How To Do Test Corrections
When doing test corrections you must explain why your incorrect choice was wrong AND why the correct choice was correct. You should elaborate on your explanations so that I can tell that you have a thorough understanding of the material.
Here are some examples of test corrections that are done the right way and the wrong way. See if you can tell why examples 1 and 2 are bad, and why examples 3 and 4 are good!
25. Which of the following is true both of starch and of cellulose?
a. They are both polymers of glucose.
b. They are geometric isomers of each other.
c. They can both be digested by humans.
d. They are both used for energy storage in plants.
e. They are both structural components of the plant cell wall.
Example 1
Wrong (d) Cellulose is not used for energy storage in plants
Right (a) Starch and cellulose are both polymers of glucose
Example 2
Wrong (d) Cellulose is used for structure in a plant and starch is used for energy storage in plants.
Right (a) Both starch and cellulose are glucose polymers but their functions differs.
Example 3
Wrong (d) Cellulose is used for structure in a plant and starch is used for energy storage in plants. The cell wall of plant cells is composed of cellulose, which is strong and fibrous. Starch is composed of many connected glucose units. Starch can be stored by the plant in amyloplasts for future use.
Right (a) “Like starch, cellulose is a polymer of glucose, but the glycosidic linkages in these two polymers differ.” (p. 67) While starch has alpha bonds between the glucoses, cellulose has beta bonds.
Example 4
Wrong (d) Cellulose is used for structure in a plant and starch is used for energy storage in plants. The cell wall of plant cells is composed of cellulose, which is strong and fibrous. Starch is composed of many connected glucose units. Starch can be stored by the plant in amyloplasts for future use.
Right (a) Both starch and cellulose are made up of many glucose molecules linked together. Cellulose has beta glycosidic bonds between glucose and starch has alpha bonds. (include sketch)
Here are some examples of test corrections that are done the right way and the wrong way. See if you can tell why examples 1 and 2 are bad, and why examples 3 and 4 are good!
25. Which of the following is true both of starch and of cellulose?
a. They are both polymers of glucose.
b. They are geometric isomers of each other.
c. They can both be digested by humans.
d. They are both used for energy storage in plants.
e. They are both structural components of the plant cell wall.
Example 1
Wrong (d) Cellulose is not used for energy storage in plants
Right (a) Starch and cellulose are both polymers of glucose
Example 2
Wrong (d) Cellulose is used for structure in a plant and starch is used for energy storage in plants.
Right (a) Both starch and cellulose are glucose polymers but their functions differs.
Example 3
Wrong (d) Cellulose is used for structure in a plant and starch is used for energy storage in plants. The cell wall of plant cells is composed of cellulose, which is strong and fibrous. Starch is composed of many connected glucose units. Starch can be stored by the plant in amyloplasts for future use.
Right (a) “Like starch, cellulose is a polymer of glucose, but the glycosidic linkages in these two polymers differ.” (p. 67) While starch has alpha bonds between the glucoses, cellulose has beta bonds.
Example 4
Wrong (d) Cellulose is used for structure in a plant and starch is used for energy storage in plants. The cell wall of plant cells is composed of cellulose, which is strong and fibrous. Starch is composed of many connected glucose units. Starch can be stored by the plant in amyloplasts for future use.
Right (a) Both starch and cellulose are made up of many glucose molecules linked together. Cellulose has beta glycosidic bonds between glucose and starch has alpha bonds. (include sketch)