2.3 ATP With Test Questions And
Answers
What is ATP? - Answer - A single molecule of adenosine triphosphate (ATP) is a nucleotide derivative and
is formed from a molecule of ribose, a molecule of adenine and three phosphate groups.
How does ATP store energy? - Answer - When energy is needed by a cell, ATP is broken down into ATP,
and Pi in a hydrolysis reaction catalysed by ATP hydrolase. A phosphate bond is broken and energy is
released. Bonds between phosphate groups are unstable and have low activation energy so when they
are broken, energy is released
What is meant that ATP hydrolysis can be coupled to other energy requiring reactions in the cell? -
Answer - This means energy can be used directly to make the coupled reaction happen, rather than
being lost as heat.
What can the inorganic phosphate be used for? - Answer - The inorganic phosphate released during the
hydrolysis of ATP can be used to phosphorylate other compounds, often making them more reactive.
This is known as phosphorylation.
How does ATP return? - Answer - ATP can be re-synthesisised in a condensation reaction between ADP
and Pi. This happens during both respiration and photosynthesis and is catalysed by the enzyme ATP
synthase.
Synthesis of ATP occurs in 3 ways, Name them. - Answer - - in chlorophyll containing plant cells during
photosynthesis ( phosphorylation)
- Plants and animals in respiration - oxidative phosphorylation
- Plant and animal cells, when phosphate groups are transferred from donor molecules to ADP
(substrate level phosphorylation) .
Answers
What is ATP? - Answer - A single molecule of adenosine triphosphate (ATP) is a nucleotide derivative and
is formed from a molecule of ribose, a molecule of adenine and three phosphate groups.
How does ATP store energy? - Answer - When energy is needed by a cell, ATP is broken down into ATP,
and Pi in a hydrolysis reaction catalysed by ATP hydrolase. A phosphate bond is broken and energy is
released. Bonds between phosphate groups are unstable and have low activation energy so when they
are broken, energy is released
What is meant that ATP hydrolysis can be coupled to other energy requiring reactions in the cell? -
Answer - This means energy can be used directly to make the coupled reaction happen, rather than
being lost as heat.
What can the inorganic phosphate be used for? - Answer - The inorganic phosphate released during the
hydrolysis of ATP can be used to phosphorylate other compounds, often making them more reactive.
This is known as phosphorylation.
How does ATP return? - Answer - ATP can be re-synthesisised in a condensation reaction between ADP
and Pi. This happens during both respiration and photosynthesis and is catalysed by the enzyme ATP
synthase.
Synthesis of ATP occurs in 3 ways, Name them. - Answer - - in chlorophyll containing plant cells during
photosynthesis ( phosphorylation)
- Plants and animals in respiration - oxidative phosphorylation
- Plant and animal cells, when phosphate groups are transferred from donor molecules to ADP
(substrate level phosphorylation) .
