Mitochondrial

 Mitochondrion is the site of the Krebs cycle and the electron transport chain in eukaryotic organisms. It has a variable diameter from 0.5 to 1 micrometre thus can be easily seen under a light microscope. It is surrounded by two phospholipid membranes: the outer and inner membrane. The inner membrane is folded inwards to form cristae and it is the location where electron transport chain occur.  On the other hand, the outer membrane is the envelope that holds all the organelles and it is relatively permeable to small molecules. The internal mitochondrial compartment is called the matrix where link reaction and Krebs cycle occur. As a result of oxidative phosphorylation, ATP is synthesised in the latter by the activity of ATP synthase on the cristae. The advantage that this has over glycolysis is that it reaps 15 times more ATP for all energy-requiring reactions of the cell, both inside and outside the mitochondria. Moreover, it has its own DNA which is linear and also contains 70s ribosomes. In addition, it is also beneficial since as a result of cell damage, it is the one who signals the process of apoptosis (cell death) by releasing mitochondrial protein into the cytoplasm.

Berg J.M, Tymoczko J.L, Stryer (2012) Biochemistry, seventh Edition, New York: WH Freema.. pg 543

Alberts, Johnson, Lewis, Raff, Roberts, Walter (2008) Molecular Biology of the cell, Fifth edition, pg 815

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