Question

How does ATP leave the mitochondria?

Answer 1

A mitochondrion is present in most eukaryotes and it is a double membrane-bound organelle. Most of the cell's energy is generated by mitochondria in the form of ATP (adenosine triphosphate) The discovery of Mitochondria was made by Kolliker in the year 1880 in the voluntary muscles of insects. A mitochondrion is also named as the "powerhouse of the cell" due to its generation of a large amount of energy in the form of ATP. It is found out that Mitochondria may have a number of different shapes other than the usual sausage shape.

Complete solution:
The outer and inner membrane of mitochondria are composed of phospholipid bilayers and proteins. Both the membranes have different properties.
The structure of mitochondria is divided into five different parts:
1. The outer mitochondrial membrane,
2. The intermembrane space (the space between the outer and inner membranes),
3. The inner mitochondrial membrane,
4. The cristae space (formed by infoldings of the inner membrane), and
5. The matrix (space within the inner membrane), which is a fluid.
The inner Mitochondrial membrane has folding to increase surface area, which is helpful in increasing ATP (Adenosine Triphosphate) production.
The main transport protein which transports the ATP (Adenosine triphosphate) is called the mitochondrial ADP/ATP carrier. The transport of ATP out of the cell is a vital process to keep us alive.
Examples of processes which depend on ATP: Muscle contraction, nerve impulses, DNA replication and protein synthesis, these are only few which are described here.
The amount of ATP in our body is very little so we need to remake it from the product ADP (adenosine diphosphate) and phosphate using an enzyme complex, called ATP synthase, which is located in the mitochondrial membrane.
Each and every molecule of ATP is recycled around 1300 times a day in our body. The ADP molecule has to reach to the enzyme and when the product which is ATP is formed it has to come out of the mitochondria to provide fuel to the cell, so in this process mitochondrial ADP/ATP carrier works by transporting ADP inside and ATP outside of mitochondria.

Note:
Other than The ADP/ATP carrier there are various proteins which are involved in the transport of substances in and out of mitochondria. There are various diseases associated with the dysfunction of these carrier proteins, now for the first time scientists are able to understand how mutations affect the function of these carrier proteins.