Cell Wall
• Outermost bondary –> plant cell.,• Cell Wall of plant cell –> different –> from prokaryotes both in structure and composition.
• Secreted by protoplasm of cell.
• Three main layer are:
Primary
Secondary
Middle Lamella(outermost layer)
1. Primary: Composed of cellulose pectin and hemicellulose. Cellulose arrange in criss cross arrangement.True wall, develop in newly group cell.
2. Secondary: Formed on inner surface of primary. Thick and rigid composition. Inorganic salts, silica, Waxes, cutin, lisnin.
3. Middle Lamella(outermost layer): Formed in between primary and walls of neighboring cells.
• Fungal cell (wall–>) chitin.
• Prokaryotic cell –> lacks cellulose –> peptiglycan or murine.
Function:
• Definite shape to cell and rigidity.
• Does not act as barrier to material passing through it.
Cytoplasm
• Eukaryotic living contents –> nucleus (protoplasm) + cytoplasm.• Aqeous ground –> variety of organelles and insoluble waters and storage products.
• Cytosol –> Soluble part of cytoplasm (forms ground substance of cytoplasm). Small molecules and ions form true solution. large molecules –> collidal solution –> sol (non-viscous), gel (viscous), peripheral parts.
Function:
• Storehouse of vital chemicals.
• Site of metabolic process e.g: glycolysis.
• Living cell cytoplasm –> ER + Mitochondria + Golgi complex + nucleus + plastids + ribosomes + lysosomes + centrioles.
• Active movement of cytoplasm –> mitochondria movevin cytoplasm due to cytoplasmic streaming.
Endoplasmic Reticulum
• Network of channels –> extending or expanding throughout cytoplasm.• Continues with plasma membrane + in contact with nuclear membrane.
• Citernae –> Materials of these channels separate from cytoplasm material through Spherical or tubular membrane cisternae.
Tyes:
RER
• Rough form attached with ribosomes.• Synthesis of protein.
• After synthesis protein either stored in cytoplasm or exported out of cell through RER by transport vesicle.
e.g: insulin of pancreas.
• RER –> membrane making machine of cell.
SER:
• Smooth form without ribosomes.• Synthesis –> oil, Phospholipids, steroids.
• Metabolism of lipids.
• Detoxify harmful drugs in liver.
• Transmission of impulse i.e muscle or nerve cell.
• Transport of material starting, from one part to another part.
• Storage of Ca+ ions.
Ribosomes:
Palade In 1955 discovered tiny glanular structure. Eukaryotic ribosomes –> RNA and protein (equal amount ribonucleo proteins.• RNA of ribosomes –> ribosomnal RNA.
• Two Form Ribosomes:
Either freely dispered in cytoplasm.
Attached with RER.
Eukaryotic ribosomes –> two subunits.
Two subunits: • Lager sediments at 605 –> Svedberg unit. • Smallest at 405
805 particle attachment is controlled by Mg²+ ions.
Polysomes:
• Group of ribosomes attached to mRNA through small unit.• New ribosomes –> assembled –> nucleolus of transport to cytoplasm via pores in nuclear membrane.
• Factory of ribosomes –> nucleolus.
• Factory of Protein –> ribosomes synthesis.
Golgi Apparatus
• Golgi in 1898.
• In all ekaryotics cell.
• Stacks of flattened –> layer limited or membrane bounded sacs called cisternae.
• Cisternae and associated vesicle.
• Cisternae –> Golgi complex.
• Cisternae –> sacs are formed by fusion of vesicle –> derived from budding of SER.
• Outer convex Face –> Forming face.
• Inner convex Face –> maturing face.
Function:
• Cell secreting products.
• Secretions are formed cell on ribosomes –> passed out –> ER and Golgi.
• Secretions –> packed in finished.
• Products –> packed inside membrane before Exports.
• Most important function –> modification of protein and lipids by adding CHO make glycoprotein and Glycolipid.
• In all ekaryotics cell.
• Stacks of flattened –> layer limited or membrane bounded sacs called cisternae.
• Cisternae and associated vesicle.
• Cisternae –> Golgi complex.
• Cisternae –> sacs are formed by fusion of vesicle –> derived from budding of SER.
• Outer convex Face –> Forming face.
• Inner convex Face –> maturing face.
Function:
• Cell secreting products.
• Secretions are formed cell on ribosomes –> passed out –> ER and Golgi.
• Secretions –> packed in finished.
• Products –> packed inside membrane before Exports.
• Most important function –> modification of protein and lipids by adding CHO make glycoprotein and Glycolipid.
Lysosymes
• Protects cell from foreign organisms.• Cytoplasm organelle –> different from others due to morphology.
• In 1949, Deduve –> (Lyso –> splitting, Soma = body).
• Found in Eukaryotes.
• Phagocytosis –> any foreign particles that enters the cell –> captured by lysosyme –> broken down into digestable Pieces.
• Most abudant in animal with phygocytic activity (eating process of cell).
• Single membrane bounded –> sacs rich in acid phosphatase and several hydrolytic.
• Enzyme –> These enzymes are synthesis on RER –> further processed in Golgi Apparatus –> Processed enzyme –> bud off –> from 95 golgi vesicles –> known as primary lysosymes.
• Lysosymes –> contain enzymes –> that digest Phagocytosed food.
Function:
Enzyme function: Autophagy (self eating). Some old, worn-out parts of cell are digested.
e.g: Old mitochondria –> materials of cell recycled and renewed. Degeneration of cell –> that may occur during developmental process.
Lysosomes –> release enzyme –> for extracellular digestion.
Congenital Diseases:
• Due to accumulation within the cell of substance i.e. Olycogen and Olycolipids.
• Also known as storage diseases –> produced by mutation –> effect one of lysosomal enzyme –> involved in catabolism of certain substance. e.g: Glycogenesis Type 2 –> Liver and muscle appear –> filled with glycogen –> within membrane bounded organelli. –> Enzyme that converts glycogen – to glucose is absent or missing.
• Twenty such disease known –> absence of particles enzyme.
e.g: Tay-Sach disease: absence of Enzyme involved in catabolism of lipids –> accumulation of lipids in brain cell –> mental retardation and de@th.
Peroxisomes
• In 1965; Deduve and coworkers –> from liver cell –> and other tissues enriched with oxidative enzyme. e.g: prooxidase, catalase, glycolic acid oxidase.Name peroximes –> because this organelle –> involved in fomation and decomposition of H²O² in cell. –> Produce oxidase and catalase.
Structure:
• Single membrane founded cytoplasmic organelle.
• Both in animal and plant cell.
• 0.5μm in Diameter.
• 9150 found in protozoa, yeast many cell of higher plants.
Glyoxysomes
• Present in plants seeding –> abudant• For a short period in germination of lipids in seed, absent in lipid poor seed i.e. Pea.
• Contain glycolic acid oxidase and catalase also Process –>number of enzyme not found in animal cell.
• Plant Seedings rely upon stored fatty acid that provide them energy and material –> to begin the formation of new plant.
Function:
Germination seeding –> converts stored fatty acid into carbohydrates –> through –> Glyoxylate cycle.
Enzymes of Glyoxylate cycle are located in glyoxysomes.
Function:
• Play role in catabolic and anabolic pathways.
• Glyoxymes –> sites for breakdown of fatty acid to succinate –> in lipid rich seeds i.e: castor bean and soya bean.
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