The structural of Polysaccharides of the cell wall and how they studied

- primary surrounding growing cells: polysaccharides: cellulose hemicelluloses and pectins, some structure of protein
- secondary walls: stopped growing, #, polysaccharides and proteins, lignin, extra amounts of cellulose.
- cellulose is type of polysaccharides
- glycosyl and

 glucosyl

Starches

Starches are glucose polymers in which glucopyranose units are bonded by alpha-linkages. It is made up of a mixture of Amylose (15–20%) and Amylopectin (80–85%). Amylose consists of a linear chain of several hundred glucose molecules and Amylopectin is a branched molecule made of several thousand glucose units (every chain of 24–30 glucose units is one unit of Amylopectin). Starches are insoluble in water. They can be digested by hydrolysis, catalyzed by enzymes called amylases, which can break the alpha-linkages (glycosidic bonds). Humans and other animals have amylases, so they can digest starches. Potato, rice, wheat, and maize are major sources of starch in the human diet. The formations of starches are the ways that plants store glucose.

PDs: degree of polymerizations: is usually defined as the number of monomeric units
Determination the primary structure of a polysaccharides:
1. Glycosyl redidue composition 
 2. The absolute configuration, D or L of each glycosyl residue.
The process of  characterization of polysaccharides is involved
- Methylation: Using hakomori methylation method
- Hyrolysis: TFA and myo-inositol at 120oC
- Reduction: Mark C1 to Deuterium by NaBrD4
- O-acetylation:
- GC-MS
The preparation of Potassium dimethysulphinyl anion


- add ~15mL hexane while stirring, to dissolve hydrocarbon in oil
- Stop stirring allows KH to settle
- Carefully remove the top hexane layer, add it to beaker containing excess of ethanol(quenches traces KH)
Repeat wash 5X
keep Nitrogen flows until dry powder is obtained.
- Add 10mL of dry DMSO(99%)dropwise (10-15min), stirring for 30min until a light greenish-brown solution is obtained.
- Transfer ~1mL of reagent to serum vials and seal them with Teflon-lined caps.
Store for several month over drierite at -20C.
Preparation of  Lithium dimethylsuphinyl anion