6.4 Enzymes speed up metabolic reactions by lowering energy barriers
How does an enzyme catalyze a reaction?
It lowers the activation energy allowing reactants to absorb less energy than they would need to absorb without the enzyme in order to reach transition state.
What would happen if enzymes didn't regulate chemical traffic through pathways of metabolism?
The cell would become congested because many chemical reactions would take a long time
Does the shape of the enzyme change at all when binding with the substrate?
Yes, as the substrate enters the active site, the enzyme changes shape slightly due to interactions between the substrates chemical groups and the chemical groups on the side chain of the amino acids that form the active site. This provides a more snug fit between the enzyme and the substrate.
coenzyme
cofactor in an organic molecule
enzyme
macromolecule that acts as a catalyst
Formation of new bonds releases (more/less) energy than was invested in the breaking of the old bonds
more
Do enzymes change the change in free energy and switch the type of reaction?
no
cofactor
nonprotein helpers for catalytic activity
active site
pocket/groove on the surface of the enzyme where catalysis occurs. place where the substrate binds to the enzyme
enzyme-substrate complex
temporary complex formed when enzyme binds with its substrate
How does temperature affect the conditions of enzyme activity?
rate of reaction increases with temperature up to a point -above this temp, the speed of reaction increases because thermal agitation disrupts bonds that stabilize the active shape -below this temp, the enzyme changes shape
substrate
reactant enzyme acts on
enzyme + substrates has a ______ reaction with the enzyme substrate complex which has a _____ reaction with the product: the enzyme + products
reversible reversible
What does the specificity of the enzyme result from?
shape
Why do molecules absorb thermal energy?
so the reactants accelerate and collide more often as well as more forcefully.
True or false: only certain substrates can fit in a specific enzyme's active site
true
When changing one molecule into another, it usually involves the contorting of a starting molecule into a highly (stable/unstable) state before reaction can begin.
unstable
when is an enzyme saturated?
when concentration of substrate is high enough that all active sites are engaged. As soon as one leaves another enters
transition state
when molecules have absorbed enough energy for the bonds to break. (unstable condition)
How does pH affect the conditions of enzyme activity?
when the solution is too acidic/too basic it denatures the protein
What determines the rate of a reaction?
Activation Energy
induced fit
Brings chemical groups of the active site into positions that enhance their ability to catalyze the chemical reaction. change in the shape of an enzyme so it fits more snug with the substrate. {caused by entry of substrate}
catalyst
chemical agent that speeds up reaction without being consumed by the reaction
Activation Energy
energy required to contort the reactant molecules so the bonds can break -amount of energy needed to push reactants uphill so downhill part can occur