Topic 1 *

• Glycogen is a polysaccharide of glucose and has a highly branched structure.
• An optical light microscope uses light while a transmission electron microscope uses electrons. Therefore a light microscope has a lower resolution so cannot see organelles as small. A transmission electron microscope can only see dead specimens, requires thinner specimens, does not show colour, requires a more complex preparation process and sometimes produces artefacts.
• Glucose, fructose and galactose are monosaccharides. Sucrose, maltose and lactose are disaccharides. Starch, cellulose and glycogen are polysaccharides.
• Maltose is made from two glucose molecules. Lactose is made from glucose and galactose. Sucrose is made from glucose and fructose. They can be added to polypeptides in the golgi apparatus.
• Starch is made from both amylose (1-4 bonds) and amlyopectin (1-4, and 1-6). Amylose is an unbranched helix while amylopectin is a branched molecule.