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.