Catalysis is the secret sauce of chemical reactions, speeding things up without getting used up. It's like a matchmaker for molecules, bringing them together and making magic happen faster. take this to the next level in living things.
These protein powerhouses are nature's catalysts, working their magic in our bodies. They're super picky about what they work with and can be turned on or off like a light switch. Understanding enzymes is key to grasping how life ticks at the molecular level.
Fundamentals of Catalysis
Catalysis and reaction acceleration
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Catalysis increases reaction rate without being consumed lowers activation energy provides alternative reaction pathway
Accelerates chemical reactions increases rate of product formation allows reactions under milder conditions (lower temperature, pressure) maintains equilibrium position
Catalysts facilitate catalysis remain unchanged after reaction can be reused multiple times (industrial processes)
Homogeneous vs heterogeneous catalysis
Homogeneous catalysis occurs with catalyst and reactants in same phase usually liquid phase (acid-catalyzed esterification)
Heterogeneous catalysis involves catalyst and reactants in different phases typically solid catalyst with liquid or gas reactants (catalytic converters, Haber process)
Differences: heterogeneous easier to separate homogeneous often uses milder conditions homogeneous generally more selective
Similarities: both increase reaction rate neither affect reaction equilibrium
Enzyme Catalysis
Enzymes as biological catalysts
Proteins with specific 3D shapes composed of amino acid chains often contain or prosthetic groups (heme in hemoglobin)
Catalyze biochemical reactions in living organisms highly specific for particular substrates operate under physiological conditions (body temperature, neutral pH)
Characteristics: high () recyclability regulation through cellular mechanisms ()
Enzyme structure and function
Enzyme specificity: perfectly fits substrate shape changes upon substrate binding
Active sites: specific region where catalysis occurs composed of amino acid residues determines enzyme's catalytic properties
Substrate binding: forms enzyme-substrate complex involves weak interactions (hydrogen bonds, van der Waals forces) orients substrate for reaction
Factors affecting enzyme activity
pH effects: optimal pH range for each enzyme affects ionization state of amino acid residues extreme pH denatures enzymes (pepsin in stomach acid)
Temperature effects: increased temperature raises reaction rate up to optimum excessive heat denatures enzymes cold temperatures slow activity
Other factors: substrate concentration follows enzyme concentration directly proportional to reaction rate presence of cofactors or coenzymes (NAD+ in dehydrogenases)