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.
Alcohols are biomolecules that contain at least one hydroxyl group (RâOH). The simplest of all oxygen-containing functional groups, hydroxyl groups add polarity to organic molecules because of the strong electronegative nature of oxygen atoms. Therefore, unless the remainder of an organic molecule is very large and nonpolar, most alcohols dissolve in water by forming hydrogen bonds.