This lesson includes 24 additional questions for subscribers.
Lesson Worksheet: The Chemistry of Food Biology
In this worksheet, we will practice describing how to carry out chemical tests on food to determine the presence of sugars, starch, protein, and fats.
Complete the table to show the correct biological molecule being tested for, or the name of the test.
|Molecule Being Tested for||Starch||2||Protein||4|
|Name of Reagent/Test||1||Ethanol/Emulsion test||3||Benedict’s solution|
- A1: Iodine, 2: Sugars, 3: Biuret, 4: Lipids
- B1: Biuret, 2: Sugars, 3: Iodine, 4: Carbohydrates
- C1: Iodine, 2: Lipids, 3: Biuret, 4: Sugars
- D1: Biuret, 2: Lipids, 3: Iodine, 4: Sugars
- E1: Biuret, 2: Sugars, 3: Iodine, 4: Lipids
Proteins are polymers. What monomers are they made from?
- AFatty acids
- DAmino acids
A banana was tested for different food groups and the results are shown below.
|Reagent Added/Test Performed||Iodine||Benedict’s||Biuret|
|Result||Blue black||Brick red||Light purple|
Which of the following is the correct conclusion about the biological molecules found in the banana?
- AThe banana contains starch, sugar, and some protein.
- BThe banana contains starch and sugar but no protein.
- CThe banana contains neither starch, sugar, nor protein.
- DThe banana contains starch but neither sugar nor protein.
Complete the statements to correctly describe the composition of the biological molecules.
A protein is made of many monomers called .
- Afatty acids
- Bamino acids
Many sugar molecules, like glucose, join together to form .
A basic lipid molecule is formed of one and three fatty acids.
- Damino acid
Two samples of food have been tested with the emulsion test. What are the biological molecules contained in sample Y, according to the demonstrated results?
- AReducing sugars
An egg yolk was tested for different food groups and the results are provided.
|Reagent Added/Test Performed||Iodine||Benedict’s||Biuret||Emulsion|
|Result||Orange||Blue||Purple||White emulsion layer|
According to these results, which of the following is the correct conclusion about the biological molecules found in the egg yolk?
- AThe egg yolk contains sugars and starch, but not protein.
- BThe egg yolk contains fats and proteins, but neither starch nor sugars.
- CThe egg yolk contains starch, sugars, protein, and fats.
- DThe egg yolk contains sugars and proteins, but neither starch nor fats.
When carrying out the test for reducing sugars using Benedict’s reagent, the mixture should be heated in a water bath. Why should a water bath be used, rather than a Bunsen burner?
- AIt is too dangerous to use a Bunsen burner near Benedict’s reagent.
- BA Bunsen burner should only be used to heat up water, not other mixtures.
- CIt is easier to maintain a constant temperature when using a water bath.
- DA Bunsen burner will not reach the required to heat the mixture.
- EThis is incorrect; a Bunsen burner should be used.
Carbohydrates are polymers. What monomers are they made from?
- BAmino acids
- CSimple sugars
- DFatty acids