1. 1 Mitochondria and chloroplasts John F. Allen
SBS922 Membrane Biochemistry
Mitochondria and chloroplasts
John F. Allen
School of Biological and Chemical Sciences, Queen Mary, University of London 1

2. References Look in course resources on SBCS web site or go to
Second Year : Membrane Biochemistry
These slides and supplementary information from:

6. Bioenergetics, 3rd Edition
David Nicholls and Stuart J Ferguson
Academic Press · Published July 2002
Recommended text for 3rd year course Membrane Proteins.
Chapter 4 is good for Membrane Biochemistry lectures and practicals

7. Mitochondria (singular; mitochondrion).
– mitochondria power animal and plant cells
– mitochondria are "domesticated" bacteria
– during "domestication" - cell evolution - these bacteria relinquished many genes to the nucleus of the host cell...
.…and there are now few left (13 in the case of vertebrates, including mammals, including humans) encoding around 1 % of mitochondrial proteins
And it is always the same 1 %.....
Why?

9. Scientific Art From
Lane, N. (2005)
Power, Sex, Suicide: Mitochondria and the Meaning of Life

10. Mighty Mitochondria
copyright Odra Noel

11. A mitochondrion—one of many tiny power-houses within cells that control our lives in surprising ways
copyright Ina Schuppe-Koistinen

13. Goodsell, D. S. The Machinery of Life
Goodsell, D. S. The Machinery of Life. Springer-Verlag, New York and Berlin, 1993

16. Allen, J. F. (2003) Phil. Trans. R. Soc. B458, 19-38

17. I II
III IV
ATPase
Mitochondrial matrix
Inter-membrane space

18. Protein subunit encoded in mitochondrial DNA
Protein subunit encoded in nuclear DNA
Mitochondrial inner membrane H+
Direction of vectorial proton translocation
Direction of electron transfer

19. I II III IV ATPase Inter-membrane space NADH O2 H2O ADP NAD+ succinate
fumarate
ATP
Mitochondrial matrix

20. The mitochondrial theory of ageing
"Errors" in electron transfer - transfers to the "wrong" electron acceptor - occur at fixed frequency.
The products of these reactions damage mitochondrial genes, which then produce defective proteins, which then make more "errors" in electron transfer....damaging more genes, making more defective proteins....and so on.

22. Coda. Two views of mitochondria View 1
John Burn (Newcastle Institute of Clinical Genetics). Quoted in The Times, 9th September 2005
Mitochondria:
– “…are not part of the genetic material that we consider makes us as human beings.”
“My belief is that what we are doing is changing a battery that doesn’t work for one that does….Changing the mitochondria won’t affect the important DNA.”

23. Coda. Two views of mitochondria View 2
Nick Lane. Power, Sex, Suicide. Mitochondria and the Meaning of Life. Oxford University Press. Publication: 27th October 2005.
Mitochondria:
– “…give striking new insights into why we are here at all, whether we are alone in the universe, why we have our sense of individuality, why we should make love, where we trace our ancestral roots, why we must age and die––in short, into the meaning of life.”