Macromolecules lab

Question 1

What molecule would be identified with the Benedict’s test

Answer 1

Monosaccharides
(Carbohydrates)

Positive control - glucose
Result - color copper/brown

Negative - clear blue

Question 2

What would be used as a positive test control (Benedict’s test) & appearance

Answer 2

Glucose
(Copper/red/brown shades)

Question 3

What molecule would be identified with Lugols iodine test

Answer 3

Polysaccharides
(Carbohydrates)

Positive control - starch
Result - black / dark purple color

Negative result - yellow

Question 4

What molecule would be identified with Ninhydrin test

Answer 4

Amino acids (protein)

Positive control - MSG
Result - purple stain

Negative result - dried on paper

Question 5

What molecule would be identified with Biuret test

Answer 5

Polypeptides (protein)

Positive control - albumin
Result - dark purple liquid

Negative result - clear blue

Question 6

What molecule would be identified with the grease spot test

Answer 6

Fatty acids , triglycerides (lipids)

Positive control - vegetable oil
Result - oil stain

Negative result - dries out

Question 7

Positive control + result ( lugols test)

Answer 7

Starch (polysaccharides)
Positive - black/ dark purple

Question 8

Positive control + result ( ninhydrin)

Answer 8

MSG (amino acids)
- purple stain if positive

Question 9

Positive control + result (biurets)

Answer 9

Albumin (polypeptides)
- dark purple liquid if positive

Question 10

Positive control + result (grease spot test)

Answer 10

Vegetable oil ( fatty acids , lipids)

• oil stain if positive

Question 11

Positive test result for Benedict’s

Answer 11

Shades of copper , brown , red
(Glucose - monosaccharides)

Question 12

Negative result for Benedict’s

Answer 12

Clear blue liquid
(Monosaccharides)

Question 13

Positive test result lugols

Answer 13

Dark purple / black
- starch (polysaccharides)

Question 14

Negative test result for lugols

Answer 14

Clear Yellow liquid
(Polysaccharides)

Question 15

Positive test result for Ninhydrin

Answer 15

Purple stain
(Amino acids / MSG)

Question 16

Negative result for Ninhydrin

Answer 16

Dried out / nothing shown on paper
(Amino acids )

Question 17

Positive test result for Biurets

Answer 17

Dark purple color
(Polypeptides/ albumin)

Question 18

Negative test result for biurets

Answer 18

Clear blue liquid
(Polypeptides)

Question 19

Positive test + negative result for grease spot test

Answer 19

Grease stain
(Vegetable oil/ fatty acids)

(negative result dries out )