MITOCHONDRIA

MADE BY:

SHREYAANS M. N

AHATA

SUDARSHAN A. SOMANI

INDEX• WHAT IS MITOCHONDRIA?• MICROSCOPIC IMAGE OF MITOCHONDRION• LOCATION OF MITOCHONDRIA IN CELL• FUNCTIONS OF MITOCHONDRIA• Krebs cycle or citric acid cycle• Why is mitochondria referred as the “powerhouses of cell”• MITOCHONDRIA As The Site Of Cellular Respiration• STRUCTURE Of A MITOCHONDRION-

MATRIX,CRISTAE,DNA,INNER AND OUTER MEMBRANE, RIBOSOMES

• The presence of mitochondria• MITOCHONRIAL Diseases • THANKS!!!!!!!!!!!!!!

WHAT ARE MITOCHONDRIA?

• The mitochondrion is an organelle that carries out the process of aerobic respiration. An organelle is a membrane-bound structure in the cell that performs a specific function. Aerobic respiration is the breakdown of simple food molecules like glucose in the presence of oxygen.

MICROSCOPIC IMAGE OF MITOCHONDRION

LOCATION OF MITOCHONDRIA IN CELL

• There are usually multiple mitochondria found in one cell, depending upon the function of that type of cell. Mitochondria are located in the cytoplasm of cells along with other organelles of the cell.

LOCATION OF MITOCHONDRIA IN CELL

FUNCTIONS OF MITOCHONDRIA

• The most prominent roles of mitochondria are to produce the energy currency of the cell, ATP through respiration, and to regulate cellular metabolism. The central set of reactions involved in ATP production are collectively known as the citric acid cycle, or the Krebs cycle.

Krebs cycle or citric acid cycle

• The citric acid cycle – also known as the tricarboxylic acid (TCA) cycle or the Krebs cycle – is a series of chemical reactions used by all aerobic organisms to generate energy through the oxidation of acetate derived from carbohydrates, fats and proteins into carbon dioxide and chemical energy in the form of adenosine triphosphate (ATP).

Why is mitochondria refered as the “powerhouses of cell”

• They produce ATPs known as the energy currency of the cell.

• The ADPs (Adenosine Diphosphate) produced in the cell get combined with one more atom of phosphorous to get converted into ATP.

• The mitochondria supply ATP to the cell whenever needed.

MITOCHONDRIA As The Site Of Cellular Respiration

• Cellular respiration is the process of oxidizing food molecules, like glucose, to carbon dioxide and water.

• C6H12O6 + 6O2 + 6H2O → 12H2O + 6 CO2

• The energy released is trapped in the form of ATP for use by all the energy-consuming activities of the cell.

• The process occurs in two phases:glycolysis, the breakdown of glucose to pyruvic acid

• the complete oxidation of pyruvic acid to carbon dioxide and water

STRUCTURE Of A MITOCHONDRION

• THE PARTS OF MITOCHONDRION ARE:-MATRIXCRISTAE

DNAINNER AND OUTER MEMBRANE

RIBOSOMES

MATRIX

• The mitochondrial matrix contains a highly-concentrated mixture of hundreds of enzymes. These include most of the enzymes that participate in the TCA Cycle - which is also known as the "Krebs Cycle“. The only enzyme involved in the TCA Cycle that is not free in the mitochondrial matrix is succinate dehydrogenase - which is located on the inner-surface of the inner mitochondrial membrane.It contains proteinacious liquid.

CRISTAE

• Mitochondrial cristae are folds of the mitochondrial inner membrane that provide an increase in the surface area. This allows a greater space for processes that happen across this membrane. These processes are the electron transport chain and chemiosmosis, which help produce ATP in the final steps of cellular respiration. the folds are studded with small round bodies known as F1 particles or oxysomes.

DNA

• Mitochondrial DNA is the DNA located in mitochondria, cellular organelles within eukaryotic cells that convert chemical energy from food into a form that cells can use, adenosine triphosphate (ATP). Mitochondrial DNA is only a small portion of the DNA in a eukaryotic cell; most of the DNA can be found in the cell nucleus and, in plants, in the chloroplast

Replication & Inheritance in MITOCHONDRIA

• Mitochondria divide by binary fission, similar to bacterial cell division.

• The regulation of this division differs between eukaryotes. In many single-celled eukaryotes, their growth and division is linked to the cell cycle. For example, a single mitochondrion may divide synchronously with the nucleus.

• This division and segregation process must be tightly controlled so that each daughter cell receives at least one mitochondrion.

• In other eukaryotes (in mammals for example), mitochondria may replicate their DNA and divide mainly in response to the energy needs of the cell, rather than in phase with the cell cycle.

• When the energy needs of a cell are high, mitochondria grow and divide. When the energy use is low, mitochondria are destroyed or become inactive. In such examples, and in contrast to the situation in many single celled eukaryotes, mitochondria are apparently randomly distributed to the daughter cells during the division of the cytoplasm.

• Understanding of mitochondrial dynamics, which is described as the balance between mitochondrial fusion and fission, has revealed that functional and structural alterations in mitochondrial morphology are important factors in pathologies associated with several disease conditions.

Inner membrane

• The inner mitochondrial membrane contains proteins with five types of functions:

(1) Those that perform the redox reactions of oxidative phosphorylation.

(2) ATP synthesis, which generates ATP in the matrix.

(3) Specific transport proteins that regulate metabolite passage into and out of the matrix.

(4) It is a protein import machinery.

Outer membrane

• The outer mitochondrial membrane, which encloses the entire organelle, is 60 to 75 angstroms (Å) thick.

• It has a protein-to-phospholipid ratio similar to that of the eukaryotic plasma membrane (about 1:1 by weight). It contains large numbers of integral membrane proteins called porins.

• These porins form channels that allow molecules of 5000 daltons or less in molecular weight to freely diffuse from one side of the membrane to the other.

RIBOSOMES

• The mitochondrial ribosome is responsible for the biosynthesis of protein components crucial to the generation of ATP in the eukaryotic cell.

• Mitoribosomes synthesize crucial cellular components needed to generate about 90% of the ATP required by a eukaryotic cell.

STRUCTURE Of A MITOCHONDRION

The presence of mitochondria

• Mitochondria is more in animal cells then plant cells because animals require more energy for their metabolic activities.

• But the mitochondria is absent in RBCs.• Mitochondria is also absent in bacteria.

MITOCHONRIAL Diseases• Damage and subsequent dysfunction in mitochondria is

an important factor in a range of human diseases due to their influence in cell metabolism.

• Mitochondrial disorders often present themselves as neurological disorders, including autism. They can also manifest as myopathy, diabetes, multiple endocrinopathy, and a variety of other systemic disorders.

• Diseases caused by mutation in the mt-DNA include Kearns-Sayre syndrome, MELAS syndrome and Leber's hereditary optic neuropathy.

• In the vast majority of cases, these diseases are transmitted by a female to her children, as the zygote derives its mitochondria and hence its mt-DNA from the ovum.

• Diseases such as Kearns-Sayre syndrome, Pearson's syndrome, and progressive external ophthalmoplegia are thought to be due to large-scale mt-DNA rearrangements, whereas other diseases such as MELAS syndrome, Leber's hereditary optic neuropathy, myoclonic epilepsy with ragged red fibers (MERRF), and others are due to point mutations in mt-DNA.

Size Of A MITOCHONDRION

• A mitochondrion is typically long and slender, but it can appear bean-shaped or oval-shaped under the electron microscope. Ranging in size from 0.5 micrometer (0.00005 in) to 1 micrometer (0.0001 in) in length, a mitochondrion has a double membrane that forms a sac within a sac.