MODULE 2-BIOMOLECULES PETA-WORKSHEET-answer Key
MODULE 2-BIOMOLECULES PETA-WORKSHEET-answer Key
MODULE 2-BIOMOLECULES PETA-WORKSHEET-answer Key
Answer Key
ORGANIC MOLECULES
1. How are organic molecules related to all living things? They are life’s building blocks
2. Name four categories of organic molecules which form the basis of all living things.
a. Carbohydrates c. Proteins
b. Lipids d. Nucleic Acid
5. How are the building blocks of organic molecules like bricks? They are joined together to form
large molecules (polymer)
6. What is the building block of each of the four classes of organic molecules?
Carbohydrate---sugar Lipids—fatty acids
Protein-amino acids Nucleic acid-nucleotie
7. What is a polymer? A combination of small molecules (monomers)
8. What determines how organic molecules will look and behave? their shape determines how they will
behave and how they will react with other molecules
There are three classes of carbohydrate polysaccharides. The first is starch. Starch is a carbohydrate
used in food storage in plants. Potatoes, pasta and rice are rich in starch. Starches are very valuable
because they provide a quick form of energy for the body. The second is glycogen. Glycogen is used for
food storage in animals. The third is cellulose. Cellulose is used for structural support in plants (stems,
leaves).
18. Why would an athlete have a big pasta dinner the night before a race? To maximize the storage of
carbohydrate (glycogen) in the body.
Sugars can be detected in foods through a simple lab test. To find out if a food contains starch, iodine (a
reagent) is placed on the food. A food containing starch will turn black when in contact with iodine. A test
for simple sugars involves mixing the food with a liquid blue reagent called Benedict’s solution and then
heating the mixture. If the food is positive for simple sugars, the heating process will cause the benedict’s
solution to turn red, orange, or green.
19. What reagent is put into food to identify the presence of starch? Iodine
20. Describe how someone would be able to identify if a sugar is present in food. A test for simple sugars
involves mixing the food with a liquid blue reagent called Benedict’s solution and then heating the
mixture. If the food is positive for simple sugars, the heating process will cause the benedict’s
solution to turn red, orange, or green.
27. Explain the solubility of lipids. When mixed with water, the lipids will float on top to form a separate
layer.
28. How would you test for lipids, and what is a positive result? To test for the presence of lipids in food,
the sample is placed on a piece of brown or newspaper, and then the paper is held up to the light.
A test that is positive for lipids will have a oily spot that is translucent, or clear, on the paper.
31. What is the name of the bond that joins amino acids? Peptide bond
There are about 20 different kinds of amino acids. These amino acids consist of five separate parts. The
first is a central carbon atom. Second is a carboxyl group (-COOH). Third is an amino group (-NH2).
Fourth is a hydrogen. The fifth group is a variable ‘R’ group. The only difference in the 20 kinds of amino
acids is the “R” group. Some “R” groups are very small, others are large, and even others form chains
and rings. The sequence and shapes of the “R” groups control the shape and function of the protein.
40. Describe the structure and shape of DNA. Twisted ladder/double helix
42. How are the rails of the ladder kept together? The four bases.