AP BIOLOGY

Detailed explanation-1: -Starch Test: Add Iodine-KI reagent to a solution or directly on a potato or other materials such as bread, crackers, or flour. A blue-black color results if starch is present. If starch amylose is not present, then the color will stay orange or yellow.

Detailed explanation-2: -The presence of starch in leaves can be tested by the Iodine test. When we remove chlorophyll from the leaf by boiling it in alcohol and then putting two drops of iodine solution, it is a colour change to blue indicates the presence of starch.

Detailed explanation-3: -The iodine test is a chemical test used to distinguish mono-or disaccharides from certain polysaccharides like amylase, dextrin, and glycogen. This test has a variation termed starch-iodine test that is performed to indicate the presence of glucose made by plants in the leaves.

Detailed explanation-4: -Test to confirm the presence of carbohydrate (starch) Put 2-3 drops of iodine solution on it. Observe the colour of the food item. Change of colour in the food item into blue-black indicates the presence of starch in the food item.

Detailed explanation-5: -The basis for this test is that starch is a coiled polymer of glucose-iodine interacts with these coiled molecules and becomes bluish black. Iodine does not react with other carbohydrates that are not coiled, and remains yellowish brown.