Presentation is loading. Please wait.

Presentation is loading. Please wait.

Lecture 12 Energy Conversion: Mitochondria and Chloroplasts

Similar presentations

Presentation on theme: "Lecture 12 Energy Conversion: Mitochondria and Chloroplasts"— Presentation transcript:

1 Lecture 12 Energy Conversion: Mitochondria and Chloroplasts

2 Chemiosmotic coupling:
the common pathway used by mito, chloroplasts and procaryotes ATP (chemi) Membrane transport (osmotic) Large amount of internal membrane in mitochondria and chloroplasts

3 Chemiosmotic coupling

4 Electron transport processes
High-energy Low-energy Photosystems: drive electrons in opposite directions Electron transport chain

5 Mitochondria move along MT
Mitochondrial plasticity

6 MT wind along axoneme in development
and then disappears and mito fuse… Fixed in position

7 Biochemical fractionation of purified mito
Study different proteins in each compartment Process large numbers of mito at the same time Low osmotic strength Cristae of the inner membrane unfold Outer membrane (no folds) break

8 Oxidative phosphorylation
ATP synthase Respiratory enzyme complexes

9 F0F1 ATPase, 500 kd F1 Lollipop head
Proton causes rotation and rubbing Of two sets of proteins against each Other: rotating stalk proteins and Head proteins F0F1 ATPase, 500 kd F1 Lollipop head >100 ATPs Per minute

10 Reversible coupling device
ATP synthase can also function in reverse to hydrolyze ATP and pump H+ Reversible coupling device

11 Plastids A proplastid from a root tip cell of a bean plant
Three amyloplasts (leucoplasts) or starch- Storing palstids in a root tip cell of soybean Purine and pyrimidine synthesis, aa synthesis FA synthesis All take place in plastids!


13 Inner membrane is not folded
Electron transport chains, photosystems, ATP synthase are present in thylakoid membrane

14 ATP synthase protrudes from into the matrix from the inner mitochondrial membrane ATP synthase Protrudes From the thylakoid Membrane into The stroma

15 Carbon fixation reactions (dark reactions):
Photosynthesis Photosynthestic electron transfer reactions (light reactions): Chlorophyll engergizes an electron using Light energy Electron comes from H2O and O2 is a by-product ATP synthesis and NADPH Carbon fixation reactions (dark reactions): Ribulose bisphosphate carboxylase

16 The antenna complex and photochemical reaction center
in a photosystem “Funnel”

17 A dividing mito

18 Various sizes of mitochondrial genomes
Nucleoids: similar to bacterial DNA circular ,000 nt

19 Suggested evolutionary
pathway for the origin of mitochondria

20 Human mitochondria genome: 16,569 nt. Sequenced in 1981.
Dense gene packing--not much regulatory sequences Relaxed codon usage--only 22 tRNA (30 in cytosol), many tRNAs recognize any one of the four Nt in the third (wobble) position 3. Variant genetic code-- 4 of the 64 codons have different meanings

21 More than 20 chloroplast genomes have been sequenced Similarity to bacteria is striking

22 In higher animals, the progeny contain only maternal mito.
In 2/3 higher plants, chloroplasts are also maternally inherited In other plants, pollen chloroplasts enter the zygote-biparental-variegation

23 Mitochondria import lipids
Chloroplasts make their own Mito converts imported lipids To cardiolipin (inner membrane)

24 Summary Chemiosmotic coupling and electron transport Mitochondria are plastic and can be motile Oxidative phosphorylation and ATP synthase Plastids and chloroplasts Photosynthesis, antenna and reaction center Mitochondrial and chloroplast genomes Inheritance of organelle genomes and biosynthesis

Download ppt "Lecture 12 Energy Conversion: Mitochondria and Chloroplasts"

Similar presentations

Ads by Google