Mitochondrial function

Mitochondria function to produce energy in the form of ATP. The Krebs cycle occurs inside the mitochondria. If a cell is not making energy, it will not be able to carry out any of its other functions. By removing mitochondria from a cell, you essentially kill the cell.

Mitochondria are the "powerhouse" organelles of the cell. In eukaryotic cells, mitochondria produce ATP, which serves as a main source of cellular energy. They function via oxidative phosphorylation, and the Krebs cycle occurs inside the matrix of the mitochondrion. The resulting NADH, produced in glycolysis and then in the Krebs cycle, is shuttled into the intermembrane space and then into the matrix, where it is oxidized by the electron transport chain.

The Krebs Cycle takes place in mitochondria.

The mitochondrion, the powerhouse of the cell, is responsible for cellular respiration. This process converts chemical energy stored in glucose into ATP, the molecule that powers most reactions in our body.

The Krebs cycle (also known as the citric acid cycle) is a series of reactions in the mitochondria where acetyl-CoA (a two-carbon compound derived from pyruvate) is oxidized to CO2 and synthesizes a 5-carbon compound called oxaloacetate. The cycle is named after Hans Krebs, who identified it in 1937.

Being an earth scientist and the father of two budding geologists, I was interested to learn that mitochondria are considered by some biologists to be the result of ancient bacteria that were engulfed and enslaved by other cells. Mitochondria produce energy for the cell, generating ATP via Krebs cycle. And yet they have their own DNA, and reproduce independently from the host cell.

This is called symbiosis — when two different species live together in a mutually beneficial relationship. Symbiosis is a pretty common phenomenon, so it's not surprising that we find it on the cellular level as well.

For example, most plants have a symbiotic relationship with fungi (mycorrhizae). The plant supplies the fungus with sugar; the fungus provides water and minerals to the plant. Many ancient plants have evolved into trees, which have little need for fungal exchange; but modern plants like corn or tomatoes benefit greatly from mycorrhizal association. Among animals, there are many examples of symbiotic relationships: cleaner fish feeding on parasites; hermit crabs occupying snail shells; clownfish inhabiting poisonous anemones. In each case, both participants benefit from the arrangement.

Mitochondria are the energy generators of our cells. All of the chemical reactions that provide us with energy take place in these organelles. Each mitochondrion is a dynamic, round-shaped structure surrounded by two membranes - an outer membrane and an inner membrane. The intermembrane space is the area between the two membranes, and the matrix is the enclosed space within the inner membrane. The outer membrane encloses all of the organelle's contents, while the inner membrane has many folds called cristae that greatly increase its surface area.

Biological molecules in the primitive atmosphere.

Theoretically, all the organic molecules required for life can be made under conditions that could have existed on the early Earth. Most of these reactions take place in the presence of water, carbon dioxide and nitrogen but require ultraviolet light or heat to provide the energy needed to break the bonds of starting materials and form new compounds.

The process is called prebiotic synthesis.

These organic molecules are incorporated into larger structures as they are synthesized. Microscopic organic-walled structures called coacervates or protobionts have been produced in the laboratory under prebiotic conditions by aggregation of amino acids and other biological monomers such as nucleotides. The coacervates formed are microscopic droplets that contain all the necessary macromolecules for early life: proteins, nucleic acids, carbohydrates and lipids, enclosed in a lipid membrane – in other words, a cell membrane.