In TEREBRA you are a scientist who fights antibiotic-resistant bacteria that cause global epidemic diseases. Your job is to develop new antibiotics made of peptides that can keep up with resistant strains of bacterial pathogens: Keep designing efficient antibiotics and save the world!
How do you create the peptide antibiotics, and how do they work?
Every bacterium has a cell wall, like the thin rubber layer of a balloon, to keep the organism together. Tiny pores in the cell wall enable the bacteria to exchange chemical substances with the outside world. These tiny openings can be torn open by the right peptide antibiotics, similar to the way a crowbar can be used to break open a locked door. With the correct shape and fitting through the gap in this door, peptide antibiotics can enter the cell and rip its wall apart - destroying the bacterium like a burst balloon. In Terebra, it is up to you, to create the right "molecular crowbars".
The peptides you are going to create consist of amino acids that have to be combined and folded. They have to be assembled like a chain, always linking a circle with an arrow. Once your combination fits the membrane's opening, you have successfully created an effective antibiotic peptide and destroyed the nasty disease causing bacteria. If the cell wall is ripped apart that means you saved the world from a pandemic disease. But nature strikes back and you will face a new challenge in the next level. The longer you play, the more resistant the bacteria become, making it increasingly difficult to dispatch them.
Your time to develop the new drug is limited, as the epidemic spreads all across the world. The counter lets you watch as the global population decreases. Time is running out, while more and more people fall victim to the infectious disease. So the sooner your peptide is completed, the more people actually survive. Between epidemic outbreaks (or levels) the world population gets the chance to recover a little, but don't become let that lull you into a false sense of security: the next epidemic is just around the corner!
If you see your scientific endeavours failing and time is running out, but you just can't find the right peptide, you can stop developing your drug and send people into quarantine by pressing the quarantine button. This will save your remaining population, but the downside is they will hardly recover between epidemics. Keep in mind, though, that you can only use this button three times!
Since billions of years, nature only provides 20 different amino acids to build all the peptides we know today. These famous 20 are called "canonical amino acids". In fact, chemistry knows many more amino acids, but they are simply not used by natural life forms. Facing ever more complex cell walls to break into, you'll be able to use these new elements once you reach higher levels. These "noncanonical amino acids" will enable you to build even more sophisticated structures, in order to keep up with how fast the bacteria evolve.
Enzymes are like molecular machines that can modify peptides after they've been assembled. At an advanced level in the game, you'll be offered a very promising enzyme that was recently discovered in bacteria living in sea sponges in coral reefs.. With this marine enzyme you can flip your aminoacid over, providing you a mirrored version of the initial molecule. Cell walls of highly resistant bacteria can only be broken up with the help of of flip-flop amino acids.
The more bacterial diseases you can fight and the more people survive each time, the higher you will score. Now it's up to you! You're on a mission to save mankind from extinction, as resistant bacterial diseases become pandemic.