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What are Mitochondria

Mitochondria is a double membrane-bound cell organelle present in the cytoplasm of all higher organisms. They produce a huge amount of energy in the form of ATP and thus called the ‘powerhouse of the cell’. The word ‘mitochondrion’ comes from the Greek word ‘mitos’, meaning ‘thread’ and ‘chondrion’, meaning ‘granule’ or ‘grain-like’.

Richard Altmann discovered mitochondria in 1890 and called them ‘bioblasts’. Carl Benda coined the term ‘mitochondrion’ in 1898.


Where are Mitochondria Located

They are found in the cytoplasm of nearly all plant and animal cells. Typically, there are about 2000 mitochondria per cell, making up 25% of the cell volume. Mitochondria are more abundantly found in the liver cell (up to 1600), muscle cell, sperm cell, and oocyte (more than 300,000), where energy is in high demand.


How Big are Mitochondria

The size and shape of mitochondria vary from one tissue to another based on the functions they perform and the environment in which they work. Most mitochondria have a diameter of approximately 0.5 to 1.0 µm and a length of about 7 µm.

What do Mitochondria Look Like

It is a ‘bean’ shaped organelle that is constantly in the state of division to form a network. These networks are always changing their shape and size based on the tissue or organ, where they function. Find the best maid service anchorage ak nearby.

What are their Parts

  1. Double Membrane: Outer and inner membrane consisting of proteins and phospholipid molecules
  2. Intermembrane Space: Space between the two membranes. It has the same composition as that of the cell’s cytoplasm
  3. Cristae: Formed by inward foldings of the inner membrane. Proteins known as F0F1-ATPases that produce the majority of ATP used by cells are found distributed throughout the cristae.
  4. Matrix: Space enclosed by the inner membrane. It contains a viscous fluid containing a mixture of enzymes and proteins along with ribosomes, inorganic ions, DNA, nucleotide cofactors, and organic molecules
  5. DNA: Genetic material of mitochondria

Functions of Mitochondria in Plant and Animal Cell

The two main functions of mitochondria are:  1) promoting the growth of new cells and in cell multiplication, and 2) serving as the ‘energy currency’ of the cell by synthesizing high-energy phosphate molecule – ATP

Other Important Functions:

  • Producing body heat by the accumulation of brown-fat
  • Controlling various cellular activities such as cell differentiation, cell signaling, cell movement, and also in the cell cycle.
  • Helping in the accumulation of calcium ions, iron-containing pigments such as ferritin, and phosphates such as osteoblasts of bone, within the cell
  • Building certain parts of blood and hormones like testosterone and estrogen


Q1. What simple sugar is broken down in the mitochondria?

Ans. Glucose and some other carbohydrates are the macromolecules made by plants during photosynthesis that are broken down in the mitochondria during cellular respiration.

Q2. How are human mitochondria inherited?

Ans. Human mitochondria usually are inherited exclusively from the mother during sexual reproduction.

Q3. Do bacteria have mitochondria?

Ans. Bacteria do not contain any membrane-bound organelles, including mitochondria.

Q4. Why do some cells have more mitochondria?

Ans. The number of mitochondria depends on the energy requirement of the cell. Some cells, such as muscle cells and cells of heart, kidney, and pancreas, need the energy to do mechanical work and thus have more mitochondria than other cells of the body.

Q5. What is the difference between mitochondria and chloroplast?

Ans. Mitochondria are an energy-producing organelle that helps oxygen-dependent organisms to perform cellular respiration. In contrast, the chloroplast is an energy-utilizing organelle that helps all green plants and blue-green algae to produce food by photosynthesis.

Q6. Do mitochondria have ribosomes?

Ans. Mitochondria have ribosomes that perform their own protein synthesis, specifically in the matrix.

Q7. How do mitochondria have their DNA?

Ans. Mitochondria preserved a small part of their own DNA from the time they were prokaryotes. During the time life originated, it is believed that mitochondria had independent existence where they used to multiply similar to bacteria.

Article was last reviewed on Wednesday, July 15, 2020

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