PJS - Structural Carbohydrates Flashcards
What is the difference between alpha and beta glucose?
-OH group on C1 is facing down (Alpha)
-OH group on C1 is facing up (Beta)
What are disaccharides?
A molecule containing 2 monosaccharides
What structural carbohydrate is the most abundant polymer on the planet?
Cellulose
What are 3 important structural carbohydrates in plants?
- Hemicellulose- very good at crosslinking
- Pectin- gelling agent in jams
- Agarose- complex polysaccharide
What are 2 important structural carbohydrates in animals?
- Chitin- main component of exoskeleton
- Glycosaminoglycans- Involved in the cell signalling process
What is an important structural carbohydrate in bacteria?
Peptidoglycan- Present in cell walls
Where does N-linked glycosylation occur?
Occurs in the ER (modified in the Golgi)
Where does O-linked glycosylation occur?
Occurs in the Golgi
What molecules are linked in N-linked oligosaccharides?
N-acetyl glucosamine is linked to the -NH2 group of an asparagine
What molecules are linked in O-linked oligosaccharides?
N-acetyl glucosamine is linked to serine, threonine or hydroxyproline
Which Oligosaccharide forms more complex structures?
N-linked is complex
O-linked is simple
What are the main functions of protein modification?
1. Helps proteins fold in the ER (Calnexin and Calreticulin bind oligosaccharide and stop aggregation of proteins)
**2. Helps direct proteins to their final destination ** (Lectins guide proteins from ER to Golgi)
3. Helps protein function (Improved stability and solubility) (Oligosaccharides interact with lectins and function in cell-to-cell adhesion in signalling)
