14. oxidation-phosphorylation Flashcards
What is oxidative phosphorylation?
is the process by which ATP is formed as a result of the transfer of electrons from NADH or FADH2 to 02 by a series of electron carriers
What is energy from high energy electrons used for ?
to pump protons from the mitochondrial matrix to the inter membrane space
What is the energy from proton flow used for?
to phosphorylate ADP to ATP
Electron flow in respiratory chain flows from
negative to positive redox potential
What do big jumps in redox potential indicate?
big changes in ΔG (free energy)
What are the 2 stages of oxidation phosphorylation?
electron transport and ATP synthesis
What happens during electron transport?
- electrons flow from NADH and FADH2 to O2 and
- respiration
- energy is used to pump H+ out of the mitochondrial matrix and into the inter membrane space
What happens during ATP synthesis?
- electrochemical gradient of H+ across mitochondrial inner membrane
- energy stored in this gradient can be used to synthesis ATP
What happens in the respiratory chain?
- electrons from NADH enter at complex 1
- electrons from FADH2 enter at complex 2
- electrons are handed down from higher to lower redox potential
How many subunits are in the respiratory chain and what are they?
- NADH-Q reductase
- Ubiquin one
- Cytochrome C reductase
(then to cytochrome C) - Cytochrome C oxidase
(then to ATP synthase) resulting in the formation of water
Electrochemical gradient - where are there more protons?
more protons in inner membrane than the matrix
How is a concentration gradient formed?
more protons in inner membrane forms an electrical field making matrix side more negative
Proton flow back into the matrix is coupled to…
ATP synthesis
Electron transport is…
energetically favourable
When coupled to proton pumping it is..
energetically unfavourable
protons are pumped across the membrane as…
electrons flow through the respiratory chain
What subunits of ATP synthase form the starter?
a, b, alpha ,beta
What subunits of ATP synthase form the rotor?
c, gamma, e
What turns the rotor?
the flow of electrons which causes a conformational change leading to ATP synthesis
What is the p/o ratio?
a measurement of the coupling of ATP synthase to electron transport
What is the p/o ratio when NADH is oxidised to NAD+
2.5
What is the p/o ratio when FADH2 is oxidised to FAD
1.5
What is the final balance from 1 glucose molecule?
4 ATP, 10 NADH + H+ +2FADH2
How many molecules of ATP does 1 glucose molecule yield?
30-32
What are OXPHOS diseases?
- common degenerative diseases
- involve components of oxidative phosphorylation
- are mutations in mitochondrial or nuclear DNA
- pathology usually becomes worse with age
- symptoms usually appear In tissues with highest ATP demands
