Radioactive Isotopes of Various Elements Can Be Used to Label

question 28

Essay

Radioactive isotopes of various elements can be used to label molecules for use in studies of metabolic pathways. For example, 14C is a radioactive isotope of carbon and naturally occurs at much lower rates than non- radioactive 12C (i.e. most molecules contain 12C carbon atoms). A cell can be fed a nutrient molecule labeled with the radioactive isotope and scientists can detect where the radioactive isotope ends up. For each of the following scenarios, trace the radioactive isotope to where it ultimately would end up after moving through the cellular respiration, fermentation, or biosynthetic pathways. Only consider these metabolic pathways; do not consider any other cellular processes.
A. E. coli is fed 14C- labeled glucose and grown under aerobic conditions.
B. E. coli is fed 14C- labeled glucose and grown under anaerobic conditions (fermentation).
C. E. coli is fed 14C- labeled fatty acids and grown under aerobic conditions.
D. E. coli is fed 14C- labeled acetyl CoA and grown under conditions that promote biosynthetic pathways.

---

Definitions:

Influence

The capacity to have an effect on the character, development, or behavior of someone or something, or the effect itself.

Introspection

The examination or observance of one's own emotional and mental processes, allowing for self-awareness and understanding.

Objectivity

The quality of being unbiased, detached, and free of any personal or subjective influences.

Individual Measurements

Refers to the unique data gathered from single entities or participants in a study, highlighting variations among them.