As with other radiopharmaceuticals, before applied in humans, including in clinical trials, 99m Tc - GSH needs to go through a series of preclinical trials in animal first. The most dominant misconceptions profile obtained from this study are: A concept of the difference between DNA and RNA, transcription and translation stage concept and the concept ofgenetic code.Abstract: 99m Tc - glutathione ( 99m Tc-GSH) is a radiopharmaceutical which is potentially use d as a cancer diagnostic kit. The percentage students of high ability level misconception is 9,83%, the percentage students are medium skill level misconception is 16,37%, the percentage of students of lower ability level misconception 19,34%. Data collection techniques testusing method of CRI technique (Certainty of Response Index) to identify student misconceptions and using interview methods to identify profile of the student misconceptions. An instrument used in this form of tests was student's ability by using CRI (Certainty of Response Index) methodand interview. This research used 40 subjects of XII Science class with 14 students of high ability level, 11 students are medium skill level, 15 students of lower ability levels. This research is purpose to identify student misconceptions in protein synthesis material. This type of research is qualitative descriptive study. The aim of research is analyzed the misconceptions profile high school student in the country 1 Tanjungbumi class XII in protein synthesis subject material based. Transcription and translation are two important stages in the process of protein synthesis. However, in reality there are many students who are difficult to understand the biology and cause misconceptions, one of them is a protein synthesis concept because it consists stages of complex and abstract. Understanding the concept of Biology is one of the important purposes in learning objectives of Biology, a concept is not just memorized but it must be understood. Kata kunci: Pemahaman konsep Biologi, Miskonsepsi, CRI (Certainty of Response Indeks) Profil miskonsepsi paling dominan yang didapat dari penelitian ini yaitu: konsep perbedaan antara DNA dan RNA, konsep tahap transkripsi dan translasi serta konsep kode genetik. Presentase miskonsepsi siswa berkemampuan tinggi sebesar 9,83%, presentase siswa berkemampuan sedang sebesar 16,37% dan presentase siswa berkemampuan rendah sebesar 19,34%. Teknik pengumpulan data menggunakan metode tes dengan teknik CRI (Certainty of Respon Index) dan menggunakan metode metode wawancara untuk mengetahui profil miskonsepsi siswa.
Instrumen yang digunakan berupa tes kemampuan siswa dengan menggunakan metode CRI (Certainty of Respon Index) beserta wawancara. Penelitian ini menggunakan 40 subjek kelas XII IPA dengan 14 siswa tingkat kemampuan tinggi, 11 siswa tingkat kemampuan sedang, 15 siswa tingkat kemampuan rendah. Jenis penelitian yang digunakan adalah penelitian deskriptif kuantitatif. Tujuan penelitian ini adalah menganalisis profil miskonsepsi siswa di SMA Negeri 1 Tanjungbumi kelas XII pada materi pokok sintesis protein. Transkripsi dan translasi merupakan dua tahap penting dalam proses sintesis protein. Namun, pada kenyataannya masih banyak siswa yang sulit memahami pelajaran Biologi sehingga menyebabkan miskonsepsi, salah satunya adalah konsep sintesis protein karena terdiri dari tahapan-tahapan yang rumit dan abstrak.
Pemahaman konsep Biologi merupakan salah satu tujuan penting dalam tujuan pembelajaran Biologi, yaitu konsep tidak hanya sekedar dihafalkan melainkan harus dipahami.