negative control for the Benedicts reaction? Benedicts test contains REAGENT CUPRIC

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BIOS 1404 Practical 1 Lab 1

• Which one of the solutions is the positive control, and which one of the solutions is the

negative control for the Benedict's reaction? Benedict's test contains REAGENT CUPRIC

COPPER ION

–Answer The positve control are the solutions with monosaccharides with glucose or fructose which changes the color of the solution to either green or reddish orange. The negative control was the solutions that remained blue which was distilled water, potato juice, and 1% starch solution since it doesnt reduce sugars.

• Which contains more reducing sugars, potato juice or onion juice? How do you know?

–Answer onion juice because it reduced to a green color and potato juice remianed blue meaning it doesn't contain any reducing sugars.

• Which one of the solutions is the positive control, and which one of the solutions is the

negative control for the Iodine reaction?–Answer A bluish-black color is a positve test for starch, and a yellowish-brwon color indicates a negative test for starch in the Iodine test.

• Which colors more intensely for the Iodine Reaction, onion juice or potato juice? Why?

–Answer Potato juice because it produced a purplish to blue color indicated that the iodine coiled with the starch polymer.

• Which one of the solutions is the positive control, and which one of the solutions is the

negative control for the Biuret reaction?–Answer A violet purple color indicate a positve test in the Biuret reaction, and a blue color indicates a negative test for the Biuret test.

• Which contains more peptide bonds egg albumin or honey? How do you know?

–Answer 2mL of egg albumin because it produce a lavender purple color reaction indicate it has more peptide bonds that interacted with Cu+. 1 / 2

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• Do free amino acids have peptide bonds?

–Answer No because a peptide bond is a bond between two amino acids.

• What do you conclude about the solubility of lipids in polar solvents such as water compared to

nonpolar solvents such as acetone?–Answer In the distilled water, the lipids did not mix well with the distilled wat which was why there was a semi-solid of lipids that stay on top. In the acetone solution, there was no clear distinction between the lipds and solution because it was clear.

• What happened when the emulsifier was added?

–Answer Bubbles formed and rose to the top of the test tube, there was also a foggy white solution left over

• Which one of the solutions is the positive control, and which one of

the solutions is the negative control for the Sudan IV reaction?–Answer the Positive coontrol was the salad oil and lipid solution. The negative control was the distilled water

• Compare tubes 1 and 3 in the second experiment. What is the distribution of the dye with

respect to the separated water and oil?–Answer In tube 3, the distilled water, the solution was almost fully clear while in tube 1, the salad oil produce a more toned pink after the 5 drops of Sudan iV since it was an oil solution.

• Which one of the solutions is the positive control, and which one of the solutions is the

negative control for the Dische reaction?–Answer the positve control are the solution with DNA solution, which the negative controls are the solutions without DNA solution.

• How does the color compare between tubes 1 and 2? Why?

–Answer In tube 1, the blue color it produce was a cloudy blue, while the blue produce in Tube 2 was a more clear light blue. The reason for this is because in tube 1, the DNA solution was more concentraled than the DNA solution in tube 2, because it was diluted a bit by the distilled water

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