Question

The difference between amylase and amylopectin is __________.
(a)- \[Amylopectin\text{ }have\text{ }1\to 4\alpha -linkage\text{ }and\text{ }1\to 6\beta -linkage\]
(b)- \[Amylopectin\text{ }have\text{ }1\to 4\alpha -linkage\text{ }and\text{ }1\to 6\alpha -linkage\]
(c)- Amylose is made up of glucose and galactose.
(d)- \[Amylose\text{ }have\text{ }1\to 4\alpha -linkage\text{ }and\text{ }1\to 6\beta -linkage\]

Answer 1

Hint: One of the following has the branched-chain structure and one has the linear chain structure. Both of them are made up of glucose components only.

Complete step by step answer:
Starch is not only a single compound but is a mixture of two components-a water-soluble components called amylose (15-20%) and a water-insoluble component called amylopectin (80-85%). The aqueous solution of amylose gives a blue color with an iodine solution. Amylopectin, on the other hand, does not give blue color with iodine solution.
Structure of amylose: It is a linear polymer of \[\alpha -D-glu\cos e\] in which\[{{C}_{1}}\] of one glucose unit is attached to\[{{C}_{4}}\] of the other through\[\alpha -gly\cos idic\] linkage.

Structure of amylopectin: Amylopectin, on the other hand, is a highly branched polymer. It consists of a large number of short chains each containing 20-25 glucose units which are joined together through \[\alpha -gly\cos idic\] linkage involving \[{{C}_{1}}\] of one glucose unit with\[{{C}_{4}}\] of the other. The \[{{C}_{1}}\]of the terminal glucose unit in each chain is further linked to\[{{C}_{6}}\] of some other glucose unit in the next chain through \[{{C}_{1}}-{{C}_{6}}\]\[\alpha -gly\cos idic\] linkage. This gives amylopectin a highly branched structure.


Hence, from the above discussion option (b) is correct.

Note: You may get confused between \[\alpha -linkage\] and \[\beta -linkage\]. \[\alpha -linkage\] is formed when the bond is formed on the same side and \[\beta -linkage\]is formed when the bond is formed between the opposite side.