Bioenergetics

Question 1

how many respiratory chains does human mitochondrial DNA produce

Answer 1

16

Question 2

what occurs in the mitochondrial matrix

Answer 2

TCA cycle
beta-oxidation
urea cycle
amino acid synthesis
mitochondrial protein synthesis

Question 3

what starting materials does the TCA cycle produce

Answer 3

amino acids
porphyrins (haem, chlorophyll)
purines and pyrimidines

Question 4

what is the inner mitochondrial membrane primarily composed of

Answer 4

protein

Question 5

features of the outer mitochondrial membrane

Answer 5

highly permeable
analogous to bacterial outer membrane
rich in porin and helical membrane proteins

Question 6

features of a voltage dependent anion channel

Answer 6

privides low barrier to exchange ATP/ADP
the pore is lined with a positive charge
contact sites between IMM and OMM

Question 7

how does the OMM interact with other organelles

Answer 7

via mechanical links

Question 8

what is mitochondrial trafficking

Answer 8

movement of mitochondria along microtubules
driven by kinesin and dynein

Question 9

how are the motor proteins linked to the mitochondria

Answer 9

Miro - integral OMM protein
Milton - adaptor protein

Question 10

function of mitochondrial contact site

Answer 10

exchange of lipids between organelles
mediate Ca2+ signalling from ER to mitochondria

Question 11

features of the IMM

Answer 11

site of energy generation
rich in proteins involved in respiratory chain
evolved to optimise restricted diffusion and localisation of reactions
contains transporters to move substances out into the cell

Question 12

what does the F1 donate to in the F1F0-ATP synthase

Answer 12

its the water soluble head
responsible for ATP biosynthesis

Question 13

what does F0 donate to in the F1F0-ATP synthase

Answer 13

transmembrane domain
couples proton transport to catalytic cycle
two half channels
proton transport link to transport

Question 14

function of MICOS (mitonchondrial contact sites)

Answer 14

drives membrane invagination
mix60delta large lamellar structure

Question 15

what is MICOS composed of

Answer 15

Mic10
Mic60

Question 16

features of Mic10

Answer 16

2TMD with TMD Glycine motif and positive loop
forms large oligomeric complexes
requires cardiolipin

Question 17

why is there such elaborate geometry

Answer 17

localisation of reactions:
ETC localised on cristae
efficient substrate transprort H+ gradient localised
restricts membrane diffusion gradient

Question 18

what are both IMM and OMM both poor in

Answer 18

sterols

Question 19

features of Mic60

Answer 19

forms the core of the complex
makes contact with the OMM

Question 20

function of ATPase dimerization

Answer 20

drives membrane curvature
abolish dimerization - bridging membranes

Question 21

ATP/ADP shuttle features

Answer 21

RRRMMM nucleotide binding motif
2 x 6 TMD/dimer

Question 22

what is Em

Answer 22

a measure of a chemical species ability to acquire electrons and thereby be reduced

Question 23

what does a high Em indicate

Answer 23

a high affinity for electrons

Question 24

what can be denoted from Em

Answer 24

the potential at which the compound is half oxidized and half reduced

Question 25

how many electrons do flavins carry and what is their deltaEm

Answer 25

2
0.2V

Question 26

features of ubiquinone

Answer 26

2 electron carrier
membrane bound - large isoprenoid chain
deltaEm of 0.045V

Question 27

features of FeS centres

Answer 27

1 electron carrier - irrespective of amount of Fe atoms
linked via Cys/His
delta Em of 200-250mV

Question 28

what are the delta Em’s of haem a/b/c

Answer 28

a - 385mV
b - 0.07mV
c - 0.254mV

Question 29

how do electrons travel the distance between redox centres

Answer 29

quantum tunnelling

Question 30

function of transverse helices

Answer 30

coordinate conformational change
stabilize complex

Question 31

how many electrons pass through the complex for every 4 H+

Answer 31

2 electrons

Question 32

where are the ubiquinone binding sites on complex III

Answer 32

opposite sides of the bilayer, P and N