DNP Case

outputs of glycolysis

2 pyruvate, 2 net ATP, 2 NADH

PDH complex outputs

2 acetyl CoA, 2 NADH, 2 CO2

TCA cycle output

4 CO2, 6 NADH, 2 FADH2, 2 ATP

through what mech is ATP created in glycolysis and CA cycle

substrate level phosphorylation

how is ATP mainly recycled

through oxidative phosphorylation

energy flow sequence in cellular respiration

glucose -> NADH -> ETC -> proton motive force -> ATP

what percent of energy in a glucose molecule is transferred to ATP

34%

how much ATP is made in cell resp

32

what does oxidative phosphorylation include

ETC, proton motive force, ATP synthase

where does oxidative phosphorylation occur

inner mitochondrial membrane and intermembrane space

what type of molecule has the most energy

fully reduced molecule

describe NAD+ in redox

oxidant, oxidizing agent, oxidized form

describe NADH

reductant, reducing agent, reduced form

reduction potential

how strongly a molecule wants to gain electrons (be reduced). electron atraction strength. electron transfer potential. more positive E is a stronger pull for electrons. more negative E means electrons want to be given away

what does high redox potential mean

strong oxidizing agent. really WANTS electrons

how are redox potentials written

for the reaction as a reduction. of oxidation is taken place, then the reaction is read backwards. oxidized form + e- = reduced form, and E tells you how much the oxidized form wants to gain electrons

strongest oxidant

most positive V

strongest reductant

most negative V

strongest oxidant (NAD+ or FAD)

FAD

strongest reductant (NADH + H+ or FADH2)

NADH + H+

driving force of ETC

electron transfer potential of NADH/FADH2 relative to O2. electrons are moving from a compound with lower affinity for electrons (weaker oxidants) towards compounds with higher affinities. Oxygen has the greatest so it is last

how favorable is ETC

super. like -220 KJ/mol

why is electron flow step wise

if it was all at once it would basically be a combustion bc such a high release of energy. stepwise allows for controlled energy release

what does electron flow power

proton pumping

where are protons pumped

into the intermembrane space

what is the proton gradient called

proton motive force

what powers complex 1

NADH

what powers complex 2

FADH2

where do electrons move towards

O2

which complexes pump protons

1, 2, and 4

what is the proton gradient

high H+ in intermembrane space and low H+ inside matrix

waht type of gradient is proton motive force

electrochemical

mitchell's proton motive force equation

deltaP = deltaPsi + deltaH

deltaP

proton motive force

deltaPsi

electrical gradient

deltaH

H+ gradient

how is ATP synthase embedded

top ring part is in the inner mitochondrial membrane but the rest hangs out in the matrix

where do protons first enter ATP synthase

the c ring

describe c ring rotation

super fast! like 100 revolutions per sec

how do protons neutralize

on a glutamate or aspartate residue

what does proton flow through synthase lead to

the release of tightly bound ATP

catalytic sites of ATP synthase

3 beta subunites

what is gamma subunit role

rotating shaft that interconverts the subunits

what causes rotation of gamma subunit

proton flow

beta subunit conformation cycles

1. Loose (nucleotides are trapped) 2. Tight (ATP is synthesized) 3. Open (ATP is released or can bind)

diff between oxphos and susbtrate level

oxphos requires O2 (consumed by ETC to generate proton motive force - NOT used directly in ATP symthase). substrate level requires a certain substrate to provide energy. oxphos only takes place in mitochondria

what is DNP

a weight loss tablet

effects of women who took DNP

elevated breathing, high temperature. after 6 hours her temp increased adn then there was no heart beat. it was not possible to ventilate her due to muscle rigidity

properties of DNP

has a pKa of 4.1 (mostly deprotonated O-) and is lipid soluble (can cross inner mitochondrial membrane into intermembrane space)

how does DNP work

in the intermembrane space it binds to a proton, and releases the proton in the matrix to become O-. this collapses the proton gradient and energy is released as heat instead of as ATP

type of molecule DNP is

uncoupler of oxidative phosphorylation

what normally happens to energy in PMF

transformed to kinetic energy in ATP symthase and then chemical energy in ATP

what happens instead in defficient PMF

turns into heat

waht do muscles need to contract

atp and calcium. atp binds to myosin head to detach it from actin, when atp is hydrolysized myosin is energized, contraction only repeats if ATP is there

what happens to muscles without ATP

myosin cannot detach from actin adn cross-bridges stay locked. this causes sustained contraction and muscle rigidity

why was DNP marketed as weight loss drug

when DNP decreases body ATP, body speeds up all catabolic pathways (like glycolysis), body also burns through fat stores

waht does DNP do to CO2 production and why

increased rate of CO2 production. all because catabolic pathways increase and cO2 is a byproduct of that

why does oxygen consumption increase

ETC is running at maximum speed and O2 is final electron acceptor in complex 4

example of a natural uncoupler

brown adipose tissue (good uncoupler)

explain brown fat

a type of fat that has a lot of mitochrondria and its job is heat production. essentially does what DNP does but good for maintaining body temperature in hiberating animals

difference between brown fat and DNP

brown fat is controlled, localized, and regulated by the body, as well as safe heat production

protein used in brown fat mechanism

uncoupling protein (UCP1) its a protein channel in the inner mitochondrial membrane that allows H+ protons to flow back into matrix

what is leigh syndrome

mutatation in subunit a of atp synthase. symptoms include vomitting, diarrhea, and dysphagia. high levels of pyruvate and lactate. abnormal brain MRI. hyotonia, dystonia, ataxia, visual loss. treatment is riboflavin and coQ10

what is hypotonia

floppy baby syndrom - decreased muscle tone

describe NADH through ETC

enters at complex 1. flows from 1 to 3 to 4 (all 3 complexes pump a lot of H+ which results in a large proton gradient)

describe FADH2 through eTC

goes from complex 2-3-4 but 2 does not pump protons so there is a smaller gradient

NADH ATP yield

2.5

FADH2 ATP yield

1.5

what is special about complex 4

O2 accepts electrons which forms H2O and keeps the cycle running

how does cytosolic NADH (from glycolysis) enter mitochondria

inner mitochondrial membrane is impermeable to NADH so cell uses shuttles to transfer its electrons instead.

shuttle in heart and liver

malate-aspartate shuttle - consists of two membrane transporters and four enzymes. electrons go through complex 1

shuttle in muscle

glycerol 3-phosphate shuttle - electrons are trasnported from NADH to FADH2 to Q to form QH2. electrons go through complex 2 (bc last owner of electrons was FADH2)

what about the NADH made in PDH complex

no shuttle needed. makes 2.5 ATP bc nADH

net total normal cell using malate-aspartate

32

net total normal cell using glycerol 3-phosphate

30

what happens if no protons can travel down gradient

ETC will be shut down bc gradient is too steep. this will also shut down PDH and TCA that rely on ETC to regenerate NAD+ and FAD. glycolysis CAN continue and turn pyruvate to lactate. if O2 is lacking, ETC will shut down which will shut down PDH and TCA