Molecules and Cells: The Building Blocks of Life

From an evolutionary point of view, RNA was most likely the first "molecule of life". Accumulating evidence suggests that life originated on earth in the so-called "RNA world". In these first living systems RNA played a central role not only for storing genetic information but also for conducting enzymatic processes. Even after DNA and protein-based functions evolved, RNA-mediated activities remained pivotal for cellular life. The importance of RNA in modern biology, is also mirrored by the fact that errors in RNA metabolism are causally linked to various diseases.

Trypanosomes are single-celled organisms and the causative agent of sleeping sickness in humans and Nagana in cattle. The organism is extremely small: Roughly 50 trypanosomes need to be aligned to obtain 1 mm in length. With the development of microscopes starting over 300 years ago, the field of biology was revolutionized, and small parasitic organisms could be observed for the first time. With the help of microscopes, Trypanosomes were discovered here in Bern in 1841. During the last centuries, the resolution and magnification of microscopes improved steadily but they also became expensive.

Postal services deliver mail, mostly to the right final destinations. This is because correctly labelled mail carries a specific address which is read and scanned by post-officers who ensure delivery. Proteins within cells, especially those destined to be sent outside of a cell’s boundaries, are just like mail in our postal service metaphor and have to be delivered to the right places within and without the cell, to function properly. Follow me on a deep-dive into how some of the simplest cells we know achieve correct protein delivery with a minimally staffed molecular post-office!