This thesis sets out to examine students conceptions about Mendelian inheritance within an independent writing task and their reference to other parameters. Starting with a short overview of the influence of independent writing on knowledge acquisition during science lessons, the thesis continues with a short explanation of the influence of motivation on the teaching method of independent writing and knowledge acquisition. There is a link between some known students conceptions about genetics and the branch of Mendelian inheritance, which were summarized. For the practical part of the thesis, 43 texts of 8th grade students about Mendelian inheritance, which were first produced within the province-crossing and interdisciplinary project NAWIskript, were evaluated with regard to linguistic and scientific aspects. In the course of this, many different concepts and misconceptions about Mendelian inheritance were identified and analyzed, a lot of which were connected to one of the six terms that were supposed to be included and explained within the writing task (dominant, recessive, genotype, phenotype, heterozygous, homozygous). Correlation values were calculated between the results of this evaluation, the results of a motivation test, the results of a knowledge test and the gender of the students. Interesting and highly significant correlations were found between the scientific and linguistic aspects of the students texts, especially regarding the overall coherence, the number of auxiliary verbs and the number of correctly carried out concepts. No correlations were found between the results of the motivation tests and the rest of the results. Because of problems with the chosen questions, only small parts of the results of the knowledge tests could be included in the calculation. No significant correlations where found in this part of the calculation.