Transcript Chemické zloženie

The chemical composition of
biological systems
(nucleic acids, proteins, lipids,
sacharids)
1. The proof of proteins in egg
white and in yeast – biuret
reaction
• Material and methods: 3 test tubes, test tube rack,
pipettes, mortar and pestle, destilled water, 10% KOH,
5% CuSO4, yeast (Saccharomyces cerevisiae), egg
white.
• 1, cca 0,5g of yeast is crushed in mortar with couple of
drops of water, mass is moved to the test tube with
1,5cm3 of water.
2, To the second test tube, we pipette 1,5cm3 of destilled
water.
3, To the third test tube, 0,5 cm3 of egg white is diluted
with saline (1:20) and filled with destilled water to 1,5
cm3.
• Then we add to all three test tubes 1 cm3 of KOH, mix,
add few drops of CuSO4. We observe changes of color.
–
•
•
2. The proof of the amylum
grains in the potato cells
and proof of sacharides in
fruit
amylum-presence test
Material and methods: potato, filter paper, razor blade, Lugol‘s
solution, microscope.
– piece of potate is rinsed with water, using the razor blade we cut
thin slice and move it to microscope slide, we add drop of water.
After short examination we add Lugol’s solution.
2. The proof of amylum
grains in potato cells and
proof of sacharides in fruit
•
sacharides-presence test
– Material and methods: fruit juice, Fehling’s reagent I.
and II.
– – we mix 1+1ml Fehling’s reagent and 2ml juice
(1:1), we slowly heat the substance in water bath.
We observe the change of color.
t= cca 50°C
+
3. The observation of animal fat
in subcutaneous tissue – lipidpresence test
• Material and methods: animal subcutaneous fat,
sudan III solution, microscope
• – we cut thin slice from frozen bacon, we put in
on microscope slide with drop of sudan III
solution. We wait 5-10 minutes. After 10
minutes, we observe the slide under
microscope.