bio lecture 5 + 6 (finla unit 1 material)

describe the 4 complexes

which complex pumps protons and how many?

which complex donates eletrons and what accepts them?

how does ATP synthase work?

what molecules carry electrons between complexes?

why is the electron transport chain important for aerobic respiration?

describe how glycolysis relates to cancer and diabtes

does oxidation of one molecule lose or gain electrons?

lose

does reduction of one molecule gain or lose electrons

gain

what is reduction potential

affinity of a redox pair for electrons relative to a standard measured as a voltage difference

low reduction potential =?

low affinity for electrons

high reduction potential =?

high affinity for electrons

how are electrons transferred from molecules?

electrons transferred from molecules of low potential to high (NAD+ gains to become NADH) (FAD becomes FADH2)

only NAD+ is accepting electrons in glycolysis

FADH2 is only used in citric acid cycle

does NADH?NAD+ favor oxidation or reduction

favors oxidation bc strong electron donor

is energy released or consumed when we go from high energy to low energy

from high energy to lower energy is releasing energy (low reduction potential to high reduction potential?)

energy that is released in membrane transport is used to pump protons across inner mitochondrial membrane

The electrochemical gradient is?

The electrochemical gradient is source we use for power of synthesis of ATP

energy + membrane is used to create chemical gradient and use atp synthase to make ATP using that chemical gradient as energy source

1st of 4 complexes that make up electron transport chain

electron transport chain

• transfer of electrons to complexes within chain results in pumping H+ into membrane space

which of the 4 complexes pump protons

1,3, 4

Where do protons start, and where do they end up

protons pumped from the mitochondrial matrix (most interior region of the mitochondria) across the inner mitochondrial membrane into the intermembrane space

how is electrochemical gradient created?

created from protons (H+) being pumped through

what’s at end of mitochondrial matrix being pumped?

ATP synthase, whats uses electrochemical gradient to make ATP

what electrons are donated to complexes

recieve electrons from NADH and FADH2

• NADH donates at complex 1 (10H+ ions across membrane) then produces 3 ATP/NADH theoretically (really 2.5) goes from 1,3,4 never touches complex 2

• FADH2 enters at complex 2 (6H+ ions across the membrane) goes 2,3,4 never touches complex 1, then produces 2 ATP?FADH2 theoretically (really 1.5)

does NADH or FAD pump fewer protons

FADH2 (provides less for electro chemical gradient so contributes less to the generation of ATP)

complex 1 for electron gradient

NADH dehydrogenase complex

• oxidizes NADH to NAD+ (donating electrons)

• NADH dehydrogenase complex accepts protons from NADH and then donates those molecules to is Q (aka ubiquinone)

ubiquinone

• electron acceptor

• accepts from NADH

• reduce ubiquinone

• hydrophobic so diffuse within inner mitochondrial membrane

what is each complex accepting from and what does it donate to and how mnay protons pumped

• complex 1 (NADH dehydrogenase complex) accepts from NADH and donates to Q. 4 protons pumped

• complex 2 (succinate dehydrogenase complex) accepts from FADH2 and donates to Q. no protons pumped

• complex 3

• complex 4

complex 2

• name is succinate dehydrogenase

• accepts from FADH2 and then oxadized to FAD

• donates to Q. (different Q molecule than in complex 1)

• no protons pumped

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complex 3

• name is cytochrome C reductase

• donors are GH2 molecules

• pumps 4 protons for every pair

• reduced bc accepting electrons

if donates protons it is, and if accepts protons it is?

donates protons oxidized, accepts protons reduced

cytochromes

• hydrophbic

• carry 1 electron at time

• if passing pair to cytochromeC uses 2 cytochromes

• carries them to next complex (cytochrome oxidatase)

if passing pair to cytochrome C how mnay used?

2 cytochrome C molecules

complex 4

• name is cytochrome oxidase

• accepts electrons from 4 cytochrome C and passes them to O2

• pumps 2H+ across membrane per electron pair

• donor is cytochrome c

• acceptor is oxygen to make h2o

what happens if no oxygen at end of electron transport chain

if no oxygen at end of complex 4 whole electron transport chain would stop bc we wouldnt be able to keep moving electrons through chain. if cant move them through then cant accept from NAD+ and FAD (FADh2 and NADH) cant regenerate FAD and NAD+ and need those for citric acid cycle and pyruvate dehydrogenase complex

electron flow NADH and FADH2

NADH→ complex 1 → Ubiquinone (Q) → complex 3 → cytochrome c → complex 4

FADH2 → complex 2 → ubiquinone (Q) → complex 3 → cytochrome c → complex 4

total protons pumped by NADH and FADH2 (one time)

NADH results in 10 total, FADH2 only pumps 6 total.

ATP synthase 2 part

F1 part

F0 part located in intermitochondrial,

• subunits dont rotate

F1 complex

gama subunit interacts with 3 pairs of Alpha beta subunits. alternating a b subunits

• empty means not binding with atp and not making it then binds to adp where phosphate comes in, thens snthazie atp then released where subunits go back to empty

• starts in empty (gama subunit closely associated with alpha beta pair),

• rotation of 3 steps in 120 degrees

• 3 states are empty, just made it and released it, trapping ADP and phosphate, and then making atp, atp gets released

electrochemical gradient also contributes to moving ADP into mitochondrial matrix and moving those protons in

total atp

• glycolsis is 2 atp per glucose molecule and 2 molecules of NADH,

• if O2 pyruvate goes ot pyruvate deheydrogenao complex and acetyl coa and makes 2 more nADH (2 for every glucose)

• 2 for every glucose, citric cycle, makes 6 NADH per glucose, and 2 FADH2 and 2 GTP

• NADH and FADH2 happens in mitochomndria so those molecules already in mitochondria, every NADH makes 3 ATP, 2FADH2 gives 2 ATP

• so total is 36 (reality 28-32 but theoretically 36)

• ATP rom gly not contriuted bc happens in cytosol

how do we get energy out

gly needed in anerobic conditions bc that how we get energy out (even more out if we have oxygen)

glyc in cancer

• cancer tissues have less o2 so relying on glyc to make ATP,

• tumor tissue has much higher level so glucose uptake

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glyc in diabetes

• type 1: cells produce hormones (insulin) are beta cells in pancreaus. to few beta cells to produce enough insulin. no insulin cells dont take up glucose well (results in lower blood ph) they rely on fats but not enough of it to help

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• type 2: singaling not working, don;’t respond well to insulin that gets released, develop insulin resistence, so more insulin is required to achieve same effects

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ketone body production

• if cells end up with low glucose, we need to make glucose from oxeloacitate, which wont be avaible for citric acid cycle. ketone bodies produced during prolonged fast or starvation, made from acetyl-coa, of the three acetone, acetoacetate, and b-hyboybutrate acetone is toxic.

• acetoacetate, and b-hyboybutrate lower blood ph (ketoacidotis)

• fine in moderation but not long term energy source

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