Metabolism I Flashcards
define Catabolic
large molecules break down into smaller ones
Is Catabolism exergonic and endergonic?
energy being released- exergonic
Anabolism also known as synthesis requires
energy input–endergonic
Define Anabolism
small molecules are made into larger and more complex molecules
How does Substrate limeted reaction regulate itself
regulation by changing [A], [B], [C] and [D
product inhibiton and feedback are two types
Substrate limited reaction is often a what inhibition
allosteric inhibition
Substrate-limited reaction is often at a highly
exergonic steps
,** feedback inhibition** is inhibited by
the final product
Homeostatsis
balancing the final product with the cell’s needs
When it comes to substrate limited reaction, product inhibition is inhibited by
an immediate product
Enzyme limited reaction is regulated by
modulating corresponding enzymes
At what step does Enzyme limited reaction happen?
rate-limiting steps
Changing enzyme availability increases or decreases the
rate of synthesis or degradation
Spatial organization also known as
compartmentalization
How can you change enzyme active in an enzyme limited reaction? Name 4
Allostery, reverasible covalent modification, reverasal binding, irreversible covalent modification,
Where does Allostery inhibitors often bind to?
often binding a place that is not the active site
What are the 4 levels of spatial organizations in enzymes
Seperate individual enzymes, multi0enzymes complex, substrate channeling, and mebrane-bound enzyme system
In terms of spatial organization, What can individal enzymes do
they have independent enzymatic reactions
in seperate individual enzymes, substrates and intermediaties
must diffuse
Multi-enzymes complex are enzymes that need to
diffuse and form complexs
For multi-enzyme complex, substrate and intermediates
do not need to diffuse
Substrate channeling is easy to
regulate coordinately
What does Substrate channeling do the enzyme reaction rate
boosts the reaction rate
Membrane bound enzyme system has
minimal diffusion and many are large complexes
the most common form of energy is
adenosine triphosphate (ATP
What is the metabolic pathway
The transformation of ingested food to energy and simple compounds, or the synthesis of complex molecules, is performed by a series of enzymatic reactions. Collectively, these enzymes, and their substrates and products
Glycolysis is
first pathway used to degrade sugars and it is located in the cytoplasm
pyruvate
a 3 carbon keto acid that is the final product of glycolysis
Monod-Wyman-Changeaux model
concerted change
Koshland model shows
Sequential change:
subunits “flip”
individually
biological oxidation often looses
2H+ and 2e-
the citric acid or tricarboxylic acid cycle (TCA), i
second pathway in the degradation of sugars.
Where is the citric acid cycle located in
in the matrix of the mitochondria
What are the different types of modulators
activators, inhibitors, homotrophic, hetrotrophic
Homotrophic
substrate= modulator, allosteric site= active site
Allostery fine-tunes
enzyme activity
most allosteric effectors affect
affect only K M , but some change Vmax
when the allosteric enzymes are co cooperative the graph has a
sigmodial curve for V/[S]
cooperative
phenomenon displayed by enzymes or receptors that have multiple binding sites where the affinity of the binding sites for a ligand is increased or dewcrease
What does the binding of the binding of 1 subunit do?
other subunits affinity to the substrate increasing
pancreatic trypsin inhibitor (6-kDa polypeptide tightly binds, where
to the active site
What is an example of reversible binding of other proteins
pancreatic trypsin inhibitor (6-kDa polypeptide
ancreatic trypsin inhibitor (6-kDa polypeptide) prevents
any trypsin that is prematurely activated in the pancreas from digesting it
what are other metabolic pathways? Name 3
nonidentical foward and reverse pathways, compartmentalization, and commitment steps
commitment steps are when
certain enzymes are key regulatory points
How are Nonidentical forward and reverse pathways regulated?
when certain steps are independently regulated providing direction to the rest of pathway
cascade of proteolytic activation is made
as inactive percusors
biological oxidation is often catalyzed by
dehydrogenase
Biolgical oxidation gains electrons
O
every oxidation must be accompained by
a reduction
Oxidation-reduction redox reaction involves
a electron transfer between 2 molecules
a reduction gains
electrons, H and loses O
CO2 is the most
oxidized from of carbon found in living organisms
In C-H bonds, the more electronegative
C “owns” the 2e - shared with H.
In C-O bonds,
O owns 2e-
the catabolic pathways are
oxidative reaction sequences
What are the functional groups of that can participate in redox reactions
hydroxyl
aldehyde
ketone
carbonyl
amino
amide
methyl
ether
disulfide
thioester
ester
sulfhydryl
phosphory
Oxidation requires
specialized electron carriers
H+ is soluble but e-
is insoluble in aqueous soltion
During cellular respiration or oxidation what molecules act as electron carriers
NAD + (nicotinamide adenine dinucleotide) and FAD (flavin adenine dinucleotide)
Lactater is oxidized to
pryuvate
NAD + is reduced to
NADH
Pyruvate is reduced to
lactate
NADH is oxidized to
NAD+
Which carbon is the 2H+ and 2 e- are removed from the lactate
2nd carbon
What are 2 strategies to decrease ∆G
Make K eq «_space;1
o Couple an endergonic rxn with an exergonic rxn
Oxygenases is a subclasses of enzymes for what reactions
redox reactions
Oxygenases uses oxygen as what
a substrate
Oxygenases catalyze reaction where oxygen atoms are directly
incorporated into the product
oxygenases forms what type of new group (hint: 2 groups)
a new hydroxyl or carboxyl group
What reaction does Oxidases catalyzes
oxidation reactions
Oxidases molecular oxygen serves
as the e- acceptor
