Final answer:
Neelaredoxin is continuously expressed in anaerobic prokaryotes, with its production level remaining constant even when exposed to oxygen or hydrogen peroxide. It does not follow the same expression pattern as some other stress-response proteins which might see increased expression under certain conditions.
Step-by-step explanation:
The student's question is about the expression of neelaredoxin, a protein with superoxide-scavenging activity commonly found in anaerobic prokaryotes. Based on the provided information, neelaredoxin is constitutively expressed, meaning it is produced continuously, regardless of the presence of oxygen or hydrogen peroxide. Therefore, its expression does not increase when exposed to O₂ or H₂O₂.
In relation to other proteins such as superoxide dismutase, which see an increased expression during stress or pathogen attack in plants, neelaredoxin operates differently by maintaining a constant level of expression. This constant synthesis, despite environmental conditions, can be contrasted with other proteins whose synthesis levels may vary in response to changes in cellular environment, including those influenced by oxidative stress or during a defense response.
Therefore, the correct answer from the provided multiple choice options regarding neelaredoxin synthesis is:
- Neelaredoxin is produced at all times; levels are constant even when exposed to O₂ or H₂O₂.