Final: ETC and oxidative phosphorylation

Question 1

what organelle produces ATP?

Answer 1

mitochondria

Question 2

mitochondria anatomy

Answer 2

inner and outer membrane

Question 3

where does oxidative phosphorylation occur?

Answer 3

inner mito membrane

Question 4

what is oxidative phosphorylation (meaning of each word)?

Answer 4

oxidation = molecules give up electrons
phosphorylation = addition of phosphate group to ADP to make ATP

Question 5

oxidative phosphorylation overview sentence

Answer 5

make ATP by donating electrons to complexes in the inner mitochondrial membrane

Question 6

what are the complexes?

Answer 6

proteins or lipids coupled with metals (EX: iron and copper)

Question 7

what is the final electron acceptor

Answer 7

oxygen

Question 8

overall purpose of oxidative phosphorylation?

Answer 8

create a proton gradient which is used to create ATP

Question 9

What does ETC start with?

Answer 9

NADH and FADH2

Question 10

where do we get NADH and FADH2 from?

Answer 10

1) glycolysis in cytoplasm
2) citric acid cycle in mitochondria
3) fatty acid oxidation in mitochondria

dehydrogenases help generate NADH and FADH2

Question 11

how do NADH and FADH2 from cytoplasm (glycolysis) enter mitochondria for ETC?

Answer 11

the malate-aspartate shuttle (enter as NADH)

glycerol-3-phosphate shuttle (enter ETC at FADH2)

Question 12

what can we do with NAD+ created by complex I

Answer 12

can be re-used by dehydrogenases to create more NADH

Question 13

relationship between CAC and ETC

Answer 13

they share a step! complex II (succinate dehydrogenase is also in CAC)
their activity rises and falls together

Question 14

what happens in hypoxia (no oxygen)

Answer 14

ETC is interrupted, ATP synthesis doesn’t happen

Question 15

what does ETC produce?

Answer 15

the passing of electrons creates an electrical current which provides energy that allows protons to be pumped out of the mitochondria and into the space between the outer and inner mito membrane

Question 16

how do complexes push protons?

Answer 16

as electrons move through, the complexes change conformation to push protons across

Question 17

what do protons use to get across the mito membrane?

Answer 17

mito membrane is impermeable to protons

they use F0 proton channel attached to enzyme F1

Question 18

ADP/ATP antiport

Answer 18

pumps protons out of mitochondria and into cytoplasm

ATP leaves, a new ADP goes in to start cycle again

Question 19

energy payoff for NADH

Answer 19

1 NADH makes 3 ATP

this is bc NADH activates 3 proton pumps (1, 3, and 4)

Question 20

energy payoff for FADH2

Answer 20

1 FADH2 makes 2 ATP

bc it skips complex 1

Question 21

those payoffs are called

Answer 21

P/O (phosphate: oxygen) ratios

bc they require oxygen as final electron acceptor

Question 22

P/O ratio

Answer 22

rate of ATP produced per oxygen consumed for each molecule

these are approximates

Question 23

is ETC under hormonal control?

Answer 23

NO!

it is controlled by energy levels

Question 24

high ATP

Answer 24

slow down ETC

Question 25

high ADP

Answer 25

means low energy, speeds up ETC

Question 26

drugs do what to OX phos

Answer 26

break it up via uncoupling or inhibition

Question 27

uncoupling

Answer 27

ETC is normally coupled with ATP synthesis (they happen together) uncoupling agents break this link by inserting their own proton channels (ionophores) inter inner mitochondrial membrane or by carrying protons back into mito matrix

Question 28

uncoupling agents cause bypass of what?

Answer 28

F0 (now F1 can't phosphorylate ADP into ATP) | they dissipate proton gradient

Question 29

inhibition

Answer 29

chemicals/drugs inhibit components of ETC STOPS flow of electrons through ETC leads to decrease in ATP synthesis

Question 30

what builds up during inhibition?

Answer 30

electron donors: NADH and FADH2 this means body will stop making more metabolic rate falls

Question 31

mitochondria inner membrane...why is it folded?

Answer 31

to increase surface area for ETC!

Question 32

energy requiring step of ATP synthesis

Answer 32

ATP release from ATP synthase requires most energy | ATP synthesis itself doesn't require energy

Question 33

flow of protons through ATP synthase

Answer 33

flow of protons through F0 subunit causes rotation of F- plus gamma. This rotation drives conformational changes in beta subunits that mediate binding of substrates, ATP synthesis, and release of ATP.

Question 34

proton gradient requirements (2)

Answer 34

functional ETC and a proton-impermeable membrane

Question 35

ETC and ATP synthesis inhibition

Answer 35

if one is inhibited, so is the other

Question 36

malate-aspartate shuttle

Answer 36

Malate to mitochondrial matrix Malate to oxaloacetate Oxaloacetate then leaves mitochondria as aspartate to reset the cycle In cytoplasm aspartate then becomes oxaloacetate again

Question 37

glycerophosphate shuttle

Answer 37

transfers NADH in cytosol to mitochondria since inner mito membrane is impermeable to NADH and NAD+