Cells need energy to carry out work, including reactions that require an input of energy. This lesson explains how ATP supplies energy for cellular work and introduces glycolysis, the first step in extracting energy from glucose.
Even reactions that release energy need a small input called activation energy to begin. Endergonic reactions need energy input because their products contain more free energy than their reactants. Cells use adenosine triphosphate (ATP) to supply energy for many energy-requiring reactions.
All flashcards
Why is ATP often called the cell's energy currency?
ATP stores energy in a form that cells can release when needed and uses that energy to power many cellular reactions and forms of work.
What is the structural difference between AMP, ADP, and ATP?
They contain adenine and ribose with different numbers of phosphate groups: AMP has one, ADP has two, and ATP has three.
What is ATP hydrolysis?
It is the breakdown of ATP by reaction with water, usually removing its terminal phosphate group and releasing energy.
Where does glycolysis occur, and what are its starting and ending molecules?
Glycolysis occurs in the cytoplasm. It begins with one six-carbon glucose molecule and ends with two three-carbon pyruvate molecules.
What happens in the two phases of glycolysis?
The first phase uses energy to prepare glucose for an even split. The second phase produces ATP and NADH as the resulting molecules are processed.
Quiz questions
Why do endergonic reactions require an input of energy?Answer: Their products contain more free energy than their reactants.
Which components make up adenosine monophosphate (AMP)?Answer: Adenine, ribose, and one phosphate group.
How can ATP help activate another molecule for cellular work?Answer: A phosphate group from ATP can bind to the molecule and help activate it.
What is the main role of the energy-investment phase of glycolysis?Answer: It uses energy to prepare glucose for an even split into two three-carbon molecules.
What happens if glycolysis is interrupted in a mature mammalian red blood cell?Answer: The cell eventually dies because glycolysis is its sole source of ATP.
Based on Concepts of Biology by Samantha Fowler, Rebecca Roush, James Wise (OpenStax), licensed CC BY 4.0. Adapted into a summary, flashcards and quizzes.