Question

Using differential centrifugation, you are trying to isolate from a mixture of cellular organelles. After a few centrifugation steps, you think you may have a relatively pure suspension. How might you determine that your suspension does, indeed, have peroxisomes?

a. Do an assay for the enzyme catalase.
b. Assay your suspension for H2O2.
c. Look in the microscope for an organelle with a double membrane.
d. Do an assay for the enzyme succinate dehydrogenase.
e. Assay your suspension for nucleic acid.

Answer 1

To verify the presence of peroxisomes in a suspension, a catalase enzyme assay should be conducted. When hydrogen peroxide is added, the catalase present in peroxisomes will produce bubbling, confirming their presence.

Step-by-step explanation:

To determine if a suspension indeed contains peroxisomes, an assay for the enzyme catalase should be performed. Peroxisomes are single-membrane organelles that are notably for containing catalase, which converts hydrogen peroxide (H₂O₂) to water and oxygen. By adding H₂O₂ to the suspension and observing bubbling due to the release of oxygen, the presence of catalase can be confirmed, thereby indicating the presence of peroxisomes. This test is based on the unique function of peroxisomes in breaking down molecules such as fatty acids, and their role in lipid biosynthesis.

Other options such as assaying the suspension for H₂O₂, examining for a double membrane, performing assays for enzymes like succinate dehydrogenase, or testing for nucleic acid are either inappropriate or less specific when trying to confirm the presence of peroxisomes.