unit 1,enzymes Flashcards
what are enzymes?
biological catalysts, they speed up chemical reactions, without getting used up or changed in the process, they lower the activation energy
what are enzymes made of?
enzymes are proteins with a 3D structure
What does an enzyme have a specific shape for ?
To fit together with the substrate to form an ES complex , they are complementary to one and other
What is the lock and key model?
It states that the shape of the active site is exactly complementary to the specific substrate molecule, they fit together to form an ES complex
What is the induced fit model ?
The shape of the enzyme is not exactly complementary to the substrate, the active site changes shape slightly to fit around the substate molecule, to form an ES complex
How does enzyme concentration affect enzyme concentration?
-More active sites are available so more substrate collisions can take place forming more ES complex’s , increasing the rate of reaction.
- the rate of reaction begins to have no effect when all the substrates are used up so there is no more substrates to fit into the active sites
How does substrate concentration effect enzyme action?
-increase rate of reaction as there are more substrate molecules so there are more collisions that take place to form more ES complex’s
- rate of reaction stops as all the active sites will be used up so no more ES complex’s can form
What is the effect of temperature on enzyme action?
- when temperature increases, there is more kinetic energy so molecules move faster, increasing number of collisions forming ES complex’s
- until optimum temperature is reached then enzyme will denature and substrate and active site will no longer fit together
What happens when the enzyme reaches optimum temperature
Increasing the temperature no longer effects rate of reaction
What happens when the enzyme denatures?
The molecules vibrate too much , and bonds are broken which maintain the tertiary structure. The active site changes shape and no longer and no more ES complex’s can be formed as the substrate will no longer fit
How does PH effect enzymes
Above or below the optimum temperature the H ions and the OH ions will be disrupting the ionic bonds effecting the tertiary structure , changing shape of the active site
What happens at extreme PH
The active site changes shape and no more ES complex can be formed as the substrate no longer fits, the enzyme denatures
What ions do acidic have
H+
What ions do alkali have
Oh-
What is competitive inhibition ?
-Have a similar to shape to the substrate molecules
-compete with the substrate to bind with enzyme blocking the active site , preventing formation of the ES complex
