In preparation for a study of essay questions and other forms of open-ended exercises in the California Golden State Examination for biology, the functioning of open-ended biology items in another examination was explored. The Golden State Examination program offers honors credit to students who wish to qualify for admission to programs in California's community college and university system. Test materials and data from the January 1989 grade 12 Alberta (Canada) Diploma Examination in biology were used. A quantitative analysis was made of the relative information about the student's proficiency in biology that is conveyed by the multiple-choice and open-ended items in the Alberta test. An item factor analysis carried out on the full sample of 8,113 examinees revealed the test to be highly unidimensional. A random sample of 2,000 cases was subjected to item response theoretic information analysis. Results suggest that the multiple-choice section has very high reliability and further suggest that one of the open-ended items conveys, on the average, about the same information as four multiple-choice items. The relatively greater efficiency of the multiple-choice items does not, however, imply that they should be used exclusively in measuring science achievement. The implications of the Alberta test for the construction of open-ended questions for the Golden State examination are discussed. Four figures and two tables present results from the test analyses. An appendix contains nine examples of open-ended problems with scoring information. (Contains four references.) (SLD)