Source: University of Virginia
Date Published: October 16, 2014
Mitochondria, often referred to as the
“powerhouse” organelles, are vital to the survival of nearly all
eukaryotic cells, found in both plants and animals. They turn the energy from the food we eat
into ATP (adenosine triphosphate,) a molecule used to perform
cellular functions. Little is known about the exact details of how
these organelles originated and how they evolved to where they are today. The most common theory is endosymbiotic
theory. This says that around 1.5 billion years ago, bacteria
were ingested by prokaryotic cells, creating a symbiotic relationship
where both individuals benefited. The bacteria got protection and the cell gained
ATP energy. As time went on, the bacteria and cell became
increasingly dependent upon one another, eventually evolving into the
mitochondria and eukaryotic cells of today.
A recent study from the University of
Virginia suggests that the first relationships between the mitochondrial bacteria
and its host cell were likely parasitic, instead of mutualistic as many people currently believe. From
analyzing the DNA of mitochondrial relatives, scientists predict
that early bacteria probably stole ATP energy from the cell at first,
only becoming useful to its host much later on“by
switching the direction of the ATP transport” (Science Daily).
This
article relates to our curriculum because we are currently learning
about the functions and roles that each organelle plays in the cell.
For example, mitochondria turn the stored energy from the food we
eat into ATP energy.
Furthermore, it ties into our studies of
the differences between a prokaryotic and eukaryotic cell, and how scientists are able to study and form theories about how life evolves.
What exactly does "switching the direction of the ATP transport" mean? Does it mean that after mitochondrial bacteria stole ATP energy from the cell, the cell took back the ATP energy from the bacteria? So was it like a continuous 'tug of war'?
ReplyDeleteI interpreted "switching the direction of ATP transport" to mean that after a long time, the mitochondrial bacteria began to work together with the cell, instead of simply stealing the ATP away. The relationship evolved from being parasitic to mutualistic over thousands of years.
ReplyDelete"The replacement of plastid/parasite ATP/ADP translocase by mitochondrial ATP/ADP translocase occurred subsequently, resulting in a reverse flow of ATP between mitochondrion and its host." This is a quote from the publication in the original science journal. I think this is what "switching the direction of ATP transport" was referring to.
http://www.plosone.org/article/info%3Adoi%2F10.1371%2Fjournal.pone.0110685
How and why did the bacteria stop parasitizing the cell and started benefiting it?
ReplyDelete