Mysterious Mitochondria

Hello readers! I read an interesting piece today on the Guardian about the consultation on babies with three people's DNA, a controversial technique that is currently banned but could prevent women from passing mitochondrial diseases on to their children. The reason that this technique is currently controversial is due to the fact that the procedure lead to babies with DNA from three people. Mitochondrial transfer has never been tried in humans and is prohibited in Britain due to the law that bans the placing of an egg or embryo into a woman if the DNA has been altered. However, scientists working on the technique states that it offers hope of preventing life-threatening diseases for which there were no cures. At the moment, about 1 in 200 children born in the UK have some form of mitochondrial disorder. This is, despite being a slow progress, a great step into the direction of preventing such diseases as the government announced last June that it intends to allow the procedure, although regulations must be finalized, debated and approved by Parliament before clinics can offer the treatment. It also leads to today's post piece, on...the title may allow for a guess...mitochondria!

  

What is it?

Mitochondria is an organelle found in  large numbers in most cells, where in them, the biochemical processes of respiration and energy production to occur. The cytoplasm of nearly all eukaryotic cells contain mitochondria and they are especially abundant in cells associated with active processes, for example, in flagellated protozoa or in mammalian sperm. This is because they are involved in energy production. Multicellular organisms probably could not exist without mitochondria. The inability to remove electrons from the system and the buildup of metabolic end products restrict the utility of anaerobic metabolism. Through oxidative phosphoryation mitochondria make efficient use of nutrient molecules. They are the reason that we need oxygen at all.

What is it made up of?

Here is a diagram below of the organelle:

In the structure of a mitochondrion, it has two membranes, unlike other organelles. The outer membrane covers the organelle and contains it and the inner membrane folds over many times, these folds known as cristae. This folding over increases the surface area inside the organelle which speeds up reactions. Many of the chemical reactions happen on the inner membrane of the mitochondria, therefore the maximum amount of 'work' happens in the organelle. The fluid inside the mitochondria is called the matrix. The matrix is filled with water and proteins, which are enzymes that speed up the generated energy in order for reactions to take place at a quicker amount of time. These proteins take food molecules and combine them with oxygen. The mitochondria are the only place in the cell where oxygen can be combined with food molecules. Once this occurs, the material can be digested. So, in more specific terms, the enzymes in the matrix break down carboydrates and sugars to produce adenosine triphosphate (ATP). ATP molecules store the chemical energy required by the cell to carry out its metabolic functions. Other functions of the mitochondria include controlling the cell cycle - signaling, differentiation, growth and death - and assisting with cellular aerobic respiration. A mitochondrion may also be involved in controlling the concentration of calcium within the cell.

Mitochondrion disease

Mitochondrial diseases result from failures of the mitochondria. As they are responsible for creating more than 90% of the energy needed by the body to sustain life and support growth, when they fail, less energy is generated within the cell. This causes cell injury and even cell death follow. If this process is repeated throughout the body, whole systems begin to fail, and the life of the person in whom this is happening is severely compromised. The disease primarily affects children, but adult onset is becoming more and more common.This diseases appear to cause the most damage to cells of the brain, heart, liver, skeletal muscles, kidney and the endocrine and respiratory systems. Symptoms may include loss of motor control, muscle weakness and pain, gastro-intestinal disorders and swallowing difficulties, poor growth, cardiac disease, liver disease, diabetes, respiratory complications, seizures, visual/hearing problems, lactic acidosis, developmental delays and susceptibility to infection.

Thanks for reading