Lesson 3.3 - Environmental Impacts on Enzyme Function 𖦹⋆｡°✩

Question 1

what can a change to the molecular structure of an enzyme result in

Answer 1

may result in a loss of enzyme function

Question 2

what is the shape of enzymes

Answer 2

enzymes have unique 3D shapes known as the conformational shape/tertiary structure

Question 3

what is denaturation

Answer 3

changes in the conformational shape of the enzyme

Question 4

what can lead to denaturation

Answer 4

༻ changes in environmental temperature
༻ changes in environmental pH

Question 5

what happens when an enzyme is denatured

Answer 5

the catalytic ability of the enzyme is lost or severely decreased. denaturation is usually irreversible

Question 6

in some cases, denaturation is reversible. what happens in this case

Answer 6

the enzyme will regain catalytic activity

Question 7

what can affect the efficiency of enzyme activity and reaction rates

Answer 7

༻ environmental temperature
༻ environmental pH
༻ concentration for substrates and products
༻ enzyme concentration

Question 8

what are optimum temperatures

Answer 8

range in which enzyme-mediated reactions occur the fastest

Question 9

when do reaction rates change with regards to temperature

Answer 9

reaction rates change when optimum temperatures aren’t maintained

Question 10

what happens when there is an environmental increase in temperature

Answer 10

༻ initial increase in reaction rates
༻ increased speed of molecular movement
༻ increased frequency of enzyme-substrate collisions

Question 11

what happens when temperatures increase outside of the optimum range

Answer 11

temperature increase outside of optimum range results in enzyme denaturation

Question 12

what happens when there is an environmental decrease in temperature

Answer 12

༻ slowed down reaction rate
༻ decreased frequency of enzyme-reaction collisions
༻ does not disrupt enzyme structure, no denaturation

Question 13

what does pH measure

Answer 13

the concentration of hydrogen ions in solution measured on a logarithmic scale

Question 14

what do small pH changes equal

Answer 14

small changes in PH values equate to large shirts in hydrogen ion concentrations

Question 15

what is optimum pH

Answer 15

the range in which enzyme-mediated reactions occur the fastest

Question 16

what happens when you change the pH outside of the optimum range

Answer 16

enzyme activity will slow/stop
༻ enzyme denaturation can occur as a result of increases/decreases outside of optimum

Question 17

what can changes in hydrogen ion concentration disrupt

Answer 17

can disrupt hydrogen bond interactions that help maintain enzyme structure

Question 18

how can concentration of substrates and products affect reaction rate

Answer 18

༻ initial increase in substrate concentration increases increase reaction rate because more substrates mean more opportunity to collide with enzymes
༻ increased product concentration decreases opportunity for substrate addition because matter takes up space, so more product in an area means a lower chance of enzyme substrate collisions = slower reaction rate

Question 19

what does substrate saturation result in

Answer 19

results in no further increase in rate; reaction rate will remain constant if saturation levels are maintained

Question 20

how does a change in enzyme concentration impact reaction rate

Answer 20

༻ less enzyme = slower reaction rate, less opportunity for substrates to collide with active sites
༻ more enzyme = faster reaction rate, more opportunity for substrates to collide with active sites

Question 21

what do competitive inhibitors bind to

Answer 21

the active site

Question 22

what are competitive inhibitors

Answer 22

molecules that can bind reversibly/irreversibly to the active site of the enzyme

Question 23

what do competitive inhibitors do

Answer 23

competes with the normal substrate for the enzyme’s active site

Question 24

what happens if the inhibitor concentrations exceed substrate concentrations

Answer 24

reactions are slowed

Question 25

what happens if inhibitor concentrations are significantly lower than substrate concentrations

Answer 25

reactions can proceed normally

Question 26

what happens if inhibitor binding is irreversible

Answer 26

enzyme function will be prevented

Question 27

what happens if inhibitor binds reversibly

Answer 27

enzyme can regain function once inhibitor detaches

Question 28

can molecules only bind to the enzyme’s active site

Answer 28

no, enzymes have regions other than the active site to which molecules can bind

Question 29

what are these alternate sites called

Answer 29

allosteric sites

Question 30

what are noncompetitive inhibitors

Answer 30

༻ do not bind to active site, bind to allosteric site

Question 31

what does binding to the allosteric site cause

Answer 31

binding causes conformational shape change and prevents enzyme function because the active site is no longer available

Question 32

what can increasing substrate NOT do

Answer 32

cannot prevent effects of noncompetitive inhibitor binding