MITOCHONDRIA THE UNUSUAL YET USEFUL ORGANELLE

MITOCHONDRIA THE UNUSUAL YET USEFUL ORGANELLE

Mitochondria are known as the powerhouses of the cell. They are organelles that act like a digestive system which takes in nutrients, breaks them down, and creates energy rich molecules for the cell. They generate adenosine triphosphate or ATP. ATP is the chemical energy “currency” of the cell that powers the cell’s metabolic activities.

Mitochondria are unusual organelles. They contain their own unique genome. They synthesise ATP for the cell to work and divide independently of the cell in which they reside. They have quite nice resemblance with their ancestors.

Where did these complex and unique things come from?

The mitochondrion is different from most other organelles because it has its own circular DNA and this is similar to that present in eukaryotes.  It also follows an apparent case of endosymbiosis. According to theories of evolution, millions of years ago small, free-living prokaryotes were engulfed by a host organism but were not eaten up perhaps because they were able to resist the digestive enzymes of the host organism. Over time, the descendants of the engulfed prokaryote developed into mitochondria, and the work of these organelles — using oxygen to create energy — became critical to eukaryotic evolution. Mitochondria are the tiny descendants of bacteria that inhabit each of your cells. Researchers have found that there are striking similarities to some modern prokaryotes, even though they have diverged significantly since the ancient symbiotic event.

What does this special organelle do?

Since many of the chemical reactions happen on the inner membrane, the increased surface area creates more space for reactions to occur. Mitochondria release cytochrome C, which activates Caspase, one of the chief enzymes involved in destroying cells during apoptosis. Mitochondria also have a special role in making cells die (apoptosis). This may sound strange, but it is vital for the processes of growth and development of the body. The outer membrane has many protein-based pores that are big enough to allow the passage of ions and molecules as large as a small protein. On the contrary, the inner membrane has much more restricted permeability. They also effectively burn your food in a carefully controlled way to produce that chemical energy by a process called “oxidative phosphorylation”. Thus, the elaborate structure of a mitochondrion is very important for the functioning of the organelle.