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.
Hydrocarbons are compounds made from carbon and hydrogen atoms joined by covalent bonds. Alkanes are saturated-they have only single bonds. Alkenes have a double bond-they are unsaturated. Alkenes react with brown bromine water and decolourise it, but alkanes do not.Alkenes can act as monomers. Under high pressure and in the presence of a catalyst many monomer molecules join together to make polymer molecules.lkanes are saturated-they have only single bonds. Alkenes have a double bond-they are unsaturated. Alkenes react with brown bromine water and decolourise it, but alkanes do not.