HONORS BIOLOGYTesting Macromolecules

Qualitative

•Detecting if a substance is present•You won’t be determining how much

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

5-6 boiling chips

• Used so the liquid boils smoothly without becoming superheated or bumping

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)

Reference Sheets on the Back CartIodine Test

Fat (lipid) testProtein test

GLUCOSE TEST: Recording Benedict’s Results

• - blue no sugar• + blue/green trace• ++ green little sugar • +++ yellow some sugar• ++++ orange/red much sugar

Benedict’s Glucose Test

Iodine Starch Test

negative

positive

Polysaccharide Disaccharide (sucrose)

Monosaccharide (glucose)

Monomer = glucose

Hydrolysis“break with water”to make monomers

Sucrose, A Disaccharide

• Glucose Fructose

Monosaccharides (Glucose)

• What color is Benedict’s before testing?• What is it used to test the presence of?• glucose

Which tests are positive for glucose?Which sample shows the highest amount of glucose?

Which is a positive test for glucose?

• What do the various colors mean?

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

Which test is positive for starch?

• Add iodine• Look for blue-black color

• 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?

How do glucose molecules and starch molecules compare?

Starch is made of chains of glucose

starch

LIPIDS (fats/oils)

•We will be substituting ULTRA SOY for chicken broth

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.

Does milk have lipids? Does butter?

• Added Sudan IV• Look for red color for (+) test

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

Would this cat make a positive fat test?

What color is Biuret’s at start?How do you know if your sample is positive for protein?

PROTEIN TEST

• DO NOT HEAT PROTEIN TEST

• Will turn from blue to purple on its own

Does milk have protein?

• Added Biuret’s

SUMMARY OF MACROMOLECULE LAB TESTS