Question

activity: biological tests
medical laboratory technicians often conduct tests to determine the presence of various molecules in mud, blood, or urine. here is your chance to review your knowledge of carbohydrates, lipids, and proteins, and to test for their presence in various foods.
go to your course page on the hc website and click on \biological tests\ under lesson. read the introduction. in part 1, conduct the test for glucose and starch. in part 2, conduct the test for lipids. in part 3, conduct the test for protein. now answer the following support questions.
support questions

1. match each item listed on the right with correct description on the left:

simple molecule that joins to form polymers
large molecule formed by many repeating identical or similar monomers
monomer of starch
monomer of protein
made of three fatty acids bonded to a molecule of glycerol
a. amino acid
b. fat or oil
c. glucose
d. monomer
e. polymer

1. complete the following chart:

solution	nutrient solution tests for	how to tell when the nutrient is present	example of a substance that contains the nutrient
benedicts solution
iodine
biuret solution
sudan iv solution

Explanation:

1. A monomer is a simple molecule that joins to form polymers.
2. A polymer is a large molecule formed by many repeating identical or similar monomers.
3. Glucose is the monomer of starch.
4. Amino - acid is the monomer of protein.
5. Fat or oil is made of three fatty acids bonded to a molecule of glycerol.

For the chart:

• Benedict's solution tests for reducing sugars like glucose. A positive test is indicated by a color change from blue to green, yellow, orange or red. An example is apple juice.
• Iodine tests for starch. A positive test results in a color change to a deep blue - black. An example is a potato.
• Biuret solution tests for proteins. A positive test is shown by a color change from blue to violet. An example is egg white.
• Sudan IV solution tests for lipids. A positive test causes the lipid to stain red. An example is butter.

Answer:

27.

• Simple molecule that joins to form polymers: D. Monomer
• Large molecule formed by many repeating identical or similar monomers: E. Polymer
• Monomer of starch: C. Glucose
• Monomer of protein: A. Amino acid
• Made of three fatty acids bonded to a molecule of glycerol: B. Fat or oil

28.

Solution	Nutrient solution tests for	How to tell when the nutrient is present	Example of a substance that contains the nutrient
Iodine	Starch	Color change to deep blue - black	Potato
Biuret solution	Proteins	Color change from blue to violet	Egg white
Sudan IV solution	Lipids	Lipid stains red	Butter