ETC

Question 1

What is the experiment which proved the location of the ETC

Answer 1

Isolate a mitochondria ->
Treat with mild detergant:
- Disolves the outer membrane. ETC still functions
Treat with strong detergant:
- dissolves both membrane. ETC does not function

therefore ETC within IMM

Question 2

What are the two types of carriers which we have in the ETC

Answer 2

mobile carriers
complex carriers

Question 3

What are the two mobile carriers within the ETC

Answer 3

Coenzyme Q (ubiquinone):
- Organic co enzyme non vitamiine dirrived
- carry reduction potentioals, can pick up / release 1 at a time
- uptakes 2 from C1 or C2 release 1 at a time to C3
- located within the IMM and can move within

Cytocrome C:
- Contain a heme unit which can carry 1 e- though redox of Fe3+ -> Fe2+
- moves between C3 and C4 - located outter edge of IMM

Question 4

How does the complex carriers function / how is energy moved through the ETC

Answer 4

Sequential redox reactions where 1 carrier is reduced and then oxidised passing e- to the next carrier.
Carriers throughout the ETC have progressivly higher reduction potenitals meaning they are more prone to beig reduced
Each step releases energy which is used to pump H+ until e- reaches O2 the terminal e- aceptor (highest reduction potenital)

Question 5

How does NADH and FADH2 move through the ETC + protons moved

Answer 5

NADH: C1 -> CoQ -> C3 -> Cyt C -> C4 - pumps 10H+
FADH2: C2 -> CoQ ->C3 Cyt C -> C4 - pumps 6H+

Question 6

What happens in complex 1 and 2 + movement from these complexes

Answer 6

C1: NADH is oxidised to NAD+ releasing 2e-, pumping 4H+

C2: FADH2 is oxidised to FAD+ releasing 2e-, no H+ pumped, also a component of the CAC

Moves via CoQ - uptakes 2e- moves to C3 in the Q cycle where 1 e- is released at a time to C3

Question 7

What happens in complex 3 and 4

Answer 7

C3: 1e- processed at a time from the Q cycle
releases 1e- into cyt C -> pumps 4H+ (per 2e-)

C4: recives 1 e- from Cyt C
reducing O2 and relesing 2H+ (per 2e-)
1/2O2 + 2H+ -> H2O
biologically 2 reduction potentials converted at a time: O2 + 4H+ -> 2H2O

Question 8

What is the effect of inhibiting the ETC

Answer 8

Inhibiting the ETC means No oxidised coenzymes to be reused in other pathways -> no ATP from other pathways
No H+ gradient to power ATP synthase -> low ATP

Question 9

What are 3 toxins of the ETC and what do they target

Answer 9

Carbon monoxide: binds where O2 should be locayed
Cyanide: Binds to carrier in complex 4
Rotenone: inhibits electron trannsfer from C1 -> CoQ