Please enable JavaScript.
Coggle requires JavaScript to display documents.
Metabolism: Set of Chemical Reactions that Sustain Life (Cellular…
Metabolism: Set of Chemical Reactions that Sustain Life
Organisms classification
photoautotrophs: cyanobacteria
Photoheterotrophs: heliobacteria, most green non-sulfur bacteria
Chemoautotrophs: sulfur-oxidizing bacteria, hydrogen bacteria
chemoheterotrophs: most bacteria and animals
Energy
Kinetic: any kind of movement
Potential: stored energy
Chemical energy = potential energy in chemical bonds
covalent bonds = stable configuration = lower potential energy
strong covalent bonds (lower potential energy and lower chemical energy) --> CO2 and H2O
Weaker covalent bonds (C-C): require energy to remain intact --> higher potential energy and lots of chemical energy
Electrons farther away from nucleus
ATP: packages unused energy; go-between fuel molecules
Large amount of potential energy (negative charges phosphate groups pushed together)
Readily accessible
DEF: Releasing potential energy = changing object or position in surroundings
Energy Flow in Biological Systems
First Law of Thermodynamics: Energy = conserved
Second Law of Thermodynamics: Energy transformations result in increased entropy
Energy available to do work decreases
Transformations never 100% efficient (heat)
Energy not available to do work transferred to disorder (ENTROPY)
Most entropy increase occurs through transformation of various forms of energy into thermal energy
Local decrease in entropy associated with increase in entropy of surroundings
ie: catabolic rxns: building macromolecules = decreasing entropy, heat released = increasing entropy of surroundings --> net increase of entropy
Chemical Rxns:
Rxn either requires or releases energy
Gibbs Free Energy (G): amount of energy available to do work
Enthalpy (H): total amount of energy (available energy)
H = G + TS
Energy available to do work (G) + energy lost to entropy (TS)
Catabolic rxns: products less chemical energy (lower enthalpy) in bonds than reactants: products more disordered (+S)
hydrolysis of ATP = exergonic rxn
ADP more stable
Free energy change = -7.3 kcal per mole
Release of free energy during ATP hydrolysis comes from breaking weaker bonds in reactants and forming more stable bonds in products
Non-spontaneous reactions --> Energetic coupling; two reactions occur together
Intermediate change in G allows ATP-ADP system to be core of catabolic and anabolic reactions
Cellular Respiration
#
Catabolic rxns convert energy in fuel molecules into ATP
Exergonic rxn, many intermediate steps within rxn (not all released as heat, otherwise, would just be heat)
ATP generation
Substrate-level phosphorylation
Hydrolysis of organic molecule
addition of phosphate group to ADP
12% ATP generation in respiration
Oxidative phosphorylation
Chemical energy transferred to electron carriers
Electron transport chain transfer electrons along series of proteins to final electron acceptor (in process, harness energy to produce ATP)
e movement + ATP synthesis
e carrier (FADH2 and NADH)
gain or loss of electrons accompanied by gain or loss of protons
Reduced molecules = increase in C-H bonds
Glycolysis: Partial oxidation
10 chemical rxns
Glucose + 2Pi + 2 molecules ATP --> glucose- 6phosphate/other phosphorylated versions of glucose (2 Pi groups causes molecule to be very inactive)
6 carbon molecule --> two 3 carbon molecule
Payoff phase: 2 ATP and 1 NADH produced
Net 2 ATP and 2 NADH
Pyruvate --> acetyl-CoA
Pyruvate transferred to matrix
Pyruvate oxidized (Carboxyl --> CO2)
NAD+ --> NADH
Conenzyme A added to pyruvate
Citric Acid Cycle
8 reactions
2C acetyl group transferred to 4C oxaloacetate --> 6C citric acid (molecule oxidized)
2 C eliminated in form of CO2
Electron Transport Chain: complete oxidation of glucose, putting generated electron carriers to use
Four complexes
NADH enter through complex I
FADH2 enter through complex II
CoQ: accepts electrons from both complexes I and II
formation of CoQH2: diffuses in the inner membrane to complex III
electrons transferred from CoQH2 to cytochrome c (protons released into intermembrane space
Once Cyt C reduced, diffusees in the intermebrane space, passes e's to CIV
Proton gradient = source of potential energy
Protons move back into matrix
energy harnessed if pathway opened through membrane; movement of protons through membrane used to perform work
Chemiosmotic Hypothesis:
potential energy of proton gradient released through transmembrane opening
Movement of protons through enzyme coupled with synthesis of ATP
ATP synthase
F0 subunit: forms channel in inner mitochondrial membrane (protons flow)
rotation converts energy of proton gradient into mechanical rotational energy --> rotation of F1 subunit in mitochondrial matrix
F1: catalytic unit that synthesizes ATP
Rotation causes conformational changes (synthesis of ATP)