Bioenergetics Flashcards
What is the definition of metabolism
Sum of anabolic/catabolic reactions in an organism
Why is metabolism important (3)
Obtain energy
Convert nutrients into those required by organisms
Needed for cellular work
Define intermediary metabolism
Combined activities of all the metabolic pathways that interconvert precursors/metabolites/products of low molecular weight
Catabolism
2 examples
Degradative phase of metabolism
ATP —> ADP
NADP —> NADPH
When many macromolecules forms one product
Converging
Anabolism
Biosynthesis phase of metabolism
ADP —> ATP
NADPH —> NADP+
One micro forms many macromolecules
Diverging
Exergonic reaction
Catabolism
Endergonic reaction
Anabolism
Compartmentalised
All work together but need other reactions for it to take place
Amphibolic reactions
Serves both anabolic + catabolic reactions
Krebs cycles
How is Krebs cycle amphibolic
Catabolism of carbs/FA into the cycle
Anabolic synthesis of precursors for amino acid synthesis
Where can anaplerotic reactions take place
What replenishes it
Krebs
Oxaloacetate
Name a negative feedback metabolism reaction
ADP activating phosphofructose kinase
As there’s deficiency in ATP
Name a positive feedback system metabolism
ATP inhibit phosphofructose kinase
Sufficient ATP is available
Define bioenergetics
Quantitative study of energy transductions in living organisms
In isolated systems, what happens with surroundings and exchange of energy
No exchange of energy between matter/surroundings
Closed system does what with energy
Exchanges energy not matter
No heat loss
Open system
All organisms
Exchanges matter/energy in a cell
2nd law of thermodynamics
Energy reaction will always lead to unusable energy
Energy able to do work is always less than the original amount of energy
Gibbs free energy definition
Amount of energy capable of doing work during a reaction
Negative delta G
Exergonic
Positive delta G
Endergonic
What is delta G related to
Directly related to reactant and product concentrations
Gibbs free energy reaction equation
Delta (H) - T delta (S)
What is H
Enthalpy
Heat content of the reacting system
Entropy
Quantitative expression for the randomness or disorder in a system
Gain in entropy
Products are less complex / more disordered
Sodium chloride in water
What amplifies entropy
Temperature
What can the Gibbs energy equation say if the value is NEGATIVE
Reaction can occur spontaneously
If the delta G is 0
System is equilibrium
Positive delta G
Energetically unfavourable
catabolic reaction always increase
Entropy
As exergonic reaction
Endergonic reactions lead to what in terms of entropy
Decrease in entropy
Products always start with (3)
More free energy
Less stable
Greater work capacity
Reactants end with (3)
Less free energy
More stable
Less work capacity
ATP hydrolysis is defined as what
What bond forms
Transfer of groups from ATP to substrate
Covalent bond
ATP —> ADP
What’s energy then used for
Negative G
Cellular work /chemical synthesis
ADP —> ATP
What’s formed in terms of stability
Positive G
More stable products than reactants
What 3 things stabilise products
Ionisation
Isomerization
Resonance
ATP provides energy by group transfer through how many reactions
2 step reaction
Bisphosphoglycerate forms what
Phosphoglyceric Acid
Via hydrolysis
Phosphoglyceric Acid forms what
3-phosphoglycerate
Ionisation
More stable products produced
Catabolic
Whats diverging
Give an example
Anabolism
Acetyl CoA —> cholesterol//phospholipids/tricyclgylcerides
What’s converging
Catabolism
Glycogen/surcrose/isoleucine —>Acetyl CoA
Units of Gibbs
Kj/mol -1
With redox potentials
Higher redox potential=
Lower redox potential =
Higher affinity (accepts electrons)
Lower affinity (donates electrons)
What does the standard redox potential state
Affinity of substance for electrons
If something donates electrons what agent is it
Reducing agent
If something accepts electrons what is it
Oxidising agent
What do endergonic reactions do to enthalpy and entropy
Decrease entropy
Increase enthalpy
What do exergonic reactions do to enthalpy and entropy
Increase entropy
Decrease enthalpy
