Cell Organelles ‘the intracellular specialty shop’ Dr. Sadaf Mumtaz 8/12/11

The cell

Cytosol

Endoplasmic Reticulum

Functions of ER Rough ER Smooth ER Protein synthesis Central packaging and discharge site Lipid synthesis (some) Lipid synthesis (mainly) Modification of newly synthesized protein Detoxifying enzymes Replacement of used up membrane Stores Calcium in muscle cells Provides enzymes for glycogenolysis

Golgi apparatus

Lysosomes Enzyme Substrate Ribonuclease RNA Deoxyribonuclease DNA Phosphatase Phosphate esters Glycosidases Complex carbohydrates Arylsulfatases Sulfate esters Collagenase Collagens Cathepsins Proteins

Pinocytosis

Phagocytosis

Lysosomal storage diseases Enzyme deficient Disease manifested α-galactosidase (biodegradation of a glycolipid) Fabry disease (blood vessels, tissues etc) (Pain, Cardiac, Renal, GI manifestations) β-galactocerebrosidase (biodegradation of a lipid) Gauchers disease (WBC) Hexosaminidase (biodegradation of FA derivatives) Tay-Sachs disease (nerves) (Blindness, deafness, muscle weakness)

Peroxisomes Oxidase enzymes RH2 + O2------R + H2O2 Catalase utilizes the H2O2 generated by other enzymes in the organelle to oxidize a variety of other substrates—including phenols, formic acid, formaldehyde, and alcohol—by the “peroxidative” reaction: H2O2 + R′ H2 → R′ + 2H2O. This type of oxidative reaction is particularly important in liver and kidney cells, where the peroxisomes detoxify various toxic molecules that enter the bloodstream. In addition, when excess H2O2 accumulates in the cell, catalase converts it to H2O. Single peroxisomal enzyme deficiencies and peroxisomal biogenesis disorders

Mitochondria

Glycolysis

Citric acid cycle

Electron transport chain

Activation of ATP synthase

Uses of ATP

Vaults Speculations ---- Chemotherapeutic drug resistance in cancer cells

Cytosol Storage house Enzymatic reactions Ribosomal protein synthesis

Thanks