intro to metabolism and bioenergetics Flashcards
bioenergetics
scientific term uses to describe the transfer and utilization of energy (energy flow) in biological systems
Energy
The ability to do work
in biological systems energy is neither created nor lost but only converted from one form to another
free energy change deltaG
provide a measure of the energetic feasibility of a chemical reaction and therefore allow prediction of whether a reaction can take place
metabolism
all of the chemical reactions that take place inside the organism (cell)
Enthalpy
deltaH
a measure of the change in heat content of the reactants and products
entropy
delta S
a measure of the change in randomness or disorder of reactants and products
absoulte temperature
T
in Kelvin
Exergonic
can proceed spontaneously
delta is negative
energy is released
Endergonic
Cannot proceed spontaneously
deltaG positive
energy must be added
deltaG=0
the reactant and product reach equilibrium
what does deltaG depend on?
concentration of A and B
deltaG=standard free energy + RT ln[B]/[A]
standard free energy
free energy change under standard conditions
pathways
reactions in cells are generally organized into multistep sequences
Example-glycolysis
the product of one reaction…
serves as the substrate of a subsequent reaction
metabolism
different pathways can also intersect, forming integrated and purposeful network of chemical reactions
what does the actual rate of the pathway depend on?
activity of the enzymes that catalyze each step
catabolic reactions
exergonic
releases the energy stored in the complex molecules during their break down to simple end products
anabolic reactions
endergonic
consumes energy to synthesize complex molecules from simple precursors
Human metabolism serves 2 purposes
- the capture of energy in the form of ATP or reduced compounds from the degradation of energy rich fuel molecules
- allows dietary molecules or nutrients stored in cells to be converted into building blocks to be used for synthesis of complex molecules
3 major steps of catabolic pathways
- Hydrolysis of complex molecules
2conversion of building blocks to simple intermediates - oxidation of acetyl CoA
oxidation of acetyl CoA
the TCA cycle is the final common pathway in the oxidation of fuel molecules to produce NADH and FADH2
anabolic pathways
require energy (ATP, NADH, NADPH) divergent process
regulation of metabolism
coordinate the function of the body as a whole
