In this section we will discuss the synthesis and degradation of storage carbohydrates within a cell. For medically minded people, these processes are used to balance blood glucose levels within humans (and most mammals). First we need to familiarize ourselves with the nomenclature.
|Maltose and trehalose, both made|
from two glucose molecules:
maltose has an α(1→4) bond,
trehalose has an α(1→1)α bond.
Monosaccharides are the simplest carbohydrates. What's a carbohydrate? Carbo- containing carbon; hydrate - a compound in which water (H2O) is bound to other elements; hence CX(H2O)X, where X > 3 (typically), is the chemical formula for most carbohydrates. Examples include glucose, fructose, galactose, etc..
Disaccharides are two monosaccharides linked together, remember your greek δίς - two. Disaccharides form via dehydration (the removing of a water molecule), and can be linked on any hydroxyl group (-OH). This results in several types of compounds being possible from the same two monosaccharides.
Polysaccharides would obviously contain many individual monosaccharides linked together.
To form very complex carbohydrates it is necessary to put branches in this ever-growing chain of monosaccharides.
Ok, now on to the show.
- Only small portions of glucose-6-phosphate are diverted to either of these paths
- The yeast will utilize glycogen during lag phase for its sole carbon source while it trys to reach equilibrium with the external osmotic pressure
- Trehalose is vital for yeast health, especially when put under external temperature stress or changes in osmotic pressure