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Questions and Answers
What is the term used to describe the four classes of biological molecules?
What is the term used to describe the four classes of biological molecules?
Which type of molecules are composed of nucleotides?
Which type of molecules are composed of nucleotides?
What is the purpose of the Benedict's Test?
What is the purpose of the Benedict's Test?
What is the result of the reaction between cupric ions and certain sugars in the Benedict's Test?
What is the result of the reaction between cupric ions and certain sugars in the Benedict's Test?
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What are the main components of lipids?
What are the main components of lipids?
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What is the term used to describe the building blocks of carbohydrates?
What is the term used to describe the building blocks of carbohydrates?
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Which of the following is an example of a nucleic acid?
Which of the following is an example of a nucleic acid?
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What is the color of the Benedict's solution?
What is the color of the Benedict's solution?
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What is the result of heating the Benedict's solution with certain sugars?
What is the result of heating the Benedict's solution with certain sugars?
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What is the primary source of carbohydrate in our diets?
What is the primary source of carbohydrate in our diets?
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What is the result of a positive starch test?
What is the result of a positive starch test?
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What is the function of copper sulfate in the Biuret reagent?
What is the function of copper sulfate in the Biuret reagent?
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What is the minimum number of linked amino acids required for a positive Biuret test?
What is the minimum number of linked amino acids required for a positive Biuret test?
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What is the result of a negative Biuret test?
What is the result of a negative Biuret test?
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What is the purpose of the Sudan IV test?
What is the purpose of the Sudan IV test?
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What is the characteristic of lipids in an aqueous solution?
What is the characteristic of lipids in an aqueous solution?
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What is the result of a positive Sudan IV test?
What is the result of a positive Sudan IV test?
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Why are positive and negative controls important in the Sudan IV test?
Why are positive and negative controls important in the Sudan IV test?
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What happens to the Sudan reagent in a solution with lipids?
What happens to the Sudan reagent in a solution with lipids?
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Lipids are made up of chains of amino acids.
Lipids are made up of chains of amino acids.
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All carbohydrates are reducing sugars.
All carbohydrates are reducing sugars.
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Nucleic acids are composed of amino acids.
Nucleic acids are composed of amino acids.
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Benedict's solution is colorless.
Benedict's solution is colorless.
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A positive Benedict's test is indicated by a blue color.
A positive Benedict's test is indicated by a blue color.
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Copper (I) oxide is formed when cupric ions react with certain sugars.
Copper (I) oxide is formed when cupric ions react with certain sugars.
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Macromolecules have the same structure and function in the body.
Macromolecules have the same structure and function in the body.
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Glycerol is a type of carbohydrate.
Glycerol is a type of carbohydrate.
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A reddish precipitate of copper (I) oxide is formed when cuprous ions react with certain sugars.
A reddish precipitate of copper (I) oxide is formed when cuprous ions react with certain sugars.
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Disaccharides always react with Benedict's reagent.
Disaccharides always react with Benedict's reagent.
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Starch is a type of protein.
Starch is a type of protein.
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Iodine is used to detect the presence of protein.
Iodine is used to detect the presence of protein.
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Biuret reagent reacts with peptide bonds to produce a yellowish-brown color.
Biuret reagent reacts with peptide bonds to produce a yellowish-brown color.
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Free amino acids will react with Biuret reagent.
Free amino acids will react with Biuret reagent.
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Sudan IV is soluble in water.
Sudan IV is soluble in water.
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A negative Sudan IV test result is indicated by a slightly darker red-orange color.
A negative Sudan IV test result is indicated by a slightly darker red-orange color.
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Lipids have a higher density than water.
Lipids have a higher density than water.
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A positive control is not necessary in the Sudan IV test.
A positive control is not necessary in the Sudan IV test.
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The iodine test is used to detect the presence of protein in a solution.
The iodine test is used to detect the presence of protein in a solution.
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Study Notes
Biological Molecules
- Living organisms are composed of molecules with diverse shapes and forms.
- The four main classes of biological molecules are carbohydrates, proteins, lipids, and nucleic acids.
Carbohydrates
- Complex carbohydrates are made up of monosaccharides.
- Some sugars, known as reducing sugars, contain free aldehyde or ketone groups.
- Reducing sugars can be detected using Benedict's Test.
Benedict's Test
- Benedict's solution is blue and contains cupric ions.
- When heated, cupric ions react with certain sugars, forming an insoluble reddish precipitate of copper (I) oxide.
- The solution changes color from blue to green to reddish brown depending on the amount of sugar present.
Starch
- Starch is a polysaccharide produced by plants to store sugars for later energy needs.
- Starch is a primary source of carbohydrate in our diets.
- Starch interacts with iodine to produce a bluish-black color.
Proteins
- Proteins are made up of chains of amino acids.
- Biuret reagent is used to test for the presence of protein.
- Biuret reagent contains copper sulfate, which reacts with peptide bonds, resulting in a violet/lavender color.
- Only proteins with four to six linked amino acids will react with Biuret reagent.
Lipids
- Lipids vary in composition, but main components include fatty acids and glycerol.
- Sudan IV test is used to detect the presence of lipids.
- Sudan IV is not soluble in water but is soluble in lipids.
- If lipids are present, the Sudan reagent will stain the oil droplets a slightly darker red-orange color.
Biological Molecules
- Living organisms are composed of molecules with diverse shapes and forms.
- The four main classes of biological molecules are carbohydrates, proteins, lipids, and nucleic acids.
Carbohydrates
- Complex carbohydrates are made up of monosaccharides.
- Some sugars, known as reducing sugars, contain free aldehyde or ketone groups.
- Reducing sugars can be detected using Benedict's Test.
Benedict's Test
- Benedict's solution is blue and contains cupric ions.
- When heated, cupric ions react with certain sugars, forming an insoluble reddish precipitate of copper (I) oxide.
- The solution changes color from blue to green to reddish brown depending on the amount of sugar present.
Starch
- Starch is a polysaccharide produced by plants to store sugars for later energy needs.
- Starch is a primary source of carbohydrate in our diets.
- Starch interacts with iodine to produce a bluish-black color.
Proteins
- Proteins are made up of chains of amino acids.
- Biuret reagent is used to test for the presence of protein.
- Biuret reagent contains copper sulfate, which reacts with peptide bonds, resulting in a violet/lavender color.
- Only proteins with four to six linked amino acids will react with Biuret reagent.
Lipids
- Lipids vary in composition, but main components include fatty acids and glycerol.
- Sudan IV test is used to detect the presence of lipids.
- Sudan IV is not soluble in water but is soluble in lipids.
- If lipids are present, the Sudan reagent will stain the oil droplets a slightly darker red-orange color.
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Description
This quiz covers the four major classes of biological molecules, including carbohydrates, proteins, lipids, and nucleic acids, and their building blocks.
