Calvin cycle

Carbon fixation and the Calvin cycle

These are the things covered by the photosynthesis tutorial.

The biochemical reactions, also known as the light independent reactions of photosynthesis link CO2 to a pre-existing molecule of RuBP.

This reaction is catalyzed by the enzyme, Rubisco. Rubisco is probably the most important enzyme in the world (quantitatively and qualitatively).
This reaction is also known as carbon fixation because the carbon from CO2 is taken from a gas and "fixed" into something more substantial.
The initial products are smaller molecules with more total carbon atoms than RuBP because of the additional carbon in CO2.

But they have less actual energy stored in them. Reactions which transfer energy from two storage compounds (ATP and NADPH) convert the low energy compounds in to high energy ones that can fuel all sorts of other processes, both in plants and in the things that eat them.

These are called carbohydrates. They can leave the chloroplast across its membranes. All the rest of life depends essentially on their conversion into other products, or their respiration to release stored energy for other processes.
The chemical change that occurs is technically a "reduction reaction" so this storage of energy is called carbon reduction, or simply "conversion".

Some of the carbohydrates, about 5 in every 6 that are formed, are converted back to RuBP so the process can continue. The other one is available for whatever else the plant has in mind.

This phase of the process is called "regeneration" because the RuBP is regenerated.

Because this pathway makes both the product (carbohydrates and the initial substrate, it is called autocatalytic. That means it catalyzes, or encourages, itself... it is a real self-starter!
Follow this link for a closer look at how these numbers work(*).

More help with the terminology!

Carbohydrate -: A compound that contains carbon, hydrogen, oxygen and nothing else. Generally, the number of carbon and oxygen atoms is the same and there are twice as many hydrogens.. i.e. the formula for carbohydrates is some multiple of CH2O. Sugars are one type of carbohydrate. Their names usually end in "-ose"; triose-phosphate (triose-P) is the name give to a 3 carbon sugar which is the first real sugar produced by photosynthesis.
Catalyst -: In chemistry, this is a chemical that speeds up a reaction without actually taking part in it. Enzymes are a kind of proteins that make some very complicated reactions possible... they catalyze the reactions. You can also think of machines, say a trash compactor, as catalysts... the trash would never get squished up if the machine did not act on it.
Energy -: In biology, energy means chemical energy, the stuff that fuels life. Energy can be "extracted" from almost any compound in a living organism. But in pretty much all cases, it ends up being stored for some period of time in easily used, rapidly recycled compounds. Two of these are called ATP and NADPH.
Pathway -: In biochemistry, a pathway is a group of linked reactions. A starting compound (or substrate) is converted to something else (a product) and so on down some group of paths until a destination is reached... i.e. a "final" product. Of course, since almost anything can be made into something else, there aren't many really final products.
RuBP -: The chemical to which CO2 is fixed in photosynthesis. It stands for "ribulose 1,5-bisPhosphate" which tells you it is sugar called "ribuloae", and it has two phosphate molecules attached to it... in this case at opposite ends.
Rubisco -: This is an enzyme that makes the reaction which links RuBP and CO2 possible. The name actually is a short version of "ribulose 1,5 bisPhosphate carboxylase/oxygenase". The "ase" parts of the name mean the protein is an enzyme, a machine. The other bits tell you what it does. It sounds like the name of a breakfast cereal and cracker maker, but it isn't.