本题目来源于试卷: Interaction & Interdependence C.3 Photosynthesis，类别为 IB生物学
[单选题]
What were the results ob6c)afpm9 4z hotained from the lollipop experc81qb n*:vmrkf0fj ;niment that enabled Calvin to determine the order of the light-independent reactions *b;m8nfvkr1q: n0f j cof photosynthesis?
A. Algae Chlorella were killed after being added to hot methanol.
B. A high percentage of radioactivity was found in glycerate-3-phosphate in the first sample.
C. A large amount of triose phosphate and other sugar phosphates were found in the first sample.
D. $12CO_2$was replaced by $14CO_2$ , a radioactive isotope of carbon which was supplied to the algae Chlorella.
参考答案: B
本题详细解析:
B The lollipop experiment by Melvin Calvin and his team aimed to determine the pathway of the light-independent reactions. Calvin and his team took algae Chlorella samples at different time intervals to identify which carbon compounds in the algae contained the radioactive isotope of carbon,14C.Hence, the12$CO_2$supplied to the algae at the start of the experiment was then replaced with14C instead which was added by the researchers. This is not part of the results, but one of the experimental steps (Choice D). Additionally, the algae were added to hot methanol which killed the algae enabling the researchers to analyse the results at that time interval. This is also not part of the results, but one of the experimental steps (Choice A). The results showed a high percentage of radioactive carbon in glycerate-3-phosphate in the first sample. This shows that the glycerate-3-phosphate is one of the first products of the light-independent reaction. An increase in the percentage of radioactivity in triose phosphate and other sugar phosphates in the later samples and not the first samples shows that these are intermediate and final products of the light-independent reaction (Choice C).
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