enzymes Flashcards
(17 cards)
what do catalysts do ?
they speed up the rate of reaction
are catalysts altered by reactions
no
why are some reactions slow ?
because of an energy barrier
what is the activation energy ?
the amount of energy required to start the reaction
what does reaction rate depend on ?
the frequency at which the reactant collide
energy of the reactants
what is the enzyme substrate complex held together by …
bonds and electrical attraction
what are prosthetic groups ?
non-amino acid groups bound to enzymes
what are cofactors ?
inorganic ions
what are co enzymes ?
small carbon-containing molecules; not bound permenently to enzymes
the rate of a catalysed reaction depends on substrate …
concentration
what are inhibitors ?
these are molecules that bind to the enzyme and slow down reaction rates
what is meant by irreversible inhibition ?
this is when an inhibitor bonds to the side chains in the active site- this permanently inactivates the enzyme
what is meant by reversible inhibition ?
the inhibitor bonds to the active site and prevents the substrate from binding
what do competitive inhibitors do ?
they compete with the natural substrate for binding sites
-when the concentration of competitive inhibitor is reduced, it detaches from the active site
what are noncompetitive inhibitors ?
these bind to the enzyme at a different site (not the active site)
what do noncompetitive inhibitors do ?
bind to a site away from active site and this causes the enzyme to change shape and it alters the active site. the inhibition is usually reversible but it is not influenced by substrate conc
what are isoenzymes ?
enzymes that catalyse the same reaction but have different properties, such as optimal temperature
