What are the advantages to using a wet mount preparation?

• The specimen could be viewed moving
• The specimen's behavior can be viewed as they interact with the environment
• The specimen may be alive

Benedict Test for Sugar

• A positive result occurs anytime the reagent changes from its original blue color. Relative concentration of simple sugar can be determined by color.
• Blue represents the lack of simple sugars. The color then progresses through green, orange, and red as the amount of simple sugars increases.
• The reaction requires heat to take place

Glucose

A small, six-carbon sugar molecule found in starch and glycogen. A common monosaccharide.

Monosaccharide

One individual molecule of sugar; the building blocks of carbohydrates.

Disaccharide

A carbohydrate made up of two sugar molecules linked together.

Maltose

A disaccharide consisting of two glucose molecules bound together.

Simple Sugar

Monosaccharides and disaccharides.

Oligosaccharide

A carbohydrate made up of more than two sugar molecules linked together.

Polysaccharide

A carbohydrate made up of hundreds to thousands of sugar molecules linked together.

Starch

A plant-based polysaccharide.

Glycogen

An animal-based polysaccharide.

Iodine is used to test for:

• Starch
• A positive test result for starch occurs when iodine turns color.
• Medium blue is a small amount of starch, dark blue indicates a medium amount of starch, and blue-black indicates a large amount of starch.
• A negative test result for starch occurs when iodine stays yellow.

Positive Control

Any procedure that is known to produce the desired result. A positive test result means what you are looking for is present.

Negative Control

Any procedure that is known to NOT produce the desired result. A negative test result means what you are looking for is NOT present.

Iodine

Is a yellowish-brown colored liquid that turns blue or black when it contacts starch.

Glucose and starch are both carbohydrates. Why does glucose produce a negative result when testing using iodine?

Iodine only tests for polysaccharides, and glucose is a monosaccaride

The Biuret test helps to detect?

• Proteins
• A positive result occurs anytime the reagent changes from its original blue color to a pink or purple color.
• Any tube that is blue, no matter which shade of blue, does not contain protein.

Proteins

Polymers consisting of long chains of amino acids

Monomer

A substance that is the smallest unit of a category of substances. For example, an amino acid is a monomer of a protein.

Polymer

A substance made up of many units of a common chemical attached to each other.

Biuret Reagent

A light blue reagent that tests for protein

What is the most common type of lipid?

Triglycerides

Lipid

A macromolecule made up of dozens to hundreds of molecules of mostly carbon and hydrogen.

Cholesterol

A lipid with a structure containing over 20 carbon atoms configured into four rings

Phospholipid

A lipid made up of a three-carbon glycerol molecule with a phosphate group and two fatty acids

Triglyceride

A lipid made up of a three-carbon glycerol molecule with three fatty acid chains attached to it

Fatty Acids

Long chains of carbon with hydrogen attached, making them nonpolar molecules

Saturated Fatty Acid

A chain of carbon atoms using only single carbon-to-carbon bonds with hydrogen atoms attached to the carbon atoms

Unsaturated Fatty Acid

A chain of carbon atoms that contain one (monounsaturated) or more (polyunsaturated) double bonds between carbons with hydrogen atoms attached to the carbon atoms

How to interpret the paper test:

• A positive result for a lipid will result in an evenly distributed oily stain remaining on paper after 15 minutes.
• Water will completely evaporate, and nonlipid substances mixed with water will leave a circular stain.