The helical reversal structure of natural cellulose shows the
constantly recurring cellobiose unit, consisting of two glucose units
each with six carbon atoms. The length of unit cell along the fibre
axis is 10.4A calculated for the cellobiose unit.
In natural cellulosic fibres there are 3000 - 5000 C6 or glucose
units joined together. This corresponds to a molecular weight of
the order of 300,000 -500,000.
Proteins
Nitrogenous compounds:
- Present in primary cell wall and lumen.
- Yellow colour of cotton is due to presence of proteins and some colouring matter.