Nominations for coveted prize set to begin this week

This year's Nobel Prize in Physiology or Medicine has been won by Swedish scientist Svante Paabo for his research in human genetics. Paabo made the ground-breaking discovery of an extinct human sub-species which sheds new light on the human immune system. There are five Nobel prizes in all, and they're regarded as the world's most prestigious awards. Let's take a look at how recipients are chosen, and what winning a Nobel prize really means