Question

Radioisotopes used to detect newly synthesized protein is

• A. $C^{14}$
• B. $O^{18}$
• C. $N^{15}$
• D. $S^{35}$

Answer 1

Answer: (D)

Proteins are large-sized molecules having one or more polypeptides. Newly synthesized protein is detected by using radioisotope of sulphur $(S^{35})$ . Radioisotope of carbon $(C^{14})$ used to prove the $C{O}_2$ reduction in dark reaction of photosynthesis. Heavy isotope of oxygen $(O^{18})$ is used to determine that oxygen in photosynthesis released as a product of photolysis of water. Meselson and Stahl (1958) varified the semi-conservative nature of DNA-replication by using heavy isotope of nitrogen $(N^{15})$ .