Every living organism, regardless of size or complexity, utilizes the same molecule, adenosine triphosphate (ATP), to power cellular processes.
ATP is the primary molecule used to transfer energy within cells.
It's an RNA nucleotide composed of:
A nitrogenous base: adenine
A 5-carbon sugar: ribose
A tail of three phosphate molecules
ATP serves as the universal energy currency, facilitating various biochemical processes.
Transport of substances
Muscle contraction
Synthesis of large molecules
ATP is essential for cellular processes requiring energy, including:
Active Transport:
Moving molecules against their concentration gradient necessitates active transport.
ATP binds to transport proteins, releasing a phosphate group, which transfers energy to the protein.
This energy enables the protein to move the molecule across the membrane.
Synthesis of Macromolecules (Anabolism):
The formation of bonds in macromolecules like proteins and DNA requires energy from ATP.
Enzymes catalyzing these reactions rely on ATP to function correctly.
Movement:
ATP fuels cell movement and the movement of components within the cell.
Cell movement involves the cytoskeleton, a network of protein filaments.
ATP provides the energy to bond fragments together.
The growth and contraction of these filaments lead to changes in cell structure and movement.
Example: A phagocyte engulfing a bacterium uses ATP to extend its membrane around the bacterium via cytoskeleton movement.
ATP carries chemical energy within a cell.
Hydrolysis: Breaking the bond between the second and third phosphate groups in ATP's tail releases energy in an exergonic reaction.
This process involves adding a water molecule (H2O$$H_2O$$).
ATP is converted into adenosine diphosphate (ADP).
Phosphorylation: The generation of ATP involves adding a phosphate group to ADP in an endergonic reaction.
A water molecule is removed during this process.
Energy is stored temporarily during ATP synthesis and released during ATP hydrolysis.
C1.2 Cell Respiration ATP
Every living organism, regardless of size or complexity, utilizes the same molecule, adenosine triphosphate (ATP), to power cellular processes.
ATP is essential for cellular processes requiring energy, including: