1.4 enzymes Flashcards
explain how substrate concentration affects enzyme activity?
if enzyme concentration stays constant, then as substrate concentration increases so does rate of reaction.
this is until the reaction plateaus as all the active sites are occupied and therefore at this point enzyme concentration/active sites becomes the limiting factor
define a catabolic enzyme?
an enzyme that breaks larger substrate into smaller products
define an anabolic reaction?
an enzyme that breaks larger product into smaller substrate
define turnover number?
the number of substrate molecule turned into product per unit of time
describe (in terms of bonds) how active sites denature?
vibrations break apart the hydrogen bonds in the active site
describe how enzyme concentration affects enzyme concentration graph?
as enzyme concentration increases, so does the rate of reaction.
they are directly proportional until it (plataeus??)
describe how substrate concentration affects an enzyme activity graph?
as substrate concentration increases, so does the rate of reaction until a certain point where the graph plateau’s.
describe the activity of an enzyme bound on a membrane surface on a temperature graph? explain why this is?
the enzymes now make direct contact with the substrate and product is formed faster. - higher total product and same higher optimum as alginate beads.
describe the activity of immobilised enzymes in alginate beads on a temperature graph? and explain why this is?
the enzyme activity will continue to increase beyond the optimum, due to the alginate gel fills/supports the active site (stoping it from denaturing) and allowing for more ESC.
describe the effect pH has on an enzyme activity graph?
enzymes have a narrow optimum pH range, and the graph increases and decreases at the same rate either side of the optimum, leaving a ’n’ shaped graph.
describe the general graph of temperature affecting enzyme activity?
increased temperature gives the molecules more kinetic energy, and therefore the enzymes and substrate move around quicker and have a higher chance of colliding and forming enzyme substrate complexes.
higher temperature = higher rate of reaction (steepness)
describe the process by which lactose get removed from milk?(alginate beads)
as milk flows through the column, the substrate (lactose) diffuses into the alginate matrix and forms ESC with lactase, then glucose and galactose diffuses out of the membrane and leave the column with milk.
describe the process of a biosensor?
detects molecules
transducer detects the chemical change, amplifier amplifies it, and display.
describe what a biosensor is? give an example
a biosensor detects biologically important molecules at low concentrations (blood glucose levels in a diabetic person)
describe what occurs at 25 degrees on an enzyme activity graph?
as time increases so does the amount of product formed, there is a lower degree of steepness but they are directly proportional until denaturing temperature
describe what occurs at 37 degrees on an enzyme activity graph?
as time increases, so does product formed, there is a steep curve at the beginning until is reaches a peak and then starts to plateau at the highest amount of product formed
describe what occurs at 60 degrees on an enzyme activity graph?
as time increases so does product formed, at the beginning there is the steepest curve/rate of reaction until it begins to plateau at a lower amount of product formed
do enzymes have a high or low turnover number?
enzymes have a high turnover number
explain how an enzyme substrate complex occurs in relation to the charges? how does the pH affect this?
the charges on an amino acid must attract the charges on the substrate molecule
the charges on an enzymes active site are affected by free h+ ions and OH- ions therefore if there is too many of one or the other, the enzyme and substrate would repel one another.
explain how enzyme concentration effects the enzyme activity graph?
once product leaves active site, enzymes reused and therefore a low number of enzymes are needed to catalyse a lot of reactions (high turnover number)
this is because there are more active sites available to catalyse more reactions.
explain the effect pH has on the rate of an enzymes reaction inside of the optimum?
due to the narrow optimum pH:
small changes can cause reversible changes in structure and possible inactivation
large changes can cause the enzyme to denature
explain the effect pH has on the rate of an enzymes reaction outside of the optimum?
due to the narrow optimum pH:
small changes outside of the optimum alters the rate of reaction but not the structure of the enzyme
large changes denatured the enzyme
explain what occurs at 25 degrees on an enzyme activity graph?
kinetic energy is low, substrate and enzyme collide less often therefore resulting in less enzyme substrate complexes and product is produces slower
explain what occurs at 37 degrees on an enzyme activity graph/product formed?
there is higher kinetic energy, therefore enzyme and substrate collide more often resulting in more successful enzyme substrate complexes and product is formed quicker
as it levels off, there is no more substrate left to convert, and substrate concentration is now the limiting factor
