Data suggest that rubisco (ribulose-1,5-bisphosphate carboxylase)makes up 10% of the total protein found in spinach leaves.Research elucidating the structure of rubisco shows that it has four active sites.Why,with four active sites,might there be such a large concentration of rubisco in plant matter?
A)All heterotrophic organisms depend on plants,either directly or indirectly,for their food supply.
B)Rubisco is a very slow enzyme;what it lacks in speed,it makes up in quantity.
C)Rubisco catalyzes four of the six reactions found in the Calvin cycle.
D)Three of the four active sites bind carbon dioxide;only one binds ribulose-1,5-bisphosphate.

Question

Quizplus · Accepted Answer

Rubisco is a slow enzyme, so plants produce it in large quantities to compensate for its low catalytic rate, ensuring efficient carbon fixation.

Data Suggest That Rubisco (Ribulose-1,5-Bisphosphate Carboxylase)makes Up 10% of the Total