This document discusses mitochondria, double membrane-bound organelles found in eukaryotic cells that are often described as the "powerhouses" of cells. It provides details on the structure of mitochondria including their outer membrane, inner membrane, intermembrane space, cristae, and matrix. The key functions of mitochondria are also summarized as generating ATP through oxidative phosphorylation, containing their own DNA, and performing various metabolic reactions and other roles in processes like thermogenesis and apoptosis.

1. Mitochondria
Angel Anna Lal
Msc Biotechnology
1st year.

2. INTRODUCTION
 The mitochondrion (plural mitochond
ria) .[greek];
 It is a double membrane-
bound organelle found eukaryotic
cells.
 mito= thread
chondrion = granule like
 Found in cytoplasm of the cell.
 Power house of cell.
 First observed by Richard Altman
(1894).
 Term mitochondria was coined by
Carl Benda (1898).

4. SIZE: Mitochondria range from 0.5 to 1.0 μm in diameter.
SHAPE: normally Sausage shaped,
 In fibroblasts-elongated and thread like
NUMBER: Depends on type size and functional state of
cell.
Eg: An average liver cells contain around 1500
mitochondria.
LOCATION: Cells with high enrgy requirements;
Eg:Sperm tail, Muscle, Flagella

5. In most animals ,
oozyte mitochondria [maternal] are the only
mitochondria that is inherited
.
Spermatazoa mitochondria [paternal] also
enters oocyte during fetilization,but destroyed
during early embryonic development.
Mechanism not yet ellucidated.

6. 1. Outer Membrane
2. Intermembrane Space
3. Inner Membrane
4. Cristae
5. Matrix

8. OUTER MEMBRANE
 Simple phospholipid bilayer.
 It encloses the mitochondrion.
 Containing protein structures called porins.
 Ions, nutrient molecules, ATP, ADP, etc. can pass through the outer membrane
with ease.
INNER MEMBRANE
 Is freely permeable only to oxygen, carbon dioxide, and water.
 Contains complexes of the ETC, the ATP synthase complex, and transport
proteins.
 Presence of sophisticated ion transporters exist.
 Several antiport systems exist, allowing exchange of anions between
the cytosol and the mitochondrial matrix.
 It is devoid of cholesterol and rich in phospholipid & cardiolipin.

9. Intermembrane space
Matrix

10. the space between inner membrane and outer membrane {O
cavity}
It has high proton concentration.
The space between inner and outer memebrane is approx
70 angstrom.
Conc is same as that of the cytosol.
CRISTAE
Are folds of inner mitochondrial membrane.
Stalked particles or inner membrane spheres: cristae is
covered with this inner membrane spheres called stalked
particles or knobs or heads.
They contain protein called F1 portion & F0 portion. For
ATP synthesis and ATO oxidation.

11. MITOCHONDRIAL MATRIX:
Gel like consistency
Dense ,homogenous
2/3rd of total protein of mitochondria
 Mitochondria have: - enzymes
-ribosomes
-DNA
-mRNA
-granules
-fibrils
-tubules.
Major enzymes include enzymes involved in:
-Synthesis of nucleic acid and proteins
-Fatty acid oxidation
-TCA CYCLE (except succinate dehydrogenase)

12. MITOCHONDRIAL DNA (mt DNA):
Double stranded, covalently closed,
circular molecule.
Occurs in multiple copies.
Most usually remains attached to inner
mitochondrial membrane.
Stores biological info required for growth
and multiplication of mitochondria.
Can undergo replication and duplication.
 Human mt DNA 2 rRNA
22 tRNA
Not absolutely autonomous depends on
nuclear DNA.[partially autonomous]

13. FUNCTIONS OF MITOCHONDRIA:
Energy transducer of the cell- synthesis of ATP
Kreb’s cycle in matrix
ETC system
Phosphorylating system- ATPase
Extra mitochondrial inheritance:
mtDNA contains plasma genes (extra chromosomal genes)
Transmitted from mother to the offspring
Synthesis of mtDNA, RNA, protein.
 Bring about gene expression through gene duplication
transcription and translation.
Synthesis 13 different polypeptides in human.

14. Site of several metabolic reactions
Outer membrane
Oxidation of epinephrine
Degradation of tryptophan
Elongation of fattyacid
Inner membrane : oxidative phosphorylation
 Matrix
Kreb’s cycle
Beta oxidation
Detoxification of ammonia in urea cycle
Storage of calcium ions

15. OTHER FUNCTIONS:
 production of heat ( non shivering thermogenesis).
[ The unharnessed potential energy of proton-electrochemical
gradient produced during ETC is released as heat.]
Role in apoptosis ( programmed cell death).
Synthesis of estrogen and testosterone.
Role in neurotransmitter metabolism.
Role on cholesterol metabolism.