Metabolism Flashcards
Metabolism
Sum of all the chemical reactions that occurs within a living cell/tissue/organism
Use of metabolism
used to build or break down chemical to make other chemicals
used to liberate or store energy used to do cellular/ organismal function
Metabolite
Different molecules in a pathway
Advantages of multi-step pathways
multiple points help to control how fast the reactions occur
Ability to divert ‘pathway intermediates’ to other pathways to do things
changes to metabolism through evolution
1st Law of thermodynamics
Energy cannot be created or destroyed. energy can only be transformed/converted
2nd of thermodynamics
Changes in Entropy can never be negative. As more of enrgy is transformes, more of it is watsed (lost as thermal energy)
Free Energy (G)
The amount of energy in ‘the system’ available to do useful work
final state -initial state
The reactants have G (initial state)
The products have G(final state)
True/ False
True
what happens when the reactants have more free energy than the products
G will be less than zero
These reactions are exergonic = energy releasing. exothermic (negative)
it took LESS energy to break the bonds in reactants compared to the energy released when the bonds are formed
These reactions are spontaneous, not necessarily instantaneous (all at once)
when bonds form, does it take energy or release energy?
when bonds are formed it releases energy
when bonds break, does it take energy or release energy?
when bonds break, it takes energy
what happens when the reactants have less free energy than the products
G will be greater than zero
Endergonic = energy consuming. endothermic(positive)
it takes MORE energy to break the bonds in reactants compared to the energy released
when the bonds were formed in the products.
Why does ATP take less energy to break?
This is because of the electronegativities of the close oxygen, they want to move away from each other. ATP is easier to break
Exergonic reactions can be coupled with those that are endergonic?
True/False
True
Transition State
This is an unstable configuration
Activation Energy
The minimum amount of energy required to reach the transition state and result in a chemical reaction
What do enzymes do
Enzymes speed up the rate of reactions (without being consumed) by lowering the activation energy.
Lowering activation energy means making the bonds easier to break.
G is unaffected by enzyme
what are substrates
Reactant molecules
what are catalysts
substance that increases the rate of a chemical reaction without itself undergoing permanent changes
enzymes are catalyst
Induced-fit model
Theory that the active site and the substrate are not perfect matches for each other
step by step process of induced-fit model
- Substrates enter the active site; Enzymes changes the shape so its’ active site can fit the substrate
- Substrates are held in active site by weak bonds like hydrogen and ionic
- Substrates are converted to products
- Products are released
- Active site is available for two new substrate molecule
What are ways for enzymes catalyst to speed up reactions?
a. Holding two substrates close together in the right orientation
b. Stressing substrate bonds through movement of the protein
c. ‘microenvironment’ of the active site speeds up reaction
d. Some amino acids directly participate in reactions
what happens when the 3d shape of a protein is altered
When the 3d shape of a protein is altered, the protein stops working (Denaturation - protein unfolding)
What can denature a protein?
A. Increased Temperature (speed up a reaction until the protein denatures)
differences in #of hydrogen bonds
# of disulfide bridges
B. pH
Affecting the # of ionic bonds with the protein
Types of substrate-enzyme binding
Normal
Competitive Inhibition
Non-Competitive Inhibition
Competitive Inhibition
the inhibitor molecule deceives the enzymes by resembling the original substrate. It binds to the active site, so the original substrate can’t bind. This makes the reaction slower or stop
Non-competitive Inhibition
The inhibitor molecule binds elsewhere on the enzyme and changes its shape. The original substrate cannot bind because the active site is changes. An example is feedback inhibition. stops reaction maybe*
Allosteric Activation
A regulatory molecule(not substrate) binds to a regulatory site(sides)which stabilized the active site
Allosteric Inactivation Site
A regulatory molecule(not substrate) that binds to a regulatory site (sides) which stabilizes the inactive site
Cooperativity
when a substrate binds one unit (inside), which stabilizes the active site on the other unit
