1. The cell Dr.Ola Tork

2. Introduction  The smallest functional unit of the body.  Grouped together to form tissues, each of which has a specialized function e.g. blood, muscle, bone…  Different tissues are grouped together to form organs e.g heart, stomach, brain ……  Organs are grouped together to form systems,e.g. digestive system, respiratory system

4. The Cell Structure and function  A cell consists of plasma membrane inside which a number of organells in a watery fluid called cytoplasm  They are: 1. Nucleus 2. Mitochondria 3. Ribosomes 4. Endoplasmic reticulum 5. Golgi appararus 6. Lysosomes 7. Cytoskeleton

7. 1 Nucleus 2 Nuclear pore NucleusNuclear pore 3 Rough endoplasmic reticulum (RER) 4 Smooth endoplasmic reticulum (SER) 5 Ribosome on the rough ER Ribosome 6 Proteins that are transported Proteins 7 Transport vesicle vesicle 8 Golgi apparatus Golgi apparatus 9 Cis face of the Golgi apparatus 10 Trans face of the Golgi apparatus 11 Cisternae of the Golgi apparatus

8. Micrograph of Golgi apparatus, visible as a stack of semicircular black rings near the bottom. Numerous circular vesicles can be seen in proximity to the organelle

10. Plasma membrane  Two layers of phospholipids with protein and sugar molecules embedded in them  Phospholipid molecules have a head and tail  The head is electrically charged ( hydrophilic)  The tail is not charged ( hydrophobic)  The phospholipid layer is arranged like a sandwich  The heads aligned on the outer surface.  The tails form the central layer

11. The membrane proteins functions  Immunological identity ( branched carbohydrate chain)  Specific Receptors for hormones  Enzymes  Transport across the membrane

12. Nucleus  In every cell in the body, Except ?  No. ?  It is the largest organelle  It contains the body genetic material  Functions: 1. Direct all metabolic activities of the cell 2. Control reproduction of the cell

13. Mitochondia  Sausage- shaped  Power house  Involved in aerobic respiration  Synthesis of ATP  No of mitochondria ?

14. Ribosomes  Tiny granules  Composed of RNA and proteins  Synthesis of proteins  Free ribosomes

15. Endoplasmic reticulum  Series of interconnecting membranous canals  In the cytoplasm  Types: 1. Smooth ER : synthesizes lipids and steroid hormones 2. Rough ER: synthesizes proteins which are exported out side from cells

16. Golgi apparatus  Stacks of closely folde flattened membranous sacs  It is larger in cells that synthesize and export proteins  Package proteins into membrane bound vesicles (secretory granules).

17. Lysosomes  It is a type of secretory granules  Breaking down fragments of organells and large molecules inside the cells  In WBC they digest microbs

18. Cytoskeleton  Types: 1. Microfilaments 2. Microtubules 3. Centrosome 4. Cell extensions

19. Microfilaments  Smallest fibers  Functions: 1. Provide support 2. Maintain shape of the cell 3. Permit contraction ( muscle cells)

20. Microtubules  larger contractile proteins  Involved in movement of : 1. Organelles within the cell 2. Chromosomes during cell devision 3. Cell extensions

21. Centrosome  Direct organisation of microtubules within the cell  Consists of a pair of centrioles  Play important role during cell division

22. Cell extensions  They project from plasma membrane  Consists of microtubules  Types: 1. Cilia: small hair –like 2. Flagella: single long whip –like projection