Role of ATP I Flashcards
1
Q
Metabolism
A
Integrated set of enzymatic reactions comprising both of anabolic and catabolic reactions
2
Q
Anabolism
A
Synthesis of complex molecules from simpler ones (necessary energy usually derived from ATP)
3
Q
Catabolism
A
Breakdown of energy-rich molecules to simpler ones (CO2, H2O and NH3)
4
Q
Metabolism summary [2]
A
Anabolism: Synthetic reactions - the pathways end in ‘genesis’
Catabolism: Breakdown reactions - the pathways end in ‘lysis’
5
Q
Energy required for [4]
A
- Motion (muscle contraction)
- Transport (of ions/molecules across membranes)
- Biosynthesis of essential metabolites
- Thermoregulation
6
Q
Free energy
A
Cells are isothermal systems Heat flow cannot be used as a source of energy (heat can only do work when it passes to an area or an object at a lower temperature) Free energy (energy available to perform work) is acquired from nutrient molecules
7
Q
Gibbs free energy [3]
A
- Enthalpy (H): Heat content of the reacting system
- Entropy (S): Randomness or disorder in a system
- Gibbs free energy (G): Energy capable of doing work at constant temperature and pressure
8
Q
For the reaction A-> B
If the concentration of B > A at equlibrium
A
- Spontaneous or exergonic reaction
- Free energy is defined as negative DG < 0
- Energy is liberated by the reaction
9
Q
For the reaction A-> B
If the concentration of A > B at equilibrium
A
- Unfavourable or endergonic reaction
- Free energy is defined as positive DG> 0
- Energy input is required to start the reaction
10
Q
Adenosine Triphosphate
A
- ATP provides most of the free energy required
- ATP is the energy currency of the cell
- Achieved by phosphate group transfer
- Gibbs free energy: The energy derived from the oxidation of dietary fuels
- Energy is conserved as ATP and is transduced into useful work
11
Q
ATP/ADP Mg2+ complexes [2]
A
- ATP in the cytosol is present as a complex with Mg2+
- Mg2+ interacts with the oxygens of triphosphate chain making it susceptible to cleavage in the phosphoryl transfer reaction
12
Q
Substrate level phosphorylation (SLP) [2]
A
- Formation of ATP by phosphoryl group transfer from a substrate to ADP
- SLPs require soluble enzymes and chemical intermediates
13
Q
Enzymes [3]
A
- Biological catalysts that accelerates the rate of chemical reactions
- Creates a new pathway for reactions, one with a lower activation reaction
- Does not influence the Delta G of the reaction
14
Q
Coenzymes [6]
A
- Non-protein cofactors - eg metal cation
- Most coenzymes derived from vitamins
- Participate in the enzymatic reaction
- Have a loose association with their enzyme
- Diffuse from one enzyme to the next carry e-
- Regenerated to maintain cellular concentration
15
Q
Prosthetic groups [3]
A
- Non-protein cofactor that is covalently bound to the enzyme
- Not released as part of the reaction
- Acts as a temporary store for e- or intermediate
