Benedict"s Reagent: A Test for Reducing Sugars carbohydrate are separated into two groups based upon the complexity of your structure. Simple carbohydrates can form either a single ring framework (monosaccharides) or a double ring structure (disaccharides -- developed when a pair the monosaccharides bond). An easy carbohydrates include familiar sugars together the monosaccharides glucose (the simple fuel of cells) and fructose (found in fruits). Typical disaccharides include sucrose (table sugar) and also lactose (the street in milk). Complex carbohydrates (polysaccharides) room chains of many bonded basic carbohydrates, and are frequently used for energy storage. These encompass starch, cellulose, and also glycogen. One test because that the visibility of many straightforward carbohydrates is to usage Benedict"s reagent. It turns from turquoise to yellow or orange once it reacts with reducing sugars. These are simple carbohydrates with unbound aldehyde or ketone groups. In lab, we used Benedict"s reagent come test for one particular reducing sugar: glucose.
See more: Colin Needs To Borrow 1500 For Car Repairs, Colin Needs To Borrow $1,500 For Car Repairs
Interpreting Benedict"s Reagent Results Benedict"s reagent starts out aqua-blue. Together it is boil in the presence of to reduce sugars, it transforms yellow to orange. The "hotter" the final color of the reagent, the greater the concentration of to reduce sugar. In general, blue to blue-green or yellow-green is negative, yellowish come bright yellow is a center positive, and also bright orange is a very solid positive. (See below).
Terminology review: Controls
Water to add Benedict"s reagent is a negative control for the street test. It demonstrates a an adverse test an outcome (no sugar present). View tube 1 above.
Glucose add to Benedict"s reagent is a positive control because that the street test. It demonstrates what a solid positive an outcome should look like. It also proves the our reagents haven"t gone poor (they are capable of producing a optimistic result). Watch tube 4 above. The suggest of controls is twofold. They offer you standards to compare against, and also they demonstrate that your reagents room working correctly.
Class Benedict"s Reagent Results as well as our controls, us tested three options for glucose: starch, acid-treated starch, and also amylase-treated starch. Together starch is a polysaccharide, that is unsurprising that the starch solution tested an adverse for simple sugars. We combined HCl (an acid) right into starch and re-tested for an easy sugars. First, we had to adjust the pH that the solutions ago to neutral before including the Benedict"s reagent. We provided a pH indicator and NaOH (a base) because that this. Us then included the Benedict"s reagent. We acquired moderately optimistic results (orangish color). This is due to the fact that HCl breaks starch back down right into its component monosaccharides (glucose, in this case). Amylase is one enzyme that removes glucose molecules from starch. Both plants and animals usage amylase as soon as digesting starch. Unfortunately, amylase cannot break the beta-bonds which organize the glucose molecules together in cellulose. (If it could, we"d be able to eat hay). Based upon this information, have the right to you figure out what our results must be if we tested amylase-treated starch and also amylase-treated cellulose options for to reduce sugars?