Unit 3 - Cellular Energetics

Thermodynamics

First Law of Thermodynamics energy cannot be created or destroyed the sum of energy in the universe is constant Second Law of Thermodynamics energy transfer leads to less and less organization universe tends towards entropy (disorder of the universe)

Reactions

Exergonic products have less energy than reactants energy is given off/released​​​​​​​

Endergonic products have more energy than reactants require an input of energy

Z5 Vjzco Td Gh1 Ld47y S7z Ilb Pa Z Rm8 Oxm Nvkcn1 Gf4 H Gp Cp Hf Br2 Cv Xi Sm Z Dt Wd Rdmws2r Nsj K5ia Eu Y Iuvr0f Tg Qee2z S3v A6 Ku Vqgl8rqz Gveegv G0 U K Tu Z Lls Dq7km Hy1 S Ui Yuvl If6 A Nn5 S3eq5509 Lmc=S800 (image/png)

P Wih Vx Gd A1 Rk6 L8 Zz Ztrxj Q Qkx Dff Dtogh Sk Vn0t I Na5p N8tmf In Sbk53d Is0689w R Ok0p R Pu3g K2xo Kb Ue86z Ykb6 Mery Ik Xvt C 0 Ld3vf Lk V Bo6b Z90qh Jq 15qkuah Yn Mnzs M9a Q Gpl3 J Bnl3 Zn Nrp Ja=S800 (image/png)

Gibbs Free Energy

ΔG=ΔH-TΔS T = temperature H = enthalpy (measure of energy in thermodynamic system) S = entropy changes in Gibbs free energy of a reaction determines whether the reaction is favorable (spontaneous, negative) or unfavorable (no spontaneous, positive) Spontaneous Reactions occurs without the net addition of energy ΔG<0=exergonic  ΔG>0=endergonic

Activation Energy even though exergonic reactions release energy, the reaction still needs energy to start with reactants must go through a transition state before turning into products activation energy = energy needed to achieve the  transition state bonds must be broken for new bonds to form

Enzymes

Enzyme =  biological catalysts that speed up reactions lowers activation energy and helps transition state form lowering of activation energy achieved by: orienting substrate correctly straining substrate bonds providing favorable emicroenvironment bonding to substrate doesn't change the energy of starting or ending point of reaction - only lowers activation energy Specificity - each enzymes only catalyzes one kind of reaction substrates are the reactants

Enzyme-Substrate Complex enzyme brings about transition state by helping the substrates get into position accomplished through active site once reaction has occurred, the enzyme is released from the complex and restored to original state induced fit the enzyme slightly changes shape to accommodate substrate cofactors = nonprotein helpers of enzymes that aid in induced fit and catalyzing reactions Enzyme can be denatured by pH (ideal is 7), temperature, and chemicals.

Enzymes

Competitive Inhibition a substance competes with a substrate for the active site of the enzyme if the substance out-competes, less reactions will occur if the substrate out-competes, reactions will occur as normal Allosteric Inhibitors/Non-Competitive Inhibition bonds to an allosteric site (not the active site) distorts shape of enzyme so that it cannot function and the substrate cannot bind/be catalyzed could also be used to stabilize the enzyme's active site (keeping site open)

Photosynthesis