Mitochondria are organelles found in cells that act as the powerhouse, producing energy through cellular respiration. They contain their own DNA and divide independently of the cell. Mitochondria likely originated from ancient bacteria that established an endosymbiotic relationship with early eukaryotic cells. They have a double membrane structure and folded inner membranes containing enzymes that facilitate ATP production. Mitochondrial diseases can affect multiple body systems and are often inherited from the mother due to maternal inheritance of mitochondrial DNA. Symptoms, diagnosis, and treatment depend on the specific disease but may involve supplements, exercise, and various therapies.

1. MITOCHONDRIA

2. DEFINITION :
• Mitochondria are unusual organelles. They act as the power plants of the cell,
are surrounded by two membranes, and have their own genome. They also
divide independently of the cell in which they reside, meaning mitochondrial
replication is not coupled to cell division. Some of these features
are holdovers from the ancient ancestors of mitochondria, which were likely
free-living prokaryotes.

3. STRUCTURE :

4. HISTORY :
• First observed by Richard altmann in 1890, established them as cell organelles and
called them "bioblasts” - An obsolete term for a microscopic particle
• In 1898, Carl Benda coined the term "mitochondria" from the Greek
• MITO - "thread" and CHONDRIAN - "granule"
CARL BENDA
RICHARD ALTMANN

5. ORIGIN OF MITOCHONDRIA :
• Mitochondria arose about 2 billion years ago when a bacterium fused with a
archael cell or established a symbiotic relationship with a primitive eukaryotic
cell
• The closest extant relatives of bacteria that gave rise to mitochondria are
rickettsia

6. There are two hypotheses about the origin of mitochondria:
ENDOSYMBIOSIS AUTOGENESIS
ORIGIN

7. ENDOSYMBIOSIS :
• The endosymbiotic hypothesis suggests that mitochondria were
originally prokaryotic cells
• Capable of implementing oxidative mechanisms that were not possible for
eukaryotic cells
• They became endosymbionts living inside the eukaryote
• Since mitochondria have many features in common with bacteria, the
endosymbiotic hypothesis is more widely accepted.

9. AUTOGENOUS :
• In the autogenous hypothesis, mitochondria were born by splitting off a
portion of DNA from the nucleus of the eukaryotic cell at the time of
divergence with the prokaryotes
• This DNA portion would have been enclosed by membranes, which could not
be crossed by proteins.

11. MORPHOLOGY :
• SIZE - 0.05 - 1.0 µm
• LENGTH - 1 - 10 µm long
• SHAPE - bean shaped
• NUMBER - Depends on type, size, function of the cell
eg: Liver cell contain an average of 1500 mitochondria

12. STRUCTURE :
• A mitochondrion contains outer and inner membranes composed of
phospholipid bilayers and proteins.
• The two membranes have different properties. Because of this
double-membraned organization
• Mitochondria have folding to increase surface area, which in turn
increases ATP (Adenosine Tri Phosphate) production. Mitochondria
stripped of their outer membrane are called mitoplasts.

13. there are five distinct parts to a mitochondrion:
• 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.

14. OUTER MITOCHONDRIAL MEMBRANE :
• The outer mitochondrial membrane is 60 to 75 angstroms (Å) thick
• It contains large numbers of integral membrane proteins called porins
• It has voltage-dependent anion channel (VDAC).
• The voltage dependent anion channel transports nucleotides, ions and
metabolites between the cytosol and the intermembrane space
• The outer membrane also contains enzymes involved in the elongation of
fatty acids, oxidation of epinephrine, and the degradation of tryptophan.

16. INTERMEMBRANE SPACE :
• It is also know as peri mitochondrial space
• It has high proton concentration
• The space between inner membrane and outer membrane is 70A
• Because the outer membrane is freely permeable to small molecules the
concentration of small molecules such as ions and sugars in the
intermembrane space is same as that of cytosol
• One protein that is localized to the intermembrane space in this way is
cytochrome c.

18. INNER MITOCHONDRIAL MEMBRANE :
• The inner mitochondrial membrane (IMM) which separates the mitochondrial
matrix from the intermembrane space.
• It is extensively folded and compartmentalized
• It is freely permeable only to O2, CO2 and H2O
• The inner mitochondrial membrane contains protein that performs redox
reaction In oxidative phosphorylation, ATP synthase, Transport proteins,
protein import machinery and mitochondria fusion and fission protein
• Several Antiport system exist allowing exchange of anions in the cytosol and
the mitochondria

20. CRISTAE :
• A crista (or cristae) is a fold in the inner membrane of a mitochondrion
• This providing a large amount of surface area for chemical reactions to occur
• This aids aerobic cellular respiration, because the mitochondrion requires
oxygen
• FUNCTION :
• The electron transport chain and chemiosmosis takes place on this membrane
as a part of cellular respiration to produce ATP

21. • F0 and F1 (oxysomes) particles are found in the innermost mitochondrial region and are attached
to the cristae and help in ATP production and oxidation.
• F1 particle is found in the matrix of mitochondria and is found attached to the cristae. It performs
a very major role in the formation of ATP molecules as it contains an enzyme called ATPase.

23. MATRIX OF MITOCHONDRIA :
• The mitochondrion consists of an outer membrane, an inner membrane, and
a gel-like material called the matrix
• It is where the citric acid cycle takes place
• It contains the mitochondrial DNA in a structure called a nucleoid
• It contains ribosomes that produce proteins used by the mitochondrion
• It contains granules of ions that appear to be involved in the ionic balance of
the mitochondrion

25. FUNCTION :
• Apoptosis (programmed cell death): Apoptosis is a natural process in which the
cells die. Mitochondria help decide which cells should die.
• Storing calcium: Mitochondria hold the calcium ions and release them when
needed.
• They use the oxygen that we inhale and convert the nutrients of food into
energy
• Mitochondria are thought to play crucial roles in the maintenance of
pluripotency, differentiation, and reprogramming of induced pluripotent stem
cells.

26. MITOCHONDRIAL DNA :
• Small, double stranded, covalently closed , circular molecule
• Occur in multiple copies
• It has 16569 bp
• Most usually remains attached to inner mitochondrial membrane
• Stores biological info required for growth and multiplication of mitochondria

27. • Encode RNA s and protein that are essential for mitochondrial function
• It codes 2r RNAs , 22 t RNAs and 13 mitochondrial membrane proteins
• Can undergo replication and duplication
• Not absolutely autonomous depends on nuclear DNA

29. INHERITANCE OF MT DNA :
• Mitochondrial DNA is inherited maternally in most animals
• Fathers only give genes to their children but mothers give both genes and
cytoplasm through their egg cell
• Since mitochondria are in the cytoplasm and reproduce themselves they only are
inherited from mothers
• Hence this pattern of mt DNA inheritance is well known as “maternal inheritance”

30. MITOCHONDRIAL DISEASES :
• Mitochondrial diseases are chronic (long-term), genetic, often inherited
disorders that occur when mitochondria fail to produce enough energy for
the body to function properly
• Mitochondrial diseases can affect almost any part of the body, including the
cells of the brain, nerves, muscles, kidneys, heart, liver, eyes, ears or pancreas

31. Many conditions can lead to secondary mitochondrial dysfunction and affect
other diseases, including:
• Alzheimer’s disease.
• Muscular dystrophy.
• Lou Gehrig’s disease.
• Diabetes.
• Cancer.

32. WHAT CAUSES MITOCHONDRIAL DISEASES:
• Autosomal recessive inheritance: This child receives one mutated copy of a
gene from each parent. There is a 25% chance that each child in the family will
inherit a mitochondrial disease.
• Autosomal dominant inheritance: This child receives one mutated copy of a
gene from either parent. There is a 50% chance that each child in the family
will inherit a mitochondrial disease.

33. • Mitochondrial inheritance: In this unique type of inheritance, the mitochondria
contain their own DNA. Only mitochondrial disorders caused by mutations in
the mitochondrial DNA are exclusively inherited from mothers. If this is the
way a mitochondrial disease was inherited, there is a 100% chance that each
child in the family will inherit a mitochondrial disease
• Random mutations: Sometimes genes develop a mutation of their own that is
not inherited from a parent.

34. SYMPTOMS OF MITOCHONDRIAL DISEASES?
Symptoms of mitochondrial diseases can include:
• Poor growth
• Muscle weakness, muscle pain, low muscle tone, exercise intolerance.
• Vision and/or hearing problems.
• Learning disabilities, delays in development.
• Autism spectrum disorder.
• Heart, liver or kidney diseases.

35. • Gastrointestinal disorders, swallowing difficulties, diarrhea or constipation,
unexplained vomiting, cramping, reflux.
• Diabetes.
• Increased risk of infection.
• Neurological problems, seizures, migraines, strokes.
• Movement disorders.
• Thyroid problems.
• Respiratory (breathing) problems.
• Lactic acidosis (a buildup of lactate).
• Dementia

36. DIAGNOSIS OF MITOCHONDRIAL DISEASES:
Diagnosis starts with a series of examinations and tests that may include:
• A review of a patient’s family history.
• A complete physical examination.
• A neurological examination.
• A metabolic examination that includes blood and urine tests, and, if needed, a
cerebral spinal fluid test (spinal tap).

37. Other tests, depending on the patient’s symptoms and the areas of the body that
are affected, might include:
• Magnetic resonance imaging (MRI) or spectroscopy (MRS) for neurological
symptoms.
• Retinal exam or electroretinogram (ERG) for vision symptoms.
• Electrocardiogram (EKG) or echocardiogram for symptoms of heart disease.
• Audiogram or auditory-brainstem evoked responses (ABER) for hearing
symptoms.
• Blood test to detect thyroid dysfunction if the patient has thyroid problems.
• Blood test to perform genetic DNA testing.

38. TREATMENT :
• Vitamins and supplements, including Coenzyme Q10; B complex vitamins,
especially thiamine (B1) and riboflavin (B2); Alpha lipoic acid; L-carnitine
(Carnitor) ; Creatine; and L-Arginine.
• Exercises, including both endurance exercises and resistance/strength training.
These are done to increase muscle size and strength. Endurance exercises
include walking, running, swimming, dancing, cycling and others.
Resistance/strength training include exercises such as sit-ups, arm curls, knee
extensions, weight lifting
• Other treatments. These may include speech therapy, physical therapy,
respiratory therapy and occupational therapy.