate number on the front cover of the continuation answer booklets, and attach them to this question paper using the tag provided. ! At the end of the examination, indicate the letters of the Options answered in the boxes below. Number Name TOTAL /45 TOTAL /45 TOTAL /45 NUMBER OF CONTINUATION BOOKLETS USED ......... /15/15/15 /15/15/15 /15/15/15 IBCATEAM LEADEREXAMINEROPTIONS ANSWERED 10Option A — Diet and Human Nutrition Al. Proteins contain the element nitrogen. When a person is in nitrogen balance they are taking in as much nitrogen in protein as they are losing in nitrogen compounds in urine, sweat and faeces. Adult volunteers in an experiment were given a protein-free diet for one week. During this period they started to break down body tissues to obtain a supply of amino acids. Some of these amino acids were deaminated and the nitrogen excreted as urea. Each volunteer was then given a diet containing pure protein from one food source. The nitrogen intake and loss from the body was monitored. The graph below shows the net change in nitrogen content of the body at different levels of protein intake for each food source. The scales are the same for both axes and are in arbitrary units. (Source: Taylor, T G (1978), Principles of Human Nutrition, Ed Arnold) [1](a) State how many units of groundnut are required to achieve nitrogen balance. ......................................................................... [1](b) (i) Identify the protein source that can be used: most efficiently ....................................................... least efficiently