Chapter 8 Flashcards
(18 cards)
metabolic pathways
sequences of chemical reactions that break down or build up molecules in the body. They include pathways for carbohydrates, fats, and amino acids.
endergonic
building small molecules into large and requires input of energy (anabolism)
exergonic
breaking large molecules into small and releases energy (catabolism)
ATP
coupled to allow energy to be transferred and not risk losing energy
ATP hydrolosis
exergonic: couple to an endergonic reaction and energy goes from ATP to the anabolic reaction
ADP->ATP
endergonic, couple an exergonic reaction and the energy needed to build ATP can come from the catabolic reaction
ATP structure
adenine nucleobase, ribose sugar, 3 phosphates- bonds are phosphoanhydride bonds are high energy, ADP: 2 phosphates, AMP: 1 phosphate, more phsophates= higher energy, ATP relatively unstable due to electron repulsion in phosphates
Types of energy
potential, kinetic, bond
Free energy (G)
free energy for an individual reaction is constant, endergonic: increase in free energy as its absorbed, exergonic: decrease in free energy as its released
enzymes
biological catalysts, lower activation energy (heat cannot be used because proteins will denature), make it easier to get to transition state: here reactant bonds are less stable and easier to make new bonds of reactant. can introduce physical stress to weaken existing bonds and make new bonds easier to make or bring 2 reactant close together in a way the new bonds are easier to make. substrate binds to enzyme active site
substrate/enzyme binding
substrate binds enzyme-> enzyme-substrate complex-> reaction-> enzyme product complex-> products released-> enzyme ready to bind substrate
induced fit model
IMF of substrate makes the enzyme tighten around it, this keeps the substrate in place until the reaction has finished, products are released from enzyme because they are not held as tightly as substrate
enzyme catalyze reaction by:
introducing physical strain to substrate, putting substrate in perfect orientation for reaction to occur, introducing chemical charges (form its own amino acids in active site)
enzyme regulation
inhibitors, activators changing amount or location of enzyme
feedback inhibition
end product of pathway is an inhibator for enzyme of an early step
competitive vs non-competitive inhibitors
bind to active site(compete with substrate) or bind elsewhere and affect shape of active site
allosteric regulation
conformational change from other molecule binding
environmental conditions
pH can affect protein folding, and that affects enzyme activity. increasing temp. increases reaction rate, too high of temp, can cause denaturation and destroy enzyme activity
