ATP is a co-substrate of the enzyme phosphofructokinase (PFK/PFK-1). In most species, ATP is also an inhibitor of PFK-1 at higher concentrations. Which statement below would provide a suitable explanation for this discrepancy?

A. There are two sites on PFK-1 that bind ATP. One is the active site; the other is the regulatory site where inhibition occurs.
B There must be another cofactor interacting with ATP at high concentrations to achieve inhibition of PFK-1.
C. ATP is unable to bind to the allosteric site on PFK at high concentrations.
D. ATP actually activates the reverse of the reaction preceding the PFK-1 step in the pathway. It likely has no direct effect on PFK-1.

answer:   option a) glucagon was secreted by his pancreas before he ate the cookies because blood glucose was low. insulin was secreted after he ate the cookies because his blood glucose was high.

explanation:

1. a host loses nutrients to a parasite

2. a parasite only benefits when the host is alive (cause if the host dies the parasite dies with it )

3. producers to consumers

4. the tapeworm is a parasite

5. they convert energy from the sun (photosynthesis)

6. sunflower-robin (i think im 80% sure)

7. producer

8. consumer

9. prey

10. fresh water snails ( cause the green algea is the producer and the snails are the primary consumers and the small fish consumer so is the big fish)