Answer to Question 1
Glucose is one sugar that has regulatory elements in metabolism during cell entry and use for energy or fat storage. Sucrose is a disaccharide, made from fructose and glucose. Fructose can bypass two major limiting steps and is preferentially converted to fat in the liver.
Answer to Question 2
The double bond can form two different configurations that dictate how the molecule is shaped in nature, either a relatively straight chain, or a bent chain with a bend at different angles. Figures 3.6 and 3.7 show that a trans double bond (such as the one circled in arachidonic acid) makes a structure that is relatively straight, just like normal saturated fatty acids. A cis double bond, as in oleic and linoleic, forms a bend in the molecule, so that it fills more space because the carbon chains cannot pack together tightly. So in general, unsaturated fatty acids with trans double bonds pack tighter and are more solid than unsaturated fatty acids with cis double bonds. This is one reason why you may have heard or read that trans fats are bad: they are simply much more like saturated fats than unsaturated oils.
An overview of glucose metabolism
D-Glucose Spectrum
Insulin, glucagon, and blood glucose.
Loading of sucrose into phloem.
Hormones Regulate Blood Glucose
Possible Sources of Differences in Output per Worker