Out here in the stroma, a bunch of different enzymes use the carbon dioxide molecules and hydrogen ions made during the light dependent phase to assemble sugar fragments which are half of a glucose molecule (just 3 carbon atoms, instead of the 6 required to make a complete glucose molecule).
An alkane, by definition, only has single bonds. Even if your second diagram made sense (it doesn't for the reason above) it would not be an alkane at all because there is a double bond. Alkanes are a functional group. It's called alkil. As a functional group they have the generic formula R(CH2)nH.
In organic chemistry, functional groups are specific groups (moieties) of atoms or bonds within molecules that are responsible for the characteristic chemical reactions of those molecules.roups containing halogens [edit]. Haloalkanes are a class of molecule that is defined by a carbonâ halogen bond. This bond can be relatively weak (in the case of an iodoalkane) or quite stable (as in the case of a fluoroalkane).