MITOCH ONDRIA BIOLOGY PROJECT By V.V.Ram Sharan IX Topaz

MITOCHONDRIA WE ARE GOING TO SEE ABOUT THE FUNCTIONS AND STRUCTURE OF

MITOCHONDRIA Mitochondria is a membrane-bound cell organelle which is located in the cytoplasm of the cell that is present in most eukaryotic cells. Mitochondria range from 0.5 to 1.0 μ m in diameter. It is also known as the ‘powerhouse of the cell’ as it produces energy for the cell. It is semi-autonomous (self-replicating) because it has its own DNA,so, it can make things like proteins that they require. There is a theory about the origin of Mitochondria called ‘SYMBIOTIC THEORY’. We will be seeing it later here. 3

A SIMPLE PICTURE OF MITOCHONDRIA 4 MITOCHONDRIA IN A CELL

ETYMOLOGY The word mitochondrion comes from the Greek, mitos, i.e. "thread", and chondrion, i.e. "granule" or "grain-like". Discovery Mitochondria were first discovered in 1886 by Richard Altman, who thought they were parasites inside the cell. Scientists soon noticed that mitochondria were found in every cell, but were most dense in muscle cells. 5

ORIGIN There are two hypotheses about the origin of mitochondria: endosymbiotic and autogenous. The endosymbiotic hypothesis suggests mitochondria were originally prokaryotic cells, capable of implementing oxidative mechanisms that were not possible for eukaryotic cells; they became endosymbionts living inside the eukaryote. 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. Since mitochondria have many features in common with bacteria, the most accredited theory at present is endosymbiosis. 6

ORIGIN A picture showing the origin of eukaryotic cells with mitochondria through endosymbiotic theory. 7

STRUCTURE Mitochondria has a double-layered membrane. These membranes are made of phospholipid, bilayers and proteins. The outer membrane is very porous. While the inner membrane is deeply folded. These folds are called cisternae which create a large surface area for energy generating chemical reactions. It has its own DNA and ribosomes on the folds. 8

A PICTURE SHOWING STRUCTURE OF A MITOCHONDRIA 9

FUNCTION The energy required for various chemical activities needed for life is released by Mitochondria in the form of ATP (Adenosine Triphosphate). ATP is the ‘energy currency of the cell’. The body uses the ATP stored for forming new chemical compounds and mechanical work of the body. It has its own DNA and ribosome which distributes the proteins required for itself. ATP is produced through ‘Cellular Respiration’. It also regulates the cellular metabolism. It also synthesizes steroid. 10

HERE WE ARE GOING TO SEE ABOUT THE SMALL SPECIFICATIONS OF EACH. 1 glucose = 38 ATP 1 NADH ₂ = 3 ATP 1 FADH ₂ = 2 ATP NADH ₂ - Nicotinamide-Adenine Dinucleotide FADH ₂ - Flavin-Adenine Dinucleotide 11

PRODUCTION OF ATP 1.Intake of Food. 2.Digestion of food in taken. 3.Breaking down of food molecules (complex to simple). 4.Carbohydrate glucose. 5.Protein amino acids. 6.Fat fatty acids. 7.The result will be Glucose. 8.Then assimilation takes place. 9.The absorbed glucose will be sent to cell (cytoplasm). 10.Glycolysis (lysis means shrinking) takes place. 11.In this process glucose is converted into pyruvic acid, and during this process some amount of ATP is released but this is not enough. 12

Next, oxidation of pyruvic acid takes place. Here pyruvic acid released is oxidized which gives out Acetyl COa and some NADH ₂ with some ATP. The Acetyl COa should be converted into NADH ₂ and FADH ₂. This takes place in the process of Krebs Cycle. The released NADH ₂ and FADH ₂ should be converted to ATP in order to utilize it. It is done in the process of ETC (Electron Transport Chain). These processes take place only in Aerobic respiration. In absence of oxygen, fermentation takes place, so, only less amount of ATP or energy is released. 13 Acetyl COa NADH ₂ FADH ₂ ATP NADH ₂ ATP FADH ₂ NADH ₂ FADH ₂ NADH ₂

BIBLIOGRAPHY for images My 9 th grade Biology Classwork 9 th grade NCERT Science book 14

THANK YOU ! 15