Mitochondrial morphology and ultrastructure in skeletal muscle

Published on October 31, 2018   35 min

Other Talks in the Category: Methods

0:00
I'm Martin Picard from Columbia University. Today, I'll be telling you about mitochondrial morphology and ultrastructure in skeletal muscle.
0:09
Mitochondria are the origin of complex life, there are two main cellular compartments that we can look into. One of them is the cell nucleus which contains the genes that encode for proteins that provide structure for the cells, and if we look into the cytoplasm there are organelles including mitochondria. Mitochondria take the oxygen that we breathe in and the food substrates that we consume, and transform these into cellular energy that is necessary to power cellular activities. An important point is that the mitochondria and the nucleus exchange information on a regular basis, which is important for the regulation of cellular responses to stressors and to energy levels. There is evolutionary evidence that without mitochondria, the ancestor of today's eukaryotic cell could not have existed, and the evolution of multicellular life required the incorporation of the alphaproteobacterium which was then to become the mitochondria with its own genome. That afforded sufficient amounts of energy, we can see in the graph on the bottom left in picowatts per genome, the eukaryote which was able to evolve complex multicellular life has more energy per unit of cell.
1:22
But what do mitochondria look like? Here we have a cell time-lapse image which shows that mitochondria are extremely dynamic organelles, mitochondria are in fact living microorganisms that populate the cell cytoplasm. This big round structure in the middle with the little cartoon of the chromosomes is the nucleus, and that's where the genetic material is contained and these squiggly 'spaghetti' structures in the cytoplasm are actually the mitochondria. We can appreciate how dynamic they are, how much movement there is, and there are processes of fusion and fission that are constantly happening. Why is that relevant?
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Mitochondrial morphology and ultrastructure in skeletal muscle

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