Plasma membrane presentation mmmmmm.pptx

nill

1. TOPIC: CELL MEMBRANE SCHOOL OF CLINICAL SCIENCES – MAKENI GROUP 5 Lecturer: DR. MASERAY MODULE: BIOCHEMISTRY PRESENTATION

2. PETER S. SAMURA LEADER ZAINAB KADIATU KAMARA JOHN ET KALLON NOAH JALLOH SENNATU KOROMA OSMAN CONTEH GROUP MEMBERS

3. DEFINATION OFCELL MENBRANE HISTORY OF CELL MEMBRANE STRUCTURE OF CELL MEMBRANE FUNCTION OF CELL MEMBRANE CHEMICAL COMPOSITION REACTION OF CELL MEMBRANE OUTLINE

4. CELL MEMBRANE

5. Plasma/ cell membrane The Plasma membrane or cell membrane is a thin, biological membrane present in all eukaryotic and prokaryotic cells that forms a boundary between the cell and it’s environment and regulating the flow of materials into and out of the cell. Intro:……….

6. The first incite into chemical nature of the membrane was obtained by Ernst Overtom in 1890s. He knew that the non- polar solutes dissolved very easily in the non-polar solvents then polar solvents and the polar solvents has opposite solubility. So he realised that the substances entering the cell has to be dissolved in the outer boundary of cells is due to lipids. Irvin Langmuir in 1970s doing his research in nature of oil film, found that the membrane was made of mono layers of lipids and they are arranged vertical with hydrocarbon chains away from water and carboxyl groups in contact with the surface of water. This finding was a key in understanding the lipid bilayers and cell membrane structure. History

7. the two Dutch scientists E’Gorter and F’Grendel in the 1925 were the first to find that the membrane was made of two layers of lipids (lipid bilayer) with hydrophilic heads and hydrophobic tails , but they could not explained about the solute permeability or the surface tension. In 1935 Hugh Davson and James Danielle proposed that the membrane is made of lipids bilayers and on both outer and inner surface there was a lining of globular proteins. Cont :…………

8. THE structure is made up of two micro molecules either lipids and protein . The structure of the cell membrane is not fixed neither rigid but dynamic Cell membrane structure gives the cell a unique structure and shape The cell membrane structure help to organize the cell in an organized manners The cell membrane structure allows specifics substances to enter from the environment selective permeable membrane STRUCTURE OF CELL MEMBRANE

9. The basic function of the cell membrane is to protect the cell from its surroundings Its consists of the phospholipids bilayers with embedded proteins Regulate transport in and out of the cell ( selectively permeable) Water can freely pass the membrane Contains the cytoplasm(fluid in the cell) Provide a binding sites for enzymes Allow cell recognition Ions and large molecules cannot cross without assistance Interlocking surface binds cells together (junction) Provide anchoring site for filaments of cytoskeleton Function of cell membrane(plasma)

10. Cell membranes contain a variety of biological molecules, mainly lipids and proteins. Carbohydrates are present in a very small amount, predominantly as glycoproteins. . Chemical composition of plasma membrane

11. PHOSPHOLIPIDS > 55% CHOLESTEROL =40-45% GLYCOLIPID=2% 1. MEMBRANE LIPIDS

12. They are lipids that form bilayers of plasma membrane. It contains hydro phobic tail which face towards each other and hydrophilic head facing the cytoplasm and extracellular fluid. The hydrocarbon chains forms hydrophobic tail while the phosphate group and amino acids form hydrophilic heads. The lipid bilayer is semi permeable, allowing only certain substances to diffuse through. PHOSPHOLIPIDS

13. CHOLESTEROL

14. They are lipids with a carbohydrate attached to it It provides energy and acts as markers for cellular recognition. GLYCOLIPIDS

15. Integral membrane proteins Peripheral membrane proteins Glycoproteins 2. MEMBRANE PROTEINS

16. These are proteins which are embedded within the lipid bilayer and it acts as channels through which substances diffuse between the extracellular and intracellular fluid. INTEGRAL MEMBRANE PROTEINS

17. It is attached to the inner surface of the membrane and do not penetrate the lipids bilayer. They function as enzymes and receptors. PERIPHERAL PROTEINS

18. They are embedded in the cell membrane. Its is formed by attachment of carbohydrate molecules to the protein. It helps in cell – cell communication and molecule transport across the membrane. GLYCOPROTEIN

19. Chemical reaction Passive transport In order to understand how substances move passively across a cell membrane, it is necessary to understand concentration gradient and diffusion. A concentration gradient is the different in concentration of a substance across a space. Molecules(ion) will spread or diffuse from where they are more concentrated to where they are less concentrated until they are equally distributed in that space. (when molecules move in this way, they are said to move down their concentration gradient.) Three common type of passive transport includes Simple diffusion Osmoses diffusion Facilitated diffusion REACTION OF CELL MEMBRANE

20. It is the net movement of solvents from a area of high concentration to a area of less concentration until the concentration of solute reaches the state of equilibrium. Due to lipids nature of the plasma membrane holding non-polar molecules like oxygen, carbon dioxide and nitrogen pass rapidly across the membrane according to their concentration gradient. It occurs because the molecules has free energy and they are always in motion . Simple diffusion

21. When aver a substance exists in greater concentration on one side of a semi permeable membrane, such as the plasma membrane, any substance that move down it concentration gradient across the membrane will do so . Consider substance that can easily diffuse through the lipids bilayer of the cell membrane, such as the gases, oxygen (o2) and CO2. O2 generally diffuse into the cell membrane it is more concentrated outside of them and CO2 typically diffused out of the cells because it more concentrated inside of them. Neither of these examples requires any energy on the part of cell membrane and therefor they use passive transport to move across the membrane. Cont …….

22. Osmosis is the diffusion of water through a semi permeable membrane water can move freely across the cell membrane of all cells either through protein channels or by slipping between the lipids tails of the membranes itself . However, it is concentration of solute within the water that determine weather or not water will be moving into the cell, out of the cell, or both. Osmosis

23. Facilitated diffusion is the diffusion process used for those substances that cannot cross the lipid bilayer due to their side and or polarity a common examples of facilitated diffusion is the movement of glucose into the cell, where it is use to make ATP. Although glucose can be more concentrated outside of the cell, it cannot cross the lipids bilayers via simple diffusion because it is both large and polar. to resolve this, a specialized carrier protein call the glucose transporter will transfer glucose molecule into the cell to facilitate it inward diffusion. There are many other solute that most undergo facilitated diffusion into the cell, such as amino acid or to move out of the cell such as wastes. Because facilitated diffusion is a passive process, it does not required energy expenditure by the cell . Facilitated diffusion

24. it is the transport of molecules across the cell membrane from an area of low concentration to and area of high concentration using cellular energy . Active transport occurs with the help of carrier proteins. There are two actives site in this carrier proteins. One it receptors site which is recognizes the substances to be carried and the other it that which releases the energy in form of ATP. Example transportation of sodium out of cell and potassium into the cell. Active transport

25. There are two form of active transport Primary active transport Secondary active transport Form of active transport

26. When the process used chemical energy in the form of ATP, redox energy or photon energy to transport substances across the membrane, it is call primary active transport The energy is derived directly from the breakdown of the ATP or some other high energy phosphate compounds. The protein act as point to transport ions most of the enzymes that perform this transport are transfers membrane ATP- ase then the primary ATP- ase which is universal to all animal cell is sodium-potassium pump which maintains the cell potential. Primary active transport

27. When the process use electrochemical gradient to transport substances it is called secondary active transport here the energy is derived secondarily from the energy that has been stored in the form of ionic concentration difference between the two site of the membrane, created in the first place by primary active transport. The pore forming proteins acts as channels across the cell membrane for transporting substances the energy stored in Na+ , H+ concentration gradient is used to transport other solutes or ions. Secondary active transport

28. By Harshraj s shinde K.k. Wagh colledge of Agrculture Biotechnology Dr.Areeba Ghayas Refrences

29. Thanks!!! Any questions