Structure and Function of ATP (Q1) Flashcards
Components of adenosine triphosphate (ATP)
- Chain of three phosphate groups
- Pentose sugar ribose/ 5-carbon sugar
- Nitrogenous base (adenine)
Combining ribose sugar and adenine results in a nucleoside called _______.
Adenosine
Functions of ATP
- Mediates energy coupling
- Acts as immediate energy source for cellular work
- Used in making RNA
How does energy coupling help in cell work?
Energy coupling allows cells to transfer energy from one reaction to another wherein cells use an exergonic process to drive an endergonic reaction.
Kinds of work of a cell
- Chemical work
- Transport work
- Mechanical work
Example of chemical work
Synthesis of polymers from monomers (Endergonic reaction)
Example of transport work
Pumping of substances across membranes against spontaneous movement
Example of mechanical work
Beating of cilia, muscle contraction
Why can ATP also produce RNA?
RNA is composed of ribose sugar attached to nitrogenous bases and phosphate groups.
Bond connecting ribose sugar and phosphate group
Phosphoester bonds
Bond connecting phosphate groups to each other
Phosphoanhydride bonds
Process that uses water to break down the bond between phosphate groups
Hydrolysis
Where is the energy stored in ATP?
Between the bonds connecting the phosphate groups together
Why are phosphoanhydride bonds unstable?
Due to the electrostatic repulsion between the negative charges in the oxygen atoms of the three phosphate groups
What kind of energy is stored in the bonds between phosphate groups?
Potential chemical energy
How is the stored potential energy between the phosphate group bonds released?
By releasing one phosphate group
Is ATP hydrolysis exergonic or endergonic?
Exergonic
How much energy does hydrolysis release?
-7.3 kcal/mol or -30.5 kJ/mol
What enzyme catalyzes the hydrolysis of the bond between the second and third phosphate group in ATP?
ATPase
Products of ATP hydrolysis
- Adenosine diphosphate (ADP)
- Inorganic phosphate (HOPO3 ^-2)
- Energy
Write the chemical equation for ATP hydrolysis.
ATP + H20 –> ADP + Pi + Energy
Where does the release of energy come from?
From the chemical change of the system state of lower free energy
ATP hydrolysis leads to changes in protein shape and its binding ability with another molecule. True or False?
True
Process of converting ADP to ATP
Phosphorylation
Process of converting ATP to ADP
Dephosphorylation
Is the hydrolysis of ATP to ADP reversible?
Yes
Is the hydrolysis of ATP spontaneous or non-spontaneous?
It is spontaneous because there is a release of free energy.
