CP Bio B - 05 Indicators - Halloran

Nutrient

A substance needed by an organism to live.
Ex. carbohydrates, proteins, lipids, nucleic acids, water, vitamins and minerals

Essential Nutrient

A substance that is needed by an organism to live that must be obtained from the environment because they cannot make it themselves

Indicator

Used to test for the presence of a certain substance
Ex. iodine is an indicator used to detect starch

Positive Control

Test sample used to show a change in color
Ex. rust colored iodine turns black in the presence of starch

Negative Control

Test sample used to show no change in color
Ex. iodine remains rust colored in the absence of starch

Translucent

Allowing light but not a clear image to pass through

Benedicts Solution

Indicator that tests for sugar. Negative for sugar is bright blue. Positive for sugar is green, yellow, orange.

Iodine

Indicator that tests for starch. Negative for starch is rusty orange. Positive for starch is blue/black.

Biuret Reagent

Indicator that tests for protein. Negative for protein is light blue. Positive for protein is purple.

Brown Paper

Indicator that tests for lipids. Negative for lipid is opaque. Positive for lipid is a translucent spot.