Four graphs, and in every one the question is the same: what is limiting the rate at this end of the axis?
A temperature curve looks like a single phenomenon and is really two, pulling in opposite directions. Which one is winning depends on which side of the optimum you are standing.
Warmer molecules move faster, so enzyme and substrate collide more often and with more energy. Rate climbs.
Past the optimum, vibration breaks the weak bonds holding the fold. The active site distorts and rate collapses.
The rise is gradual, the fall is steep — and the fall is permanent. Cold slows an enzyme; heat destroys it.
Tap each part. The distinction between what is destroyed and what survives is the point.
Tap the active enzyme, the agent, the broken bonds, the denatured chain, or the panel on the right.
Four graphs. In each case, work out what is limiting the rate at the left-hand end and what is limiting it at the right.
Both inhibitors slow the reaction. Only one of them can be defeated by adding more substrate, and that difference is visible on a graph.
Shaped like the substrate, so it occupies the active site. Excess substrate wins the competition and the maximum rate is unchanged.
Binds an allosteric site and reshapes the active site indirectly. Substrate cannot compete for a site it does not share, so maximum rate falls.
Many drugs and poisons are enzyme inhibitors — and cells use reversible inhibition themselves to regulate metabolic pathways.
Tap a node to light up its connections. The pink dashed link explains every plateau in this lesson.
Every effect on this map reaches the rate through the same structure: the active site.
Drag a term into a gap, or tap a term and then tap a gap. Two terms belong nowhere.
Every enzyme works fastest at its temperature and pH. Beyond that point the weak bonds holding the fold break, the enzyme becomes , and for most enzymes the change is . As substrate concentration rises, the rate eventually plateaus because every active site is occupied and the enzyme is — enzyme concentration has become the factor. A inhibitor resembles the substrate and binds the active site, whereas a inhibitor binds at an site and changes the shape of the active site.
Single best answer. You get the reasoning as soon as you commit.
Biology by Bradford