AP BIOLOGY

Detailed explanation-1: -Iodine solution is used to test leaves for the presence of starch. You need to: heat a plant leaf in boiling water for 30 seconds (this kills the leaf, stopping any chemical reactions)

Detailed explanation-2: -Iodine solution is used to test the presence of starch in samples. With starch, iodine turns blue-black in colour. In the case of a variegated leaf, only green parts can trap sunlight and produce starch during photosynthesis whereas the non-green parts cannot.

Detailed explanation-3: -Iodine patch test: The iodine patch test is a test where doctors paint a patch of iodine on your skin and check how it looks 24 hours later. For those who are not iodine deficient, the patch fades no sooner than 24 hours. But a deficiency will likely cause the iodine to be absorbed into the skin more quickly.

Detailed explanation-4: -Iodine-KI Reagent: Iodine is not very soluble in water, therefore the iodine reagent is made by dissolving iodine in water in the presence of potassium iodide. This makes a linear triiodide ion complex with is soluble that slips into the coil of the starch causing an intense blue-black color.