ATP — Science definition

Defined in 2 courses:

Where it is taught

In use

ATP hydrolysis is favorable overall under typical cellular conditions and can be coupled to transport, movement, or synthesis.

Biochemical Reactions & Energy

ATP is an energy-transfer molecule used in many cell processes.

ATP & the Flow of Energy

Questions using atp

Problem 1

When ATP releases energy for the cell to use, it becomes
  1. DNA
  2. ADP + a phosphate group
  3. glucose
  4. a protein
Answer and explanation

ADP + a phosphate group

ATP hydrolysis forms ADP and phosphate; the overall reaction can release free energy under cellular conditions.

Problem 2

An active-transport pump uses 1 ATP to move 3 sodium ions out of a cell. How many ATP molecules are needed to pump 3,600 sodium ions?
Answer and explanation

1200 ATP

3,600 ions ÷ 3 ions per ATP = 1,200 ATP.

Problem 3

Explain how a decomposition reaction and a synthesis reaction can be linked together by ATP inside a cell.
Answer and explanation

Energy-releasing metabolism supports ATP production. ATP hydrolysis coupled to synthesis or transport can make the combined process favorable. No energy is created, and the full reactions, not bond breaking alone, determine the balance.

Problem 4

Explain why saying ATP provides energy because its bond is broken is incomplete. Explain the reasoning in your own words.
Answer and explanation

Energy availability comes from the whole reaction and coupling mechanism, not bond breaking by itself.

Bond breaking requires an input of energy.

The full reaction forms new interactions and products; its overall free-energy change can be favorable and coupled to work.

Response criteria

  • Use the stated conditions.
  • Show the evidence or calculation.
  • Explain the conclusion and any stated limitation.

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