ability to acquire and use energy.
capacity to do work.
2 Laws of Thermodynamics
- 1. Total amount of energy in universe is constant, energy cannot be created or destroyed, can only change forms.
- 2. Spontaneous direction of energy is from high quality to low quality, each conversion results in production of heat, which is unusable to do work.
refers to interaction between molecules which in turn result in formation of new molecules with different chemical and physical properties.
chemicals that enter into a reaction. (substrates)
chemicals that are present after the reaction.
result in products with more energy then reactants had.
2H + O -> H2O
result in products with less energy then reactants had.
H2O -> 2H + O
Characteristics of metabolic pathways
most reactions are reversible, all reversible reactions approach a state of dynamic equilibrium.
large molecules, such as carbohydrates, proteins, and lipids are broken down to smaller molecule. Energy is released and used for cellular work.
small molecules are assembled into large ones. A source of energy is required.
- *proteins that serve as catalysts
- *they are selective
- *they act of specific substrate
- *add -ASE to the end of substrate
- *they are denatured by high or low pH, chemicals, radioactivity and high temperature
Enzyme Structure and Function
active site is a crevice where the substrate binds to the enzyme during reactions. Reactant must reach a transition state in order for the reaction to proceed.
- the amount of energy needed to bring reactants to the transition state.
- *enzymes increase the rate of reactions by lowering the required activation energy.
Control of Enzymes activity
- 1. controlling the number of enzymes by speeding up or slowing down enzyme synthesis
- 2. inhibitors can bind with the active site.
- 3. allosteric enzymes have a regulatory site, where control substances can bind, to alter enzymes shape and activity.
- *If this control substance is the end product of a metabolic pathway, feedback inhibition occurs.
to assist enzymes
NAD, FAD; transport hydrogen and electrons
Inorganic metal ions
Fe++; transport electrons in ETS
energy carrier; Adenosine Triphosphate
- *energy input links a phosphate to ADP to form ATP.
- *ATP can donate a phosphate to another molecule (substrate level phosphorylation). That molecule then becomes primed and energized for specific reactions.
- *ATP becomes ADP after the loss of a phosphate.
2 kinds of Phosphoylation
- 1. substrate level- phosphate transported from one substrate to another.
- 2. electron transport
extract energy from chemical reactions involving inorganic reactants.
use light energy.
feed on autotrophs, each other and organic waste.
yields 36 ATP
- *C6H12O6 + 6O2 -> 6CO2 + 6H2O + E
- ^ ^ ^ ^ ^
- gulcose oxygen carbon water energy
4 series of reactions
- 1. glycolsis
- 2. prior to Krebs cycle
- 3. Krebs cycle
- 4. electron transport phosphorylation
glucose is broken down to 2 pyruvate. 2 ATPs, 2 NADH are formed
prior to Krebs cycle
pyruvate is converted to Acetyl CoA. 1 NADH, 1 CO2 is formed.
3 NADH, 1 FADH2, 1 ATP, 2 CO2 are formed.
Electron transport phosphorylation
32 ATPs are made.