MITOCHONDRIA & NUCLEUS

A BRIEF PRESENTATION ON MITOCHONDRIA AND NUCLEUS
NOTE- FONTS MAY APPEAR WEIRD BCOZ THE FONTS I USED DO NOT APPEAR IN THIS PPT.

1. Kanav Bhanot Roll no . 5 Presentation on MITOCHONDRIA & NUCLEUS by

2. CONTENTS MITOCHONRIA What is Mitochondria? Structure Functions NUCLEUS What is Nucleus? Structure Functions Summary BIBLIOGRAPHY

3. MITOCHONDRIA Powerhouse of the Cell The mitochondrion (plural mitochondria) are called the “powerhouses” of the cell. Without them cells would be unable to extract enough energy from the nutrients and essentially all cellular functions would cease.

4. What is mitochondria ? The term "mitochondria" itself was coined by Carl Benda in 1898. The word mitochondrion comes from the Greek word mitos i.e. " thread“ and   chondrion i.e. "granule ". The mitochondrion (plural mitochondria) is a membrane-bound organelle found in most eukaryotic cells. Mitochondria range from 0.5 to 1.0 micrometer (μm) in diameter.

5. These structures are sometimes described as "cellular power plants" because they generate most of the cell's supply of adenosine triphosphate (ATP), used as a source of chemical energy. In addition to supplying cellular energy, mitochondria are involved in other tasks such as signalling, cellular differentiation, cell death, as well as the control of the cell cycle and cell growth . Mitochondria has its own DNA which is responsible for many enzymatic actions. Infact, it is the only organelle other than nucleus which has its own DNA.

6. Structure The outer mitochondrial membrane T he intermembrane space (the space between the outer and inner membranes ) The basic structure of mitochondria is composed of two lipid bilayer-protein membranes: an outer and an inner membrane. The two membranes have different properties. Because of this double-membraned organization, there are five distinct parts to a mitochondrion. They are:

7. The inner mitochondrial membrane The cristae space (formed by infolding of the inner membrane) The matrix (space within the inner membrane)

8. FUNCTIONS Production of Energy Mitochondria is called the “Power House” of the cell because it produces the energy required for cellular functions. The energy is produced during the oxidation of digested food particles like proteins, carbohydrates and lipids by the oxidative enzymes in cristae. During the oxidative process, water and CO 2 are produced with release of energy. The released energy is stored in mitochondria and used later for synthesis of ATP.

9. Synthesis OF ATP The components of respiratory chain in mitochondrion are responsible for the synthesis of ATP by utilizing the energy by oxidative phosphorylation. ATP molecules diffuse throughout the cell from mitochondrion. Whenever energy is needed for cellular activity the ATP molecules are broken down . ADDITIONAL FUNCTIONS Additional functions of mitochondria include: Apoptosis Storage of calcium Detoxification of ammonia in liver

10. NUCLEUS Brain of the Cell The nucleus is the “control centre” of the cell. It is the most important part of the cell, exerting a controlling influence on all cell activities .

11. What is Nucleus ? In cell biology, the nucleus (pl. nuclei; from Latin nucleus or nucleus, meaning kernel) is a membrane-enclosed organelle found in eukaryotic cells . It was discovered by A.V Leeuwenhoek for the first time. Scottish Botanist Robert Brown explained it in more detail in 1831. It coordinates the cell’s activities, which include growth, intermediary metabolism, protein synthesis and reproduction (cell division) by regulating gene expression.

12. Structure The nucleus is the largest cellular organelle in animals. In mammalian cells, the average diameter of the nucleus is approximately 6 micrometres (μm), which occupies about 10% of the total cell volume. Structure of Nucleus is made up of following: •Nuclear Membrane • Nuclear Pores • Chromatin • Nucleoplasm • Nucleolus

13. NUCLEAR MEMBRANE Nuclear Membrane separates the nucleus from the cytoplasm. It is mainly made up of protein and lipids . The nuclear envelope, otherwise known as nuclear membrane, consists of two cellular membranes, an inner and an outer membrane, arranged parallel to one another. The outer nuclear membrane is continuous with the membrane of the rough endoplasmic reticulum (RER), and is similarly studded with ribosomes. Nuclear Membrane

14. NUCLEAR PORES The nuclear pores are the gateways across which movement of RNAs and proteins takes place between the nucleus and cytoplasm in both direction. Each pore contains a donut-shaped, eightfold-symmetric ring-shaped structure at a position where the inner and outer membranes fuse . The nucleus of a typical mammalian cell will have about 3000 to 4000 pores throughout its envelope. Nuclear Pore

15. CHROMATIN Chromatin is a thread like material made up of large molecules of DNA. The DNA molecule is compactly packed with the help of specialised basic protein called histone. So chromatin is referred as DNA Histone Complex. The fundamental packing unit of chromatin is called Nucleosome. Just before cell division the chromatin condenses to form chromosome.

16. NUCLEOPLASM The nucleoplasm is a highly viscous liquid that surrounds the chromosomes and nucleoli. Similar to the cytoplasm of a cell . Many substances such as nucleotides (necessary for purposes such as the replication of DNA) and enzymes (which direct activities that take place in the nucleus) are dissolved in the nucleoplasm.

17. The nucleolus is a discrete densely stained structure found in the nucleus. A nucleolus is composed of Ribonucleic acid (RNA) and associated proteins. The nucleolus produces ribosomes, which move out of the nucleus and take positions on the rough endoplasmic reticulum where they are critical in protein synthesis. NUCLEOLUS NUCLEOLUS NUCLEAR PORE NUCLEAR MEMBRANE

18. FUNCTIONS It stores the cell hereditary material, or DNA. Site of DNA replication Site of DNA transcription to mRNA Ribosomal formation Control of all cell activities that include metabolism, protein synthesis, growth and reproduction (cell division).

19. SUMMARY From the aforesaid presentation we can conclude that Mitochondria and Nucleus play a vital role in the normal functioning of the cell and in case of any malfunctioning in any of the two organelles, all the essential functioning of the cell would cease and eventually the cell would die. So I believe that I have been able to convey the importance of Mitochondria & Nucleus in the normal functioning of the cell.

20. Bibliography The sources that enabled me to bring out this presentation to you all are : TEXTBOOK OF MEDICAL PHYSIOLOGY by GUYTON AND HALL www.wikipedia.com