enzymes Flashcards
what type of biomolecules are enzymes?
proteins
are there certain organisms that do not have enzymes?
no, they are present in all living organisms
what does BIOLOGICAL CATALYSTS mean?
it means that enzymes speed up reactions
why is it said that enzymes can be recycled?
beacuse they can speed up a reaction and remain unchanged at the end, which means they can be used over and over again
what are the functions of enzymes?
enzymes can either break down large molecules into smaller ones, build up large molecules from small ones or convert a molecule into another one
why do enzymes break down large molecules into smaller ones?
so these can be absorbed and then used by the body. This function is important in nutrition
how do enzymes build up large molecules from small ones?
by joining them together to speed up the formation of storage and structural molecules
how do enzymes convert a molecule into another molecule?
by adding or removing atoms or groups of atoms
what is the enzyme’s ACTIVE SITE?
the active site is the place in the enzyme where the substrate is going to fit in, where the reaction takes place
how is the shape of the active site mantained?
it’s mantained by bonds between different parts of the molecule
why do we say that enzymes are specific?
because each enzyme catalyses only one type of reaction with a specific substrate, as only one type of substrate fits in an enzyme’s active site.
there’s one enzyme for each reaction
what type fo reactions do enzymes catalyse?
enzyme catalyse reactions in which substrates are converted into products
why do substrates fit in the enzyme’s active site?
because they have a complementary shape
what is it meant by the “lock and key model”?
it means that the enzyme and the substrate combine like a key entering a lock to form an enzyme-substrate complex.
the substrate fits right into the enzyme’s active site like a key fits into its lock, however, if it’s not the correct substrate, it wont fit, like a key won’t fit/open a lock that isn’t its own
how is the activity of an enzyme determined?
by measuring its rate of reaction
how can the rate of reaction be measured?
by either measuring how much product is formed or by measuring how much substrate is used over a period of time
what is the rate of reaction of an enzyme?
is the speed of reaction measured in quantity of product or substrate per unit of time
what factors influence enzyme’s activity?
temperature and pH
what is meant by “optimum temperature”?
the optimum temperature is the temperature at which the maximum rate of reaction occurs
what is the optimum temperature for humans?
around 37C
what is the optimum temperature for plants/fungi?
around 20C
what is the optimum temperature for bacteria?
around 90C
what happens when we increase the tempearture of an enzyme’s controlled reaction?
the rate of reaction increases as the enzyme and the substrate molecule have a greater kinetic energy, which means they move around more quickly so they have higher chances of colliding into eachother
what happens if the tempeature of an enzyme’s controlled reaction is increased too much?
the bonds holding the enzyme molecule together start to break dow, the shape of the active site changes, the substrate can no longer fit: the enzyme is DENATURED
what is pH?
pH is a scale that goes from 0 to 14. from 0 to 6.9 the substance s acidic, at 7 the substance is neutral and from then up til 14 the substance is alkaline
what is meant by “optimum pH”?
the optimum pH is the pH at which the maximum rate of reaction occurs
what happens when there are huge changes in the pH level?
the bonds that hold enzymes together are broken, the active site’s shape is altered, the substrate no longer fits: the enzyme is DENATURED
what happens with the rate of reaction when an enzyme is denatured?
it becomes 0
