Wild-type bacteria can synthesize substance D, but various mutant strains cannot.We know that substance D is synthesized from substance X in a pathway that involves three intermediate substances (A, B, and C), but we do not know the order of the steps in the pathway.The table shows four different mutant strains that have been tested for their ability to grow on the various substances.A "+" means that the strain can grow on that substance; a "-" means that the strain cannot grow on that substance. Based on these data, what is the most likely order of the pathway? (A, B, C, D means that substance A is converted to substance B, which is converted to substance C, which is converted to substance D.)
A) A, B, C, D
B) A, C, B, D
C) B, A, C, D
D) C, B, A, D
E) C, A, B, D

Question

Wild-type bacteria can synthesize substance D, but various mutant strains cannot.We know that substance D is synthesized from substance X in a pathway that involves three intermediate substances (A, B, and C), but we do not know the order of the steps in the pathway.The table shows four different mutant strains that have been tested for their ability to grow on the various substances.A "+" means that the strain can grow on that substance; a "-" means that the strain cannot grow on that substance.  Based on these data, what is the most likely order of the pathway? (A, B, C, D means that substance A is converted to substance B, which is converted to substance C, which is converted to substance D.)
A) A, B, C, D 
B) A, C, B, D 
C) B, A, C, D 
D) C, B, A, D 
E) C, A, B, D

Quizplus · Accepted Answer

The Answer of Wild-type bacteria can synthesize substance D, but various mutant strains cannot.We know that substance D is synthesized from substance X in a pathway that involves three intermediate substances (A, B, and C), but we do not know the order of the steps in the pathway.The table shows four different mutant strains that have been tested for their ability to grow on the various substances.A "+" means that the strain can grow on that substance; a "-" means that the strain cannot grow on that substance.  Based on these data, what is the most likely order of the pathway? (A, B, C, D means that substance A is converted to substance B, which is converted to substance C, which is converted to substance D.)
A) A, B, C, D 
B) A, C, B, D 
C) B, A, C, D 
D) C, B, A, D 
E) C, A, B, D

Wild-Type Bacteria Can Synthesize Substance D, but Various Mutant Strains