HONORS BIOLOGY Testing Macromolecules. Qualitative Detecting if a substance is present You won’t...
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Transcript of HONORS BIOLOGY Testing Macromolecules. Qualitative Detecting if a substance is present You won’t...
SAFETY
• Must wear goggles and aprons the whole time!!!!!!• If the chemicals react with
proteins, they will react with you.• Iodine stains.
SAFETY
• Cut onion and potato into diced pieces• Rinse razor blades under water, do
not wipe across the blade• Put used blades at the end of the
period in the “used razor blades” container on the cart
Controls
• Positive Control• Absolutely expect
to see the result• Use the substance(starch, glucose,
etc.)
• Negative Control• Absolutely expect
to NOT see the result
• (may use water)
GLUCOSE TEST: Recording Benedict’s Results
• - blue no sugar• + blue/green trace• ++ green little sugar • +++ yellow some sugar• ++++ orange/red much sugar
Monosaccharides (Glucose)
• What color is Benedict’s before testing?• What is it used to test the presence of?• glucose
Iodine is what color at start?Which test tube below is a positive test?
Which is the control?
• Left is potato starch Right is distilled water
• Would you say the iodine and potato (left) is a positive or negative test?
• Would you say the iodine and onion (right) is a positive or negative test?
Sudan IV and MilkDone as a demo because may cause cancer in large amounts
• Sudan IV is an animal mutagen and a potential carcinogen. It must never be handled by staff who are pregnant. It is highly toxic by the intravenous route but has not been quantified through other routes. It is an eye and respiratory tract irritant.
Come to the front teacher test for the results.
Sudan IV turns fats redCan you tell where the fat and where the water
is in this test tube?
See the redder area on top in the right test tube. That is the cream floating on top.
Is this a positive or negative fat test?
• Before After drying
• PositiveYou are looking for translucence: light being able to show through paper.
We will use a paper towel divided into nine sections to test for fats.
Potato Ultra Soy Unknown A
Onion Distilled Water Unknown B
cream Oil Unknown C