Mitochondria and Peroxisomes Overview

Mitochondria are cellular organelles responsible for generating most of the cell's energy via the breakdown of carbohydrates and fats.

Mitochondria are surrounded by two membranes: an outer membrane and an inner membrane. The space between these membranes is called the intermembrane space.

The inner membrane of mitochondria is folded into cristae, which increase the surface area for energy production.

The fluid-filled space within the inner membrane is called the matrix. This compartment houses the mitochondrial DNA and enzymes involved in energy production.

Mitochondrial DNA (mtDNA) encodes for some of the proteins and RNA molecules needed for mitochondrial function.

Most mitochondrial proteins are synthesized in the cytoplasm and then imported into the organelle. However, some are encoded by mtDNA and synthesized within the mitochondria.

Mitochondria are dynamic organelles that can fuse with each other (fusion) or divide (fission) to maintain a healthy population within the cell.

Oxidative phosphorylation is the process by which mitochondria convert nutrients into ATP, the cell's main energy currency.

Mitochondrial diseases are a group of disorders that result from dysfunction of mitochondria, the powerhouses of cells. They are caused by mutations in either nuclear or mitochondrial DNA, affecting energy production.

Mitochondrial diseases have no cure, but treatments can help manage symptoms. These include therapies to increase energy production, reduce oxidative stress, and address specific organ system issues.

Mitochondrial diseases are often inherited, meaning they can be passed from parent to child. This can occur through either the mother's egg or the father's sperm.

Preimplantation Genetic Diagnosis (PGD) helps identify embryos carrying the mutated mitochondrial DNA before implantation, allowing for genetic screening of embryos before transfer.

Mitochondrial Replacement Techniques (MRT) involve manipulating or replacing the mitochondria in an egg or embryo with healthy mitochondria from a donor.

Mitochondrial proteins can be synthesized either within the mitochondria or in the cytoplasm. The majority of mitochondrial proteins are encoded by nuclear DNA and synthesized in the cytoplasm. These proteins are then imported into the mitochondria through specific pathways.

Mitochondrial protein import is a complex process involving multiple steps and protein complexes. Firstly, leader sequences on the proteins target them to the mitochondria. Then, these proteins are translocated through the mitochondrial membranes, with specific protein complexes aiding in this process.

The inner mitochondrial membrane has an electrochemical potential that aids in protein import into the matrix. There are special protein complexes that guide the movement of proteins through the membranes.

A short amino acid sequence at the N-terminus of a protein that targets it to mitochondria.

A protein complex in the outer mitochondrial membrane that helps proteins cross.

A protein complex in the inner mitochondrial membrane that helps proteins cross, specifically for proteins with multiple transmembrane domains.

A protein complex in the inner mitochondrial membrane that imports proteins synthesized within the mitochondria.

Chaperone proteins that bind to mitochondrial proteins in the intermembrane space, guiding them to their final destination.

A protein complex in the outer mitochondrial membrane that helps insert barrel proteins into the membrane.

A phospholipid found in the mitochondrial inner membrane, important for membrane structure and function.

The process by which lipids are synthesized in the ER and then transported to mitochondria.