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Experiment 3. Trommer's test for ribose.
Place 5–6 drops of yeast
hydrolyzate and 5–6 drops of 10% NaOH solution in a test tube. Add 1 drop of
2% solution of CuSO
4
to the resulting mixture, and water to 2 ml. Heat the top
of the test tube over the flame of the alcohol lamp, but do not boil. What are
you observing? Write the equation for the reaction of ribose with copper (II)
hydroxide.
Experiment 4. Detection of phosphoric acid.
Add 1 ml of solution
(NH
4
)
3
MoO
4
in nitric acid to 1 ml of yeast hydrolyzate, and heat. What are you
observing? The reaction is based on the formation of a crystalline precipitate of
ammonium phospho-molybdate:
PO
4
3-
+ 3NH
4
+
+12MoO
4
2-
+ 24H
+
→ (NH
4
)
3
[PMo
12
O
40
]↓ +12H
2
O
LESSON 26.
FINAL CONTROL № 4
Final control number 4 is conducted on the following topics:
1. Chemistry of amino acids.
2. Chemistry of peptides and proteins.
3. Chemistry of nucleic acids.