Enzymes- lecture #9 Flashcards
what does metabolism do?
manages all material and energy resources of the cell
what is a catabolic pathway?
_____,_____,
releases energy as ATP
breaks down large molecules/polymers
in a useable form
what is an anabolic reaction?
_____,_____,
uses energy
builds large molecules/polymers
unfavorable because it uses energy
what do all metabolic practices rely on?
enzymes, in order to make them happen efficiently
what can energy be used to do?
work (such as rearrange matter)
what 2 laws govern thermodynamics?
energy can be transferred and transformed but may not be created nor destroyed
some energy is lost as heat
what is a spontaneous process?
(-) delta G (more stable)
creates disorder
exergonic
releases energy (heat)
why do we want disorder?
because the molecules will interact more and hit each other, creating heat
what is a non spontaneous process?
(+) delta G (less stable)
creates order
endergonic
requires energy (absorbs)
do we want enthalpy (delta H) to be positive or negative? why?
we want enthalpy to be negative, because it will release heat
is the entropy of the universe always increasing or decreasing?
entropy of the universe is always increasing
does (+) entropy create disorder or order?
it creates disorder, we want this
what happens to entropy when catabolic reactions release energy?
entropy increases
what happens to entropy when anabolic reactions require energy?
entropy decreases
enzymes functions to do what?
Lower the activation energy of a reaction allowing products to be produced more quickly
what else can increase the rate of a reaction? why do we not want it to happen all the time?
heat, however, all reactions would see an increase in rate (non specific) so we don’t want this to happen all the time
why is activation energy needed?
to destabilize the bonds of the reactants so they are readily able to break
what is the process of a bond breaking?
heat gets absorbed to provide energy
(energy required to break a paperclip)
transition state is reached when enough energy is absorbed
(bending the paperclip at first, hard to do)
bonds eventually break and energy will be released
(gets easier to bend and eventually snaps)
process of a substrate entering an enzyme
enzyme begins with empty active site, substrate enters into the active site (attaching with weak bonds), the strained substrate bond reacts with water (converting reactants to products), enzyme releases the product, enzyme is ready to catalyze a new reaction
why do enzymes act on a particular substrate?
shape of the active site caters to the shape of the specific substrate
what is the induced fit hypothesis?
substrate binds to an active site and both the substrate and active site change creating an ideal, close fit
this strains substrate bonds making them easier to break
what does the enzyme need to get the reactant out of the product?
needs some energy
how many substrates do enzymes act on per second?
acts on thousands or even millions of substrate molecules per second
what is critical to enzymes function?
shape
what may affect the shape of the enzyme?
temperature and pH value
what happens if the temperature is higher then optimal value?
denatures the enzyme rendering it, non -functional
what happens if the pH is slightly higher or lower then optimal pH?
enzyme function is impaired
why do most enzymes require cofactors?
coenzymes help recruit substrates
what are competitive inhibitors?
resemble the substrate
block the substrate from entering the active site
irreversible
what are non-competitive inhibitors?
do not resemble the substrate
bind to the enzyme but not in the active site
reversible
what is an important metabolic regulator
feedback inhibition
what is feedback inhibition?
when a cell produces more product then it needs
the product can inhibit the enzyme
The hydrolysis of ATP forming ADP and Pi has a G= -30.5kJ/mol. What can you conclude about ATP hydrolysis?
endergonic reaction
spontaneous reaction
