With no explanation, label text_A→text_B with either "DON'T KNOW", "NO" or "YES".
text_A: These adenylyl cyclases are the most familiar based on extensive study due to their important roles in human health. They are also found in some bacteria, notably "Mycobacterium tuberculosis" where they appear to have a key role in pathogenesis. Most AC-III's are integral membrane proteins involved in transducing extracellular signals into intracellular responses. A Nobel Prize was awarded to Earl Sutherland in 1971 for discovering the key role of AC-III in human liver, where adrenaline indirectly stimulates AC to mobilize stored energy in the "fight or flight" response. The effect of adrenaline is via a G protein signaling cascade, which transmits chemical signals from outside the cell across the membrane to the inside of the cell (cytoplasm). The outside signal (in this case, adrenaline) binds to a receptor, which transmits a signal to the G protein, which transmits a signal to adenylyl cyclase, which transmits a signal by converting adenosine triphosphate to cyclic adenosine monophosphate (cAMP). cAMP is known as a second messenger.
text_B: If someone were making an analogy between airplane flights and the relationship between adrenaline and AC, would they describe it as a direct flight?
NO.