If a strain of Neurospora is unable to grow on minimal medium but can grow when substance A is added to minimal medium, then
A) the strain is wild type.
B) the strain lacks the enzyme or enzymes needed to break down substance A.
C) the strain lacks the enzyme or enzymes needed to synthesize substance A.
D) substance A must be an enzyme.
E) substance A must be a mutagen.

Question

Quizplus · Accepted Answer

If the strain is unable to grow on minimal medium but can grow when substance A is added, it means that substance A is a necessary nutrient for the strain. Therefore, the strain lacks the enzyme or enzymes needed to synthesize substance A, which is why it cannot grow on minimal medium alone.

If a Strain of Neurospora Is Unable to Grow on Minimal