Membranous Organelles PDF

Credits RESEARCH SUMMERIZING PHOTOS Merna Ahmed Mohamed Ehab Menna Allah Tarek Menna Ehab Mostafa Gamal Malak Elshamy Ali Tarek Naira Alawy Mai Mosaad Mohamed Zoer POWER POINT Mohamed Atef M...

Credits RESEARCH SUMMERIZING PHOTOS Merna Ahmed Mohamed Ehab Menna Allah Tarek Menna Ehab Mostafa Gamal Malak Elshamy Ali Tarek Naira Alawy Mai Mosaad Mohamed Zoer POWER POINT Mohamed Atef Motaz Sobhy Mohamed Zoer Motaz Sobhy Ali Tarek Merna Ahmad Mustafa Yosry Menna Allah Tarek Mariam Nasr PRESENTERS Mostafa Toema Menna Khaled Malak Elshamy Menna Alaa Menna Ashraf  CELL ORGANELLES (Covered by membrane) SER Cell Lysosome Membrane Golgi RER Bodies Mitochondr ia CELL MEMBRANE (VITAL BARRIER) Lipid Proteins CARBOHYDRATES Integral Glyco Phospholipid protein proteins Prepheral Glyco Cholesterol protein lipid  Lipids (42%) Proteins (55%) There are two main types of The cell membrane consists of a proteins: integral and peripheral. phospholipid bilayer. Integral proteins are firmly Each layer has hydrophilic head embedded phospholipid. and hydrophobic tail. Integral proteins forms channels These phospholipids arrange that allow substances get in or themselves tail to tail, creating a Carbohydrates out the cell. barrier that prevents water- soluble substances from entering Carbohydrates are part of glycolipid peripheral protein are located the cell. and glycoprotein on the cell on the inner or outer surface membrane surface. and contribute to stabilizing and Cholesterol is found between These Carbohydrates play a role in supporting the membrane phospholipid layers and is cell recognition and interaction with structure. responsible for membrane external elements. fluidity and stability.  Function of cell membrane The plasma membrane controls both the entry and exit of both solute and solvent between the cell and environment. The main functions of the cell membrane include: 1. Protecting the integrity of the interior of the cell. 2. Providing support and maintaining the shape of the cell. 3. Helps in regulating cell growth. The cell membrane also plays an important role in cell signalling and communication. It acts as a selectively permeable membrane MITOCHONDRIA (Powerhouse of the cell) Structure: composed of an outer membrane, an inner membrane, and a matrix. 1. The inner membrane has folds called cristae, which helps in increasing the surface area of the organelle. 2. The matrix is a viscous fluid that contains a mixture of enzymes and proteins which helps in the production of ATP.  Functions of Mitochondria 1- ATP production 4-Apoptosis (programmed cell death) 2-Regulation of metabolism 5- Detoxification of ammonia in liver cells 3-Calcium homeostasis  ENDOPIASMIC RETICULUM Mat of flattened sacs called cisternae and tubules made of lipid bilayers. These sacs are interconnected, forming a continuous structure. ROUGH ENDOPLASMIC RETICULUM SMOOTH ENDOPLASMIC RETICULUM DIFFERENCE It is often found connected to the nuclear it is found connected to the RER , it is envelope, allowing for direct communication abundant in lipid secreting cells such as: between the nucleus and the RER. liver cells, muscle cells and gonads. It’s called rough as it has ribosomes It’s called smooth as it doesn’t attached to its surface have ribosomes attached to its surface  Function of RER 1.Translation of mRNA by ribosomes into polypeptide chains. 2. Assistance with the synthesis and processing of proteins destined for secretion, incorporated into membranes and lysosomes. 3. Transportation of Proteins to the Golgi apparatus.  Function of SER 1. Lipid and Steroid Synthesis: SER is responsible for producing lipids, including phospholipids and cholesterol, which are important components of cell membranes. 2. Detoxification: In liver cells, the SER helps detoxify drugs, alcohol, and metabolic waste products. 3. Calcium Storage: The SER in muscle cells stores calcium ions, which are released during muscle contraction. 4. Carbohydrate Metabolism: It is also involved in the metabolism of carbohydrates, including the conversion of glycogen to glucose.  GOLGI APPARATUS The Golgi apparatus was observed in 1897 by Italian Cytologist Camillo Golgi. Golgi’s early studies of Golgi Complex were in Nervous tissue , Due to the abundance of Golgi apparatus in Nervous cells surounding the nucleus. He used (Ag stain as SP. stain to observe with L.M). The Golgi apparatus itself is structurally polarized, With three primary compartments lying between Cis and Trans surfaces.  Function of Golgi Complex Golgi apparatus plays an important role in navigation the cell vital processes , It's main function is packaging proteins coming from RER in transport vesicles and secreting it again in secretory vesicles by Trans face of Golgi apparatus. Proteins secreted by Golgi apparatus are transferred in vesicles and turned into lysosomes. Golgi apparatus also plays a role in packaging lipids. Golgi apparatus modifies some proteins before secretion by adding monosaccharaides to it, which known Glycosylation and by adding phosphate to others in a process known as phosphorylation. Also different enzyme-driven modification reactions are specific to some compartments of the Golgi apparatus such as the Removal of mannose moieties occurs primarily in the cis and medial cisternae Some modifications on transported substances involve cleavage of oligosaccharides side chains followed by attachment of different sugars in Golgi's 20th cisternae  LYSOSOME Lysosomes are rounded membranous organelles that originate from the Golgi apparatus, they contain hydrolytic enzymes so they are responsible for digestion in the cell. Site: Abundant in phagocytic cells. Types of Lysosomes: Primary Lysosomes: Newly formed from Golgi apparatus and inactive enzymes (Homogeneous). Secondary Lysosomes: These form whenever primary lysosomes fuse with phagosomes, pinocytic vesicles or old organelles Types of secondary lysosomes: 1) HETEROLYSOSOMES: 1ry lysosome +phagosome 2) MULTIVESICULAR BODIES: 1ry lysosome + pinocytic vesicle 3) AUTOLYSOSOMES: (1ry lysosome +old organelle) Residual bodies: it contains undigested materials.  Disorders concerning cell organelles Tay sachs: It is the loss of motor control, atrophy of muscles and may cause death, it is caused by genetic deficiency of lysosomal sulfatases. Alzheimer's: accumulation of misfolded proteins in the leumen of RER, Emerging evidence indicates that ER stress contributes to the onset and development of AD. Liddle Syndrome: it is a genetic disorder characterized by hypertension with hypokalemic metabolic alkalosisis, it’s caused by mutations to subunits of the Epithelial Sodium Channel (ENaC) Neonatal Jaundice: it is the accumulation of bilirubin, caused by under developed SER (Smooth endoplasmic reticulum) in liver cells of neonates. Dwarfism: it is caused by non-functioning GH (growth hormone) receptors at cell membrane of target cells or by GH deficiency.