Living organisms require a continual input of free energy for: (3)
- the performance of mechanical work in muscle contraction and cellular movements
- the active transport of molecules and ions
- the synthesis of macromolecules from simple precursors
Metabolism
-definition
Complex regulated system of energy- producing and energy utilizing chemical reactions, cell depend on
Metabolism
-a linked series of chemical reactions that: (3)
- begins with a particular biomolecule
- converts it into some other required biomolecule
- does not generate wasteful or harmful side products
Metabolic pathways
- catabolic
- anabolic
- convert energy from fuels into biologically useful forms, such as ATP.
- the synthesis of complex molecules in living organisms from simpler ones
Bioenergetics (3)
- the study of energy changes accompanying chemical reactions
- it describes the transfer and utilization of energy in biologic systems
- it concerns only the initial and final energy states of reaction components. It predicts if it is possible
Fundamental Law of thermodynamics (2)
The principal of the conservation of energy: total amount of energy in the universe remains constant
The universe always tends towards increasing disorder: in all processes, the entropy of the universe increases
Gibbs free energy - (G)
-2
- the amount of energy capable of doing work during a reaction at constant temperature and pressure
- free- energy change: is a measure of the chemical energy avaiable from a reaction
Enthalpy - (H)
-3
- the heat content of the reacting system
- reflects the number and kinds of chemical bonds in the reactants and products
- Exothermic (reaction releases heat), endothermic (reaction takes up heat)
Entropy - (S)
-expression for the randomness or disorder in a system
If delta G is …. the reaction will be spontaneous or not
- negative
- positive
- delta G negative: spontaneous
- delta G positive: non- spontaneous
Exergonic reactions (4)
- when a reaction proceeds with the release of free energy.
- delta G is negative
- thermodynamically favored reactions
- mainly catabolic pathways
Endergonic reactions (5)
- the system gains free energy
- delta G is positive
- thermodynamically unfavored reactions
- mainly anabolic pathways
- not spontaneous
ΔGo (2)
- equal to the free energy change under standard conditions
- when reactants and products are at 1 mol/L concentrations and pH 0
ΔG’ & coupling reactions
- definition
- example
- when an energetically favorable reaction is directly linked with an energetically unfavorable reaction.
- ex: hydrolysis of ATP + endergonic reaction
Chemical structure of ATP
- adenine
- ribose
- 3 phosphate groups
The standard free energy of hydrolysis of ATP is:
ΔGo is -7.3 kcal/ mol
Why is ATP called a high- energy phosphate compound?
Because it has a large negative ΔGo
High energy bonds
-definition
Any bond that can be hydrolyzed with the release of approximately as much, or more, energy than ATP
Name
-2 high energy and 2 low energy compounds
- high: creatine, phosphoenolpyruvate, 1,3-bisphosphoglycerate
- low: glucose- 6 and glycerol- 3
How is ADP converted back to ATP?
By the process of oxidative phosphorylation, using energy supplied by fuel oxidation or substrate level phosphorylation
ATP can be formed from…
Two ADP by adenylate kinase transferring a phosphate from one ADP to another ADP to form ATP and AMP
Extraction of energy from fuels
-steps (4)
- fats, polysaccharides, proteins
- Acetyl CoA
- Citric acid cycle
- Oxidative phosphorylation
Metabolic pathways
Fuels are degraded and large molecules are constructed step by step in a series of linked reactions
ATP links two types of pathways, name them
energy-releasing pathways with energy- requiring pathways
