biochemically, sugar is a group noun, naming a whole raft of compounds.This leads to confusion between people who use different meanings.
The white crystals you buy in 1kilo bags at the supermarket is properly named sucrose. the sucrose molcule is a disaccharide, made up of 2 chemically joined parts, one is glucose,the other fructose.
All are energy storage compounds made in plants by photosynthesis. Glucose is often thought of as the simplest sugar. Actually there are plenty of simpler ones, but Glucose is a simple biologically active organic molecule. Glucose forms white crystals too, which are very soluble in water and taste sweet.Fructose is also a simple sugar. It too forms white crystals, is soluble and sweet, actually a lot sweeter than sucrose. Most fruits store energy as fructose. Grapes contain a lot of Fructose. It doesn't actually raise blood sugar very much or very fast, but there are other issues with it. I won't go into that. I don't want to write a sugar chemistry text-book. Many plants store their glucose by making it into long chains and then folding those chains. That is called starch.
So for anyone who likes big words to coonfuse their HCPs with. Glucose is a hexose monosaccharide,Fructose is a hexose monosaccharide. Glucose forms a 6 carbon ring, where Frucose has 5 carbons in its ring and one elsewhere in the molecule. Sucrose is a disaccharide formed from Glucose and Fructose and starch is a polysaccharide formed of chains called amylose and amylopectin.
Many sugars raise blood suar, if they convert easily to glucose.
note the name key "~ose" if you see this on a chemical name, it usually means a suar and so watch out becareful with it. One exception is sucralose or Splenda, which is a chemically modified sugar and isn't biologically active
Hana