enzymes and an intro to metabolism Flashcards
(26 cards)
what is newtons law of second thermodynamics
when energy changes from the amount of useful energy decreases and the amount of disorder / cheos increases
what do you call useful energy
Gibbs free energy
disorder / cheos is called
entropy
what are the 2 kind of biological processes that take place to put order in the disorder ?
1.exergonic
2.endergonic
(must go see the graph that show each of them in page 145)
what is the source biological processes
biochemical reactions
name the 2 energy transformations in biochemical reactions ?
- exergonic biochemical reaction
-endergonic chemical reaction
do biochemical reaction often have massive activation energy .
yeah !
cells uses powerful protein catalysis called enzymes to do what :
lower the activation energy of biochemical reactions , greatly increasing the rate of reaction.
ways in which enzymes and chemical catalysis are the same :
1-speed up chemical energy by lowering the activation energy.
2-they can only speed up the reaction that are possible .
3-they aren’t used up or permanently modified by the reaction they catalyze
Characteristics of specific enzymes(2) :
1- enzymes are specific to a very small number of reactant called subtrates foe enzymes
2- enzymatic activity is often regulated by the cell .
what do we call the reactives(réactif) of an enzyme reaction?
substrates
how are enzymes specific to one substrate ?
- enzymes a folded into a very unique 3D structure
the 3D structure of an enzyme will always have a pocket .What is it called?
active site (where the reaction will take place )
(2)the active site will only allow the correct substrate to enter because :
1- it has a very specific shape
2-the electrical charges of the amino acids R-group in the active site are complementary to those of the enzymes substrates both in their polarity (+/-) and their location.
(steps)how do enzymes catalyze reactions?
1- substrate/s enter the active site .
2-enzymes changes shape which either force the substrates to close together or put stress on the bond of a substrate promoting the reaction.this is called : transition state
3- the product/s no longer fit in the active site and are leleased .the enzymes return to its original shape .
enzyme function relies on what :
the correct 3D structure
enzymes only function if they have the correct :
tertiary struct. and this struct depends on its environment
what causes an enzyme to change its 3D struct and denature the enzymes?
many environmental condition the enzymes did not evolve to work.
if an enzyme no longer have the correct shape what happens?
they will not be able to catalyze the reaction
which environmental factors?
voir livre
how does the cells regulate enzymes ?
1) cells regulate the synthesis of enzyme depending on if they are needed or not .
2)cells synthesize some enzymes in an in active form (proenzymes)
3)enzymatic activity can be increased or decreased by allosteric regulation .Often uses feedback inhibition.
4)enzymes can be inhibited by competitive inhibition.
enzyme regulation method num 1: synthesis based on need
- some are synthesised when they are needed
*more enzyme = more catalysis reaction . less enzymes = less catalysis reaction.
enzyme regulation method num 2: synthesis of inactive enzymes (proenzymes )
-they will only be activated once they are in the correct environmental conditions .
-if an enzyme is dangerouse this will make sure that it is only active at the correct location where it is safe to use.
enzyme regulation method num 3: allosteric regulation
-allo mean other than
-Some enzymes have other places than the active site where allosteric regulator molecules can bind to them .
-when they bind the allosteric regulator will change the shape of the enz.
- the active site no longer have the correct structure.
