Energy Use In cells. Matter – anything that has mass and takes ups space Energy - capacity to do work or bring about change Matter is a form of energy [ E=mc 2 ] > 4 billion kg of matter per second are converted into energy in the sun
Energy flows as heat energy from an object with a higher temperature to an object with lower temperature
Second law – When energy is converted from one form to another, some usable energy (energy available to do work) is converted to heat. Heat is the KE of randomly moving particles. This heat – the random motion of particles- cannot do work.
Organisms are open systems. They exchange energy and materials with the environment. Organization is maintained through a constant input of energy.
In order to talk about how much usable energy is available to a cell, we talk about
Enthalpy (H) – total PE of a system,
Entropy (S) – disorder and
Free Energy (G) – energy available to do work in biochemical reactions
G = H – T(S)
As entropy of a system increases, the amount of free energy decreases.Metabolism
When we measure the temperature difference of a process, we are measuring the enthalpy (PE) change of the system.
Exergonic reactions release energy. This means that the products have less free energy than was present in the reactants. The free energy of the system (energy available to do work) decreases and ∆G is considered to be negative. (ΔG = - )
- ∆G (exergonic) means that the reaction occurs without input of additional energy