T2 L2: Role of ATP in living cells 1 Flashcards
(34 cards)
What does anabolism mean?
Synthesis of complex molecules from simpler ones (‘genesis’ reactions)
What does Catabolism mean?
Breakdown of energy-rich molecules to simpler ones (‘Lysis’ reactions)
What does isothermal mean?
Maintaining a constant temperature
When can the flow of heat be used a source of energy?
When it passes to an object or area of lower energy
What is meant by ‘free’ energy?
Energy available to do work
What is the equation for Gibbs free energy?
ΔG= ΔH - TΔS (G= Gibbs free energy, H= enthalpy, S= Entropy, T= temperature)
What is enthalpy?
Energy that can be found in chemical bonds
What is entropy?
Disorder of molecules
What is meant by a Gibbs free energy (ΔG) of a reaction?
The maximum energy that can be obtained from a reaction at constant temperature and pressure
What happens in a chemical reaction if the [products] is greater than the [reactants]?
Spontaneous/ exergonic (exothermal) reaction (ΔG < 0)
What happens in a chemical reaction if the [reactants] is greater than the [products]?
Unfavourable/ endergonic (Endothermal) reaction (ΔG > 0)
When can chemical reactions be coupled?
When they have common intermediates
What is ATP associated with in the cytosol and why?
To a Mg2+ complex because Mg2+ interacts with O2 of the triphosphate chain making it more susceptible to cleavage by phosphorylation. Without Mg2+, cleavage doesn’t happen efficiently
What is SLP?
Substrate level phosphorylation is the formation of ATP by phosphate group transfer from a substrate of ADP
What do oxidoreductases do?
Transfer e-
What do transferases do?
Transfer functional groups
What do hydrolases do?
Add H2O
What do Lyases (Synthases) do?
Cleave or form bonds
What do Isomerases do?
Transfer groups within a molecule
What do Ligases (Synthetases) do?
Form bonds coupled to ATP hydrolases
What are co-factors?
Non-protein molecules necessary for enzyme activity mostly derived from vitamins. They are loosely associated with their enzyme and are able to diffuse between enzymes carrying e-
What are prosthetic groups?
Non-protein co-factors that are covalently bound to the enzyme. They’re not released as part of the reaction and act as temporary stores for e- or intermediates
What are 2 differences between co-enzymes and prosthetic groups?
Prosthetic groups are covalently bonded, co-factors are loosely associated. Co-factors can diffuse between enzymes carrying e-, prosthetic groups store e-
What is the co-enzyme of vitamin B2 (Riboflavin)?
FAD or FMN (prosthetic group)
