Exam 3: Weeks 9-11 Flashcards
citric acid cycle products
3 NADH, 1 FADH2, 1 GTP/ATP, 2 CO2
regulatory enzymes in citric acid cycle
isocitrate dehydrogenase (+ for ADP, - for NADH and ATP)
alpha-ketoglutarate dehydrogenase (- for NADH, ATP, succinyl CoA)
high succinyl coA will slow down…
ETC
dehydrogenase catalyzes…
an oxidation step
oxidation steps in citric acid cycle
4; 1 produces FADH2, 3 produce NADH
high ADP means energy is…
low
can i keep selling seashells for money officer?
pneumonic for citric acid cycle
acetyl-CoA starts the…
citric acid cycle
dehydrogenases in citric acid cycle
I AcKnowledge, SUCky Men
Isocitrate
Alpha-Keto
SUCcinate
Malate
ETC: 1 NADH creates…
2.5 ATP
ETC: 1 FADH2 creates…
1.5 ATP
proton gradient from ETC is in…
intermembrane space
NADH and FADH2 comes from…
mitochondrial matrix
complex I
NADH
complex II
FADH2
what happens to electrons as they pass through ETC?
they become lower and lower in free energy hence why they are passed on
final electron acceptor
removes low energy electron and binds them to free H+ to form water
synthesis of ATP in mitochondria is driven by…
a protein gradient
reoxidation of NADH and FADH2 indirectly creates a protein gradient
ATP synthase
“complex V”
carnival ride (subunit C) - loads H+ and rotates to power the rest
beta subunit - ATP produced
alpha subunit - stabilize the beta subunits
loose: ADP and inorganic phosphate (Pi) are mingling (ADP + Pi)
tight: ADP and Pi bind to produce ATP
open: ATP released
conformations change by rotating of the gamma stalk caused by rotating of C subunit
stator
holds ATP synthase in place
E cell
E red - (E ox)
PLUG IN AS GIVEN
what is oxidized? what is reduced? spontaneous reaction?
OIL RIG - use this to figure out what goes on which side of balanced equation
pick the half reaction with more negative potential (lower E value) will be oxidized
greater E value will be reduced
g deg: phosphorylase action
MAIN ENZYME: asdjfa;dkj
cleaves alpha 1,4 linkages and creates glu-1-phosphate
will cleave 7-8 glucose monomers (whatever is 4 monomers away from the branch)
glu-1-phos –> glu-6-phos by phos
phosphoglucomutase
g1p –> g6p
branch of glycogen
alpha 1,6 linkage
g6p + water
glucose + inorganic phosphate
once glycogen cleaved by g1p…
4 glucose monomers still attached - NOT wanted!
transferase! takes 3 from the end and puts on end of glycogen chain
alpha 1,6 glucosidase cleaves using water to create FREE GLUCOSE with the one that remained after the transferase passed through
after degradation, phosphorylase…
keeps cleaving the glycogen chain until it reaches the core
glycogen synthesis
MAIN ENZYME: glycogen synthase
first, need to activate! with UDP glucose (glucose + UTP = UDP)
synthase transfers glucose from UDP glucose onto growing chain
glycogenin is the CORE - autoglycosylation can also transfer glucose (essentially, can participate in chain elongation)
adds 7-8 monomers to core
long chain isn’t convenient!! we must branch
branching enzyme! takes added glucose monomers and creates alpha 1,6 linkage to the 4th carbon from the right end of the core
next branching point much be at least 4 units away from the last branching points
a to b
covalent modification (something is getting phosphorylated)
T to R
allosteric modification (something about external factors will affect being pushed into these states)
most active
phosphorylase a (phosphorylated) in R state
least active
phosphorylase b in T state
T state
active site is covered
phosphorylase b
not phosphorylated
liver is source of…
glucose mobilized between meals; liver stores glucose
phosphorylase a is dominant
muscle…
energy reserve for muscle control; muscle CANNOT supply glucose because it does not contain glucose-6-phosphatase
phosphorylase b is dominant
high conc of glucose reverts…
R to T state since a high conc of glucose means that the liver doesn’t need to call on glycogen stores
high AMP means we need energy
R state which pushes forward glycogen degradation
high ATP means…
energy is needed
what does protein kinase A do?
phosphorylates!!
reciprocal regulation of glu deg and syn
protein kinase A and protein phosphatase 1
protein kinase A
phosphorylates through turning on kinases
glycogen phosphorylase (b–>a)
glycogen synthase (a–>b)
starts the breakdown of glycogen because we need energy in the form of free glucose
phosphorylase <3 phosphorylation
protein phosphatase 1
dephosphorylates!
glycogen phosphorylase (a–>b)
glycogen synthase (b–>a)
starts glycogen synthesis to make glycogen and remove stores of free glucose
hormones
act on kinases
insulin
means high glucose level
start glucose synthesis
glycogen synthase kinase!! will become inactivated when insulin is high to produce glycogen to keep synthase in the a state
inactivated by covalent modification through phosphorylation
glucagon and epinephrine
send out same signal
low glucose level (glucose is gone)
phosphorylatine
activates phosphorylase kinase BUT inactivates
glycogenesis enzymes
glycogen synthase
branching enzyme
glycogenolysis
glycogen phosphorylase
transferase
alpha 1,6 glucosidase
PPP phases/products
phase 1: oxidative phase - make NADPH
phase 2: non oxidative phase - makes 5C sugars (ribose-5-phosphate)
mode 1
when we need ribose 5 phosphate MORE than NADPH
non-oxidative phase
cell division since r5p is needed MUCH more
mode 2
need ribose 5 phosphate and NADPH equally
oxidative phase then an isomerase to transform ribulose to ribose
ex: when cell is rapidly dividing since r5p is needed for nucleotide materials and NADPH for biosynthetic needs - would more need r5p MORE but still “equal” - acceptable answer according to labrake
mode 3
need lots of NADPH»_space; r5p
oxidative state - easy
isomerase will create r5p but we do not need it!
end up with glycolysis intermediates that can go into further oxidative steps go into gluconeogenesis (??)
repeat until cell is happy
needed when synthesizing fatty acids
mode 4
need NADP and ATP
oxidative state
glycolysis intermediates and go forth with glycolysis
will create pyruvate for citric acid cycle and electron transport chain to make ATP
needed during oxidative stress
NADPH
reduces reactive oxidative species
PPP effectors
NADP+ (+)
fatty acid acyl CoA (-)
NADPH (-)
first step of PPP
dehydration of glucose-6-phosphate
how much more ATP is generated from glucose-6-phosphate, compared to glucose, when it is metabolized by the glycolytic pathway?
1
glycolysis: 4 ATP products- 2 ATP react = 2 net ATP
starting at g6p: 4 - 1 = 3
therefore 1 more is generated
why? we skip the first reaction that takes an ATP (????)
glutathione protects against
reactive oxidative species
fatty acid synthesis
- transport from mitochondria: acyl-conitine
- activation
acc1 and 2
regulated covalently and allosterically
acc1
cytosol
acc2
mitochondria
inhibition of acc2 will…
push forward beta oxidation; therefore, negative effectors of acc2 will push it forward
fatty acid synthesis
acetyl coA in mitochondria is converted to citrate and transported to cytoplasm where it is reconverted
insulin dephos….
acc1 and acc2 become active
activation of FA
acyl-coA synthetase - ATP is required
steps of beta oxidation
oxidation
hydration
oxidation
thiolase
products of beta oxidation
1 nadh, 1 fadh, 1 acyl coa
example where glucose in the body is low: prolonged starvation
ketone bodies can be used as alt source of energy!
especially important for the brain!
keto diet is meant for epilepsy
nutritional ketosis
not that bad but can’t last forever because it makes the blood acidic
ketoacidosis
dangerous for individuals with type 1 diabetes
which ketone body contributes the most energy
3-hydroxybutyrate
complex that does not contribute to proton gradient
complex ii
