Marek studied molecular biology and genetics at the Faculty of Science, Masaryk University in Brno, and theology in Olomouc and Brussels. He participated in two Antarctic expeditions (1997, 2000). He works at the Third Faculty of Medicine, Charles University, where he led the Institute of Ethics and Humanities (2007–2024) and was elected chair of the Academic Senate four times. For his contributions, he received the Pangea Foundation Award (2022) and the Brno City Award (2023). He is the chair of the Ethics Committee at Charles University, vice-chair of the Ethics Committee at the Ministry of Health, and an advisor to the Minister of Health. A jury member for the František Kriegel Award, he focuses on medical and environmental ethics and has authored numerous books.