Bio exam 1 info Flashcards
Activation energy
Energy to get started, even thermodynamic favored chemical reactions require Ea
Enzymes characteristics
Enzymes lower activation energy in almost all chemical reactions in cells, the enzyme is not altered by the reaction, the enzyme does not cause reaction to occur, but it does increase the rate of reaction, enzymes increase free energy (in transition state), enzymes are proteins that act as catalysts for biological reactions
Ribozymes
All enzymes are proteins, but there are catalytic RNA molecules
Ligand
Molecule or ion that binds to another molecule (protein), this binding is very specific and can involve several weak bonds, causes protein to change shape, overall strong interaction
Cofactors
Nonprotein molecules or inorganic ions, often metal ions, that some proteins require in order to function, includes coenzymes and ATP
Binding affinity:
Strength of interaction
R group modification
Addition of a chemical group to an amino acid changes its interaction with nearby amino acids and the protein changes shape
Proteolysis
Some long proteins mush be shortened by breaking a peptide bond by hydrolysis and protein can be synthesized but not activated until appropriate time and location, it has an extra piece of itself- needs to me removed as it blocks the active site
Enzymes are slightly specific for their substrates (the reactants)
Substrate molecules bind to the “active site” of the enzyme
Enzymes have a 3D shape that determines the specificity(lock and key fit)
How enzymes work
Two different substrates enter into the active site on the enzyme(this is the very specific fit for the substrates and enzyme, once it goes through enzyme-substrate complex, the enzyme releases one product
Endergonic reactions can be driven by
Coupling to Exergonic reactions
An Exergonic reaction will release energy at ATP hydrolysis, that released energy can be used in Endergonic reaction to form products
Enzyme-substrate complex (ES) forms
Held together by hydrogen bonds, electrical attraction, or covalent bonds
Induced fit
Enzyme (e) may change when bound to the substrate but returns to its original form
E+S-ES-E+P
Enzyme original form and product released