Understanding Norn Biochemistry (Creatures 2)

The great thing about Creatures is that you end up learning about Biology while you're playing the game. But for those of you unfamiliar with Biology, seeing a list of different chemicals and not knowing the importance of each can be a little scary. Fear not, help is at hand!

Here's an introduction to Norn biochemistry with an explanation of what happens in each organ - we'll leave a discussion of the reproductive and immune systems for another day. In this article, we concentrate on digestion and keeping your Norns full of boundless energy.

Biochemistry of a Norn's digestion

The levels of different chemicals in a Norn are changing all the time. Simply existing uses up energy and Norns need to eat, preferably starch-rich foods such as cheese, to replenish their energy supplies. But just like us, Norns need a balanced diet of protein, starch and fat. Not too much fat, however, or they'll get heart disease.

Food digested in the Norn's stomach is broken down by enzymes - protein into amino acids, starch into glucose and fat into fatty acids. These three metabolites are extremely important:-

Amino acids are used to build muscles and other Norn body tissues. But the body has a "waste not, want not" attitude. Any surplus to requirements is converted to glucose with the production of ammonia. Ammonia is a rather toxic chemical and needs to be made into the less harmful form, urea, in the liver and then discarded from the body via the kidneys.

Glucose is the chemical that gives you an immediate pick-up. It is very rapidly converted to pyruvate in the heart and when there's oxygen around, it is broken down, releasing energy and carbon dioxide. This energy is then captured as ATP for use anywhere in the body. If there isn't much oxygen around, then the pyruvate is converted to lactate. As soon as oxygen levels rise back to normal, the lactate is converted back to pyruvate. The build up of lactate is a sign that the Norn is short of oxygen and will have little energy until normal oxygen levels are returned.

Any excess glucose is converted into a short-term energy store, glycogen, in the liver. Glycogen can be easily mobilised so when a Norn begins to get hungry, he'll start converting glycogen back to glucose. Too much glucose and insulin in the Pancreas Beta converts it to fatty acids and you'll find that the Norn's glucose high suddenly drops - not down to dangerous levels but it'll dip down before coming back up to normal again.

Fatty acids are converted in the Pancreas Beta to adipose with an intermediate step via triglycerides. Adipose is a long-term energy store and it can sit there quite happily until its ready to be converted back to fatty acids and ultimately glucose. But since adipose tends to congregate around the heart, you have to be careful not to over-stock the energy store!

All of this is explained in our biochemistry pathway graphic and you can see easily in which organs these reactions occur. Click on any organ to find out what is does and see where it is located in the body.

Please note: Although there are differences between a Norn's biochemistry and that of a typical mammal's, many of the concepts are remarkably similar. That's because in an attempt to create artificial life, CyberLife has modelled real biochemical processes inside each Norn.

Interpreting the Science Kit

When you're using the Physical Tab on Science Kit to observe a Norn's biochemistry or investigate a problem with the Norn's health, you'll notice that each organ has a clock rate and a life force. Keep a close eye on the life force for each organ, it will gradually decrease with age but exposure to radiation and heavy metals will greatly reduce the life force of certain organs. Take the bones for example: if a Norn has visited the Volcano and stayed there too long, the radiation may damage his bones. This is not lethal but the radiation will also have damaged his immune system and reduced his ability to reproduce. Zero life force for the heart is lethal, so watch out.

Similarly so, a low life force for the liver is serious as the liver plays a central role in the Norn's biochemistry. The clock rate for each organ is the rate by which the chemical reactions occur. Attached to the outside of each organ are reaction sites where chemicals bind and are converted into other chemicals by enzymes. It's quite normal for clock rates to be quite low. If there's no food in the stomach then the clock rate drops down to 1% even though the Norn is quite healthy. When a Norn has just eaten, the clock rate of the Pancreas Beta is high as it's busy converting excess glucose into long term energy stores. The Pancreas Alpha, on the other hand, will be running at a low clock rate because there's no need to mobilise the energy stores.