Cellular Respiration Flashcards
Energy
the ability to do work
First Law of Thermodynamics
- energy can not be created or destroyed, only changed into different forms
- total amount of energy in universe remains constant
- during conversion, some energy is lost as heat
Second Law of Thermodynamics
- entropy (disorder) is continuosly increasing as it is spontaneous
- energy transformations spontaneously to convert from more order to less order
- diffusion increases entropy as molecules becomes more spread out
_________ happens spontaneously
Disorder happens spontaneously
________ requires energy
Organization requires energy
Free energy
energy of system available to do work
∆G = ∆H -TS
G: gibbs free energy
H: total energy of system, enthalpy
T: absolute temperature
S: degree of disorder/entropy
+ ∆G
- products have more free energy than reactant
- H is higher or S is lower
- NOT SPONTANEOUS
- requires energy input
- Endergonic/Anabolic
-∆G
- products have less free energy than reactant
- H is lower or S is higher
- SPONTANEOUS
- Exergonic/Catabolic
Catabolism + Anabolism =
Metabolism
Metabolism
- sum of all chemical reactions in a living system
Catabolism
- all destructive reactions that release energy
- exergonic reactions
- digestion and respiration
Anabolism
- all constructive reactions that require input of free energy and decrease entropy of body
- endergonic reaction
- protein synthesis and photosynthesis
Coupled Anabolic Reaction
couple exergonic and endergonic reaction where net energy of reaction is negative
Coupled Catabolic Reaction
couple exergonic and endergonic reaction where net energy of reaction is positive
Since _____ reactions that build the complex of living systems are _____, a continuos intake of energy that can be _____ in _______ reactions to do work is needed
Since anabolic/contructive reactions that build the complex of living systems are endergonic, a continuos intake of energy that can be released in exergonic/catabolic reactions to do work is needed
Chemosynthesis
inorganic exergonic reactions coupled with endergonic synthesis reaction to produce food molecules
Where does the energy come from?
- living things can only do work by harnessing and converting energy sources
- GLUCOSE is universal source of energetic electrons because the C-H and C-C are energetic enough to yield energy if electrons are transferred to more electronegative source
Cellular Respiration
- aerobic respiration, exergonic with series of coupled reactions
- breakdown of glucose to synthesize ATP
- rearranging molecules in small steps using enzymes, until bonds become unstable and release phosphate to form ATP, or electrons stored for later reaction
Oxidation
losing an electron to oxygen or more electronegative molecule, exergonic reaction
Reduction
reducing charge, gaining an electron, endergonic reaction
Redox Reaction
one substance gaining electron and one loses electron
LEO says GER
loss of electron=oxidation
gain of electron=reduction
Activation Energy
energy required to initiate a CR
3 steps of Cellular Respiration
- Glycolysis
- Krebs Cycle
- Electron Transport Chain
Where does glycolysis occur?
In the cytoplasm of the cell
Glucose Priming
1st step of Glycolysis
- 6 Carbon Glucose with rearranged into Fructose iwth 2 phosphates from ATP (energy investment)
- phosphate makes 6-carbon molecule unstable and lower activation energy
- rearranged into Fructose 1 6-Biphosphate
- has inhibitor of phosphofruktokinase
Cleavage/Breakdown of Glucose
2nd Step of Glycolysis
- 6 carbon molecule with 2 phosphate splits as 2 isomers of 3-Carbon sugar phosphate aldehydes
Energy Yielding (Glycolysis)
3rd step of Glycolysis
- inorganic phosphate joins and catylized by enzyme, NAD+ gains 2 electrons in redox reaction
- one of the 2 phosphates binds to ADP to form ATP and leaves behind 3-Carbon sugar + 1 phosphate
- A few chemical rearrangements
- Substrate level phosphorolation of PEP into 3-Carbon Pyruvate resulting in another ATP
Glycolysis
- product is 2 pyruvate
- a net 2ATP and 2NADH+ H+ are produced after input of 2ATP
Substrate Level Phosphorolation
metabollic process that results in formation of ATP from a direct transfer of phosphate group
Krebs Cycle
- takes place in the mitochondrion
- a net of 8NADH+H+ , 2FADH2 and 2ATP formed
(6 NADH+H+ formed from oxidate decarboxylation, 2 formed by redox reaction)
- 6CO2 released