The purpose of this study is to examine, based on the biology domain of the TIMSS 2007, how well the framework`s key ideas were implemented on Korean and Singaporean science textbooks for middle school and to see the differences on how the ideas were presented and on its weight of focus between the two countries. Additionally, open questions on which Korean students scored significantly higher or lower than their Singaporean counterparts were explored to understand how each of the questions were covered on both Korean and Singaporean textbooks. In conclusion, there was no distinctive difference in presenting ``The structures and functions of an organism`` between Korean textbooks and those of Singapore. However, ``The classification of organisms`` and ``Ecosystem`` were only roughly covered or not included at all on Korean middle school science textbooks. In terms of presentation, Korean textbooks laid an excessive focus on inquiry, failing to cover concrete description of a concept. It was also shown that Korean students solved easily the items experienced frequently in their daily life and lacked practice for identifying the intention of constructed response items and providing accurate description and reasoning.