Question

The starch is insoluble in water, still it is stored in potato in more quantity
A. By microbes
B. Because it is manufactured in tuber
C. Because plants use it as food
D. Because first, it comes to the tuber as a sugar solution then it is stored as starch.

Answer 1

Hint: Starch is a polysaccharide made up of glucose. It differs from cellulose only in the linkage between individual glucose units. In cellulose, it is beta linkage but in starch, it is alpha linkage.

Step by step answer:Plants produce food through photosynthesis. It is produced as glucose in leaves. But the food is stored as starch. In most plants, food is transported as sucrose which is formed by combining a glucose and fructose molecule. In some plants, their stem is modified for certain functions. They can be permeation or vegetative propagation. Both underground and aerial types of the stem can be modified in this manner. Stem modifications are of different kinds. Underground stems are modified for storage of food. They are of four types. They are rhizome, corm, stem tuber, and bulb. Potato is an example of a stem tuber whose underground stem is modified for food storage in the form of starch. The subaerial stem is modified mainly for vegetative propagation. They are Runner, Offset, Sucker and Stolon. Stem tubers like potatoes contain a large amount of parenchyma tissues that can store starch. Food reaches the tuber as a sugar solution and here, it is converted into starch. Most tubers pose several buds that can grow into a new plant.
Hence, the correct answer is option D

Note: Iodine test is conducted for finding the presence of starch. If we conduct iodine tests in potatoes, we get positive results as potatoes contain large amounts of starch. When iodine is applied to a potato, it changes its colour to black.