Australasian Science: Australia's authority on science since 1938

Power Failures in Our Cells

mitochondria

In this fluorescent image of a cell, the mitochondrial network is labelled red and the DNA stained green. The bulk of the green staining is in the nucleus but you can see the green spots throughout the mitochondrial network, which represent mitochondrial nucleoids. These are thought to contain multiple mtDNA molecules plus much of the protein machinery needed for mtDNA replication and expression. Credit: Dr Ann Frazier

By David Thorburn

Severe defects in mitochondrial function affect at least one in every 5000 births, but mitochondrial disorders can reveal themselves at any age through a wide range of symptoms and as contributing factors to conditions as disparate as diabetes and Parkinson’s disease.

The full text of this article can be purchased from Informit.

Anyone watching their waistline or thinking about athletic performance knows that dietary intake and energy expenditure go hand-in-hand. Fewer people appreciate that even at rest we need to constantly generate about 100 kCal of energy per hour. In electrical terms that is equivalent to about 100 W, the same amount used by a bright light globe.

We need this energy to allow our neurons to send messages, our heart to pump and our other organs to perform their roles. To do this we must be able to efficiently convert fuels such as fats, sugars and proteins into a small molecule called ATP, which is our chemical energy store.

Most of the ATP needed for cellular function and survival is generated in power plants within our cells called mitochondria. Each day we generate and consume about 65 kg of ATP, of which our hearts use about 6 kg and our brains about 12 kg.

Our development, growth and survival are thus heavily reliant on our mitochondrial power plants, but not everyone’s mitochondria work well enough. Severe defects in mitochondrial function are the most common group of inherited metabolic disorders, affecting at least one in every 5000 births. That means that at least 60 children born each year in Australia will develop a severe mitochondrial disease during their lifetime.

At the mildest end, the symptoms may only be exercise intolerance....

The full text of this article can be purchased from Informit.