basic intro to Mitochondria and chloroplasts

1. MITOCHONDRIA AND
CHLOROPLASTS

2. Energy Conversion
• Mitochondria convert the chemical energy
of reduced carbon compounds into ATP.
• Chloroplasts convert light energy to the
energy of reduced carbon compounds
• Fundamental to both processes is an
electron transport chain, where energy is
passed from compound to compound in
coupled oxidation:reduction reactions

3. Mitochondria
2 membranes
Outer Membrane - has
large aqueous
channels made of a
protein called porin -
permeable to most
small molecules
Inner Membrane -
impermeable to ions
and small molecules
except by specific
membrane-transport
proteins

4. Mitochondria
2 compartments
• MATRIX - enzymes -
TCA cycle, DNA - several
copies, ribosomes, tRNA,
etc
• INTERMEMBRANE
SPACE
Inner Membrane is folded
into cristae,that greatly
increase its surface area.
This is where you find the
Electron Transport Chain
(ETC), ATP synthase,
transport proteins to allow
substances in to matrix
Fig 1-11

5. Mitochondrial Structure
How many compartments
do mitochondria have?
Which letter corresponds
to:
• the matrix?
• a crista?
• the intermembrane
space?
• the outer membrane?
• the inner membrane?
Where would you find the
DNA? the ribosomes?
C
E
B
A
D

6. • The ETC is found on the inner membrane
• High energy electrons are passed along the ETC
generating a proton gradient across the inner
membrane
• H+ gradient drives ATP synthesis
ELECTRON TRANSPORT CHAIN:

7. Mitochondria have 2 membranes
Chloroplasts have 3 membranes
There are 3
compartments
…what are
they?

8. Chloroplast Thylakoid membrane –
proteins of ETC, ATP
synthase
• Inner membrane –
membrane transport
protein for Rubisco
• Outer membrane -
porin
• Stroma – enzymes for
Calvin Cycle,
chloroplast DNA.

9. Chloroplasts

10. Plant Cell
Fig 13-26

11. Chloroplasts vs Mitochondria

12. These are mitochondria

13. So are these

14. Chloroplasts have different forms too
Thylakoids
Mitochondria

15. Antenna complex
chlorophyll
Resonance energy
transfer
Reaction center - site of charge separation
2H2O
O2 + 4 H+

16. Charge separation at reaction center
Takes 10-6 sec to complete!

17. Donation of high energy e- to e-
transport chain
From last slide
Ends at resting state
ECB 14-35

18. Photosynthetic e- transport is vectorial
Splitting of water leaves H+ in thylakoid space
B6/f complex e- to plastocyanin moves H+ from stroma to thylakoid space
e- to FNR reduces NADP in stroma, consumes H+ in
stromal
4
4
2
Net result is synthesis of NADPH and generation of H+ EC gradient
ACIDIC and + charge

19. Summary of
light reactions
in plants, algae
and cyanobactia
EC gradient used to synthesize
ATP