ATP is the cell’s primary energy currency. This lesson explains what ATP is made of, how its hydrolysis releases energy, and why the amount of energy released depends on conditions.
Adenosine triphosphate (ATP) is a relatively small molecule that stores potential energy in its chemical structure and supplies energy for many cellular reactions. Cells use ATP to power processes that require energy, including endergonic reactions, whose products have more free energy than their reactants.
All flashcards
What is ATP, and what role does it play in cells?
Adenosine triphosphate, a major energy currency that helps power cellular work.
What is adenosine made of?
Adenine and the five-carbon sugar ribose.
Why does ATP hydrolysis release free energy?
Its products, ADP and inorganic phosphate, have lower free energy than ATP and water.
What is energy coupling in cellular processes?
Linking an energy-releasing reaction to help drive an energy-requiring process.
How does ATP hydrolysis energy differ between standard and cellular conditions?
It is about −7.3 kcal/mol under standard conditions and often about −14 kcal/mol in cells.
Quiz questions
Which components make up an ATP molecule?Answer: Adenine, ribose, and three phosphate groups.
Why does ATP hydrolysis release free energy?Answer: ADP and inorganic phosphate have lower free energy than ATP and water.
During one sodium-potassium pump cycle, which ions move across the membrane?Answer: Three sodium ions move out, and two potassium ions move in.
What can happen when ATP transfers a phosphate group to a target molecule?Answer: The target can gain free energy or undergo a conformational change.
How does ATP help prepare glucose for early glycolysis?Answer: It transfers a phosphate to glucose, helping prepare it for conversion into phosphorylated fructose.
Based on Biology 2e by Mary Ann Clark, Matthew Douglas, Jung Choi (OpenStax), licensed CC BY 4.0. Adapted into a summary, flashcards and quizzes.