Cell Physiology Overview PDF

OVERVIEW OF CELL PHYSIOCHEMISTRY University of the Philippines Los Baños COLLEGE OF VETERINARY MEDICINE LEVELS OF STRUCTURE Atoms (elements) Molecules CELLS - basic structural & functional units TISSUE - cells having similar characteristics ORGANS ORGAN SYSTEM ORGANISM...

OVERVIEW OF CELL PHYSIOCHEMISTRY University of the Philippines Los Baños COLLEGE OF VETERINARY MEDICINE LEVELS OF STRUCTURE Atoms (elements) Molecules CELLS - basic structural & functional units TISSUE - cells having similar characteristics ORGANS ORGAN SYSTEM ORGANISM C O L L E G E O F VE T E RI N AR Y M E D I C IN E D epartment of B asic V eterinary Scienc es TYPES OF CELLS 1. Prokaryotes 2. Eukaryotes Constructed by microbiologist Carl Woese using data obtained from sequencing ribosomal RNA genes. (credit: Eric Gaba; NASA Astrobiology Institute) C O L L EG E O F V E TE R IN A R Y M E D I C IN E D e pa r tm en t of Ba s ic Ve te r i na r y S cie n ce s PROKARYOTES vs EUKARYOTES C O L L E G E O F VE T E RI N AR Y M E D I C IN E D epartment of B asic V eterinary Scienc es SIMILARITIES BETWEEN PROKARYOTES & EUKARYOTES STRUCTURES PROKARYOTE EUKARYOTE Plasma membrane + + Cytoplasm + + Ribosomes + + (70s=50s, 30s) (80s=60s, 40s) + + DNA Circular, double-stranded; in cytoplasm; Linear, double-stranded; in nucleus. Not bound to proteins Bound to HISTONE proteins. Plasmid + + extra-chromosomal DNA important for antibiotic resistance Fungi; Saccharomyces cerevisiae Cell wall + + Peptidoglycan/ mucopeptiide; Absent in Mycoplasma spp. Plant cell - pectin, cellulose, Fungi - chitin Cytoskeleton + + actin, tubulin, flagellin microtubules, microfilaments, intermediate filaments C O L L E G E O F VE T E RI N AR Y M E D I C IN E D epartment of B asic V eterinary Scienc es DIFFERENCES BETWEEN PROKARYOTES & EUKARYOTES Parameters PROKARYOTE EUKARYOTE Size (in diameter) 0.1 - 5.0 μm 10 - 100 µm Nucleus - ; nucleoid (no membrane) +; membrane-bound Chromosome Number Single haploid (n) chromosome Paired diploid (2n) chromosome Intracellular many few membranes - membrane bound organelles Site of RNA & protein Nucleus - RNA synthesis same compartment synthesis Cytoplasm - protein synthesis Cell movement Flagella - flagellin Flagella, cilia - tubulin Metabolism of energy aerobic or unaerobic aerobic substrates Method of Asexual- binary fission Mitosis, meoisis reproduction C O L L E G E O F VE T E RI N AR Y M E D I C IN E D epartment of B asic V eterinary Scienc es  PERCENT OF TOTAL CELL WEIGHT COMPONENT E. coli BACTERIUM MAMMALIAN CELL H 2O 70 70 Inorganic ions + + 2+ 2+ - 1 1 (Na , K , Mg , Ca , Cl , etc.) Miscellaneous small metabolites 3 3 Proteins 15 18 RNA 6 1.1 DNA 1 0.25 Phospholipids 2 3 Other lipids - 2 Polysaccharides 2 2 -12 3 -9 3 TOTAL CELL VOLUME 2 × 10 cm 4 × 10 cm RELATIVE CELL VOLUME 1 2000 CHEMICAL COMPONENTS OF THE EUKARYOTIC CELL LIPIDS 5% POLYSACCHARIDES 2% NUCLEIC ACIDS 1.25% PROTEINS 18% METABOLITES 3% WATER INORGANIC IONS 1% 70% C O L L E G E O F VE T E RI N AR Y M E D I C IN E D epartment of B asic V eterinary Scienc es  comprise 70-85% of the inner cell mass WATER principal fluid medium of the cell Functions of Water in the Body 1. serves as solvents for ions, macromolecule 2. acts as chemical reactant (hydrolysis) 3. serves as medium for transport (blood, bile, urine, milk) 4. acts as lubricants (joints) –SYNOVIAL FLUIDS 5. regulates body temperature  ELECTROLYTES - provides the inorganic substances needed for cellular reactions Most important electrolytes in the cell: a. K e. Mg b. Cl f. HCO3 c. Ca g. Na d. PO4 h. SO4 C O L L E G E O F VE T E RI N AR Y M E D I C IN E D epartment of B asic V eterinary Scienc es PROTEINS 2nd most abundant substance in the cell constitute 10-20% of the inner cell mass Two Types of Proteins in the Cell Fibrous Protein Globular Protein C O L L E G E O F VE T E RI N AR Y M E D I C IN E D epartment of B asic V eterinary Scienc es Types of Proteins in the Cell Simple Proteins Conjugated Proteins glycoproteins albumins lipoproteins globulins nucleoproteins protamines chromoproteins histones metalloproteins albuminoids phosphoproteins C O L L E G E O F VE T E RI N AR Y M E D I C IN E D epartment of B asic V eterinary Scienc es LIPIDS constitute 2% of inner cell mass polar cell substances (soluble in lipid solvents) consist primarily of C, H, O2 Importance of the Lipids 1. provide an important form of energy storage 2. major components of cell membranes 3. play important roles in cell signaling C O L L E G E O F VE T E RI N AR Y M E D I C IN E D epartment of B asic V eterinary Scienc es TRIGLYCERIDES C O L L E G E O F VE T E RI N AR Y M E D I C IN E D epartment of B asic V eterinary Scienc es PHOSPHOLIPIDS C O L L E G E O F VE T E RI N AR Y M E D I C IN E D epartment of B asic V eterinary Scienc es CHOLESTEROL C O L L E G E O F VE T E RI N AR Y M E D I C IN E D epartment of B asic V eterinary Scienc es CARBOHYDRATES comprise 1% of the inner cell mass provides nutrition to the cell 1. monosaccharides glucose, galactose, fructose 2. disaccharides sucrose, lactose, maltose 3. polysaccharide glycogen Stored form of CHO: Glycogen (insoluble form of glucose) Site of Storage: liver & skeletal muscle cells ( C O L L E G E O F VE T E RI N AR Y M E D I C IN E D epartment of B asic V eterinary Scienc es MONOSACCHARIDES C O L L E G E O F VE T E RI N AR Y M E D I C IN E D epartment of B asic V eterinary Scienc es DISACCHARIDES C O L L E G E O F VE T E RI N AR Y M E D I C IN E D epartment of B asic V eterinary Scienc es DISACCHARIDES MALTOSE ISOMALTOSE CELLOBIOSE 2-⍺- glucose 2-⍺- glucose 2-β- glucose ⍺-1.4-glucosidic bond ⍺-1.6-glucosidic bond β-1.4-glucosidic bond From hydrolysis of polysaccharides From starch by amylose action from acid hydrolysis of cellulose (e.g. dextran) C O L L E G E O F VE T E RI N AR Y M E D I C IN E D epartment of B asic V eterinary Scienc es 2 MAJOR COMPARTMENTS OF THE EUKARYOTIC CELL 1. Nucleus 2. Cytoplasm C O L L E G E O F VE T E RI N AR Y M E D I C IN E D epartment of B asic V eterinary Scienc es NUCLEUS C O L L E G E O F VE T E RI N AR Y M E D I C IN E D epartment of B asic V eterinary Scienc es NUCLEAR MEMBRANE OR ENVELOPE C O L L E G E O F VE T E RI N AR Y M E D I C IN E D epartment of B asic V eterinary Scienc es NUCLEOPLASM C O L L E G E O F VE T E RI N AR Y M E D I C IN E D epartment of B asic V eterinary Scienc es CHROMATIN C O L L E G E O F VE T E RI N AR Y M E D I C IN E D epartment of B asic V eterinary Scienc es C O L L E G E O F VE T E RI N AR Y M E D I C IN E D epartment of B asic V eterinary Scienc es  NUCLEOLUS - RNA containing body, # varies from 1 to 4 in normal growing cells 1. Site of ribosome synthesis 2. Produces rRNA C O L L E G E O F VE T E RI N AR Y M E D I C IN E D epartment of B asic V eterinary Scienc es RIBOSOMES C O L L E G E O F VE T E RI N AR Y M E D I C IN E D epartment of B asic V eterinary Scienc es RIBOSOMES EUKARYOTE PROKARYOTE MITOCHONDRION Other names cytoplasmic ribosome cytoplasmic ribosome mitoribosomes Location free or rough ER free in cytoplasm free in matrix Size 25-30 nm 20 nm 20 nm rRNA/protein ratio 50:50 65:35 * Whole unit 80S** 70S 55S Subunit 40S and 60S 30S and 50S 28S and 39S rRNA per ribosome 4 3 2 or 3 rRNA 28, 15, 5.8, 5S 23, 16, 5S 16, 12S C O L L E G E O F VE T E RI N AR Y M E D I C IN E D epartment of B asic V eterinary Scienc es RIBOSOMES 70S C O L L E G E O F VE T E RI N AR Y M E D I C IN E D epartment of B asic V eterinary Scienc es Types of Ribosomes Free Ribosomes Bound Ribosomes Location cytoplasm attached to RER Arrangement linked together in chains singly site of protein synthesis for site of protein synthesis for Functions intracellular use extracellular use Polyribosomes OR C O L L E G E O F VE T E RI N AR Y M E D I C IN E D epartment of B asic V eterinary Scienc es CYTOPLASM C O L L E G E O F VE T E RI N AR Y M E D I C IN E D epartment of B asic V eterinary Scienc es C O L L E G E O F VE T E RI N AR Y M E D I C IN E D epartment of B asic V eterinary Scienc es  CELL ORGANELLES Non-membrane bound Membrane bound nucleus, mitochondria, ribosomes, microtubules endoplasmic reticulum, microfilaments intermediate filaments lysosomes, peroxisomes, Golgi apparatus C O L L E G E O F VE T E RI N AR Y M E D I C IN E D epartment of B asic V eterinary Scienc es MITOCHONDRIA C O L L E G E O F VE T E RI N AR Y M E D I C IN E D epartment of B asic V eterinary Scienc es  Parts of the Mitochondria & their Functions MITOCHONDRIAL MATRIX INNER MEMBRANE OUTER MEMBRANE - dense with DNA, large phosphate - contains enzymes for oxidative - outer covering of granules & ribosomes phosphorylation the mitochondria - mitochondrial ribosomes are smaller - contains electron carriers for than cytoplasmic ribosomes the electron transport system - contains enzymes for Kreb cycle & - possess F1 factor or ATP beta oxidation of fats synthase during cellular respiration C O L L E G E O F VE T E RI N AR Y M E D I C IN E D epartment of B asic V eterinary Scienc es ENDOMEMBRANE SYSTEM ENDOPLASMIC RETICULUM C O L L E G E O F VE T E RI N AR Y M E D I C IN E D epartment of B asic V eterinary Scienc es Rough ER & Smooth ER C O L L E G E O F VE T E RI N AR Y M E D I C IN E D epartment of B asic V eterinary Scienc es Types of ER & Their Functions RER or Granular ER SER or Agranular ER extensive tubules with ribosomes round tubules continuous with the outer nuclear lacks ribosomes membrane site of protein synthesis for Site of: extracellular use lipid synthesis example: hormones processing of synthesized proteins detoxification of foreign substances 4 C O L L E G E O F VE T E RI N AR Y M E D I C IN E D epartment of B asic V eterinary Scienc es 0 Rough ER & Smooth ER C O L L E G E O F VE T E RI N AR Y M E D I C IN E D epartment of B asic V eterinary Scienc es GOLGI APPARATUS C O L L E G E O F VE T E RI N AR Y M E D I C IN E D epartment of B asic V eterinary Scienc es OTHER FUNCTIONS - production of lysosomes - further processing of macromolecules from SER C O L L E G E O F VE T E RI N AR Y M E D I C IN E D epartment of B asic V eterinary Scienc es VESICLES LYSOSOMES C O L L E G E O F VE T E RI N AR Y M E D I C IN E D epartment of B asic V eterinary Scienc es SYNTHESIS OF LYSOSOMES C O L L E G E O F VE T E RI N AR Y M E D I C IN E D epartment of B asic V eterinary Scienc es LYSOSOMES: PROTON PUMP Lysosomal enzymes - digest proteins, CHO, fats - functions best under slightly acidic condition (pH 3.5 to 5.0) - maintain acidic env’nt through proton pump C O L L E G E O F VE T E RI N AR Y M E D I C IN E D epartment of B asic V eterinary Scienc es LYSOSOMAL ENZYMES Enzymes Substrate Digested Lipase - lipids Carbohydrases - CHO Proteases - proteins Nucleases - nucleic acids C O L L E G E O F VE T E RI N AR Y M E D I C IN E D epartment of B asic V eterinary Scienc es Lysosomal Enzymes Engulfs (endocytosis) & Cause Autolysis of: 1. degenerating cell components- Autophagic vacuole 2. bacteria or foreign substances- Phagocytic vacuole C O L L E G E O F VE T E RI N AR Y M E D I C IN E D epartment of B asic V eterinary Scienc es Other Functions of Lysosomes C O L L E G E O F VE T E RI N AR Y M E D I C IN E D epartment of B asic V eterinary Scienc es PEROXISOMES - small membrane-bound vesicle (0.2 to 0.5 um) containing oxidative enzymes involved in: - oxidation of very long chain fatty acids (FA) - generation & destruction of hydrogen peroxide C O L L E G E O F VE T E RI N AR Y M E D I C IN E D epartment C O L L E G E of O FB asic V E TV E eterinary Scienc RI N AR Y M E D I Ces IN E D epartment of B asic V eterinary Scienc es PEROXISOMAL BIOGENESIS C O L L E G E O F VE T E RI N AR Y M E D I C IN E D epartment C O L L E G E of O FB asic V E TV E eterinary Scienc RI N AR Y M E D I Ces IN E D epartment of B asic V eterinary Scienc es PEROXISOMAL ENZYMES 1. Catalase 2. Urate oxidase 3. D-amino oxidase C O L L E G E O F VE T E RI N AR Y M E D I C IN E D epartment C O L L E G E of O FB asic V E TV E eterinary Scienc RI N AR Y M E D I Ces IN E D epartment of B asic V eterinary Scienc es SECRETORY VESICLES C O L L E G E O F VE T E RI N AR Y M E D I C IN E D epartment of B asic V eterinary Scienc es CYTOSKELETON C O L L E G E O F VE T E RI N AR Y M E D I C IN E D epartment of B asic V eterinary Scienc es CYTOSKELETON COMPONENTS DESCRIPTION DIAMETER 1. Microfilaments (Actin) smallest 7 nm 2. Intermediate filaments medium size 10 nm 3. Microtubules (tubulin) largest 25 nm C O L L E G E O F VE T E RI N AR Y M E D I C IN E D epartment of B asic V eterinary Scienc es MICROFILAMENTS C O L L E G E O F VE T E RI N AR Y M E D I C IN E D epartment of B asic V eterinary Scienc es FUNCTIONS OF MICROFILAMENTS C O L L E G E O F VE T E RI N AR Y M E D I C IN E D epartment of B asic V eterinary Scienc es FUNCTIONS OF MICROFILAMENTS C O L L E G E O F VE T E RI N AR Y M E D I C IN E D epartment of B asic V eterinary Scienc es FUNCTIONS OF MICROFILAMENTS C O L L E G E O F VE T E RI N AR Y M E D I C IN E D epartment of B asic V eterinary Scienc es FUNCTIONS OF MICROFILAMENTS C O L L E G E O F VE T E RI N AR Y M E D I C IN E D epartment of B asic V eterinary Scienc es INTERMEDIATE FILAMENTS C O L L E G E O F VE T E RI N AR Y M E D I C IN E D epartment of B asic V eterinary Scienc es Major Mammalian Intermediate Filament Proteins INTERMEDIATE FILAMENT PROTEIN PRIMARY TISSUE DISTRIBUTION Keratin I, II epithelia Vimentin mesenchymal cells Desmin muscle Glial Fibrillary Acidic Proteins (GFAP) glial cells, astrocytes peripherin peripheral neurons Neurofilament proteins (NF) neurons of central and peripheral nerves (NF-L, NF-M, NF-H) Lamin Proteins (A, B, C) all cells Nestin neuronal stem cells C O L L E G E O F VE T E RI N AR Y M E D I C IN E D epartment of B asic V eterinary Scienc es Functions of Intermediate Filaments C O L L E G E O F VE T E RI N AR Y M E D I C IN E D epartment of B asic V eterinary Scienc es MICROTUBULE C O L L E G E O F VE T E RI N AR Y M E D I C IN E D epartment of B asic V eterinary Scienc es Functions of Microtubules 1. Mechanical & structural function 2. Placement & movement of organelles 3. Cell division 4. Main component of cilia & flagella 5. Cellular Motility or movement 6. Transport of macromolecules within the cell C O L L E G E O F VE T E RI N AR Y M E D I C IN E D epartment of B asic V eterinary Scienc es FUNCTIONS OF MICROTUBULES C O L L E G E O F VE T E RI N AR Y M E D I C IN E D epartment of B asic V eterinary Scienc es CENTROSOME C O L L E G E O F VE T E RI N AR Y M E D I C IN E D epartment of B asic V eterinary Scienc es  CENTRIOLES - short cylinders located near the nucleus, arranged at right angles to one another - each centriole is made up of 9 bundles of microtubules (3 per bundle) arranged in a ring C O L L E G E O F VE T E RI N AR Y M E D I C IN E D epartment of B asic V eterinary Scienc es CILIA AND FLAGELLA CILIA FLAGELLA long projections in at the cell apex short projections transport of materials along cell surface motility of sperm a. kinocilia - true cilia b. stereocilia epithelial cells of respiratory tract, tail of sperms reproductive tract Parts of Cilia & Flagella C O L L E G E O F VE T E RI N AR Y M E D I C IN E D epartment of B asic V eterinary Scienc es  SLIDING OF MICROTUBULES - causes cilia or flagella to move, bend C O L L E G E O F VE T E RI N AR Y M E D I C IN E D epartment of B asic V eterinary Scienc es  MICROTUBULE FOR TRANSPORT OF SUBSTANCES - provide tracks for transport of vesicles, secretory granules from mitochondria or in axons of neurons C O L L E G E O F VE T E RI N AR Y M E D I C IN E D epartment of B asic V eterinary Scienc es CYTOSKELETON C O L L E G E O F VE T E RI N AR Y M E D I C IN E D epartment of B asic V eterinary Scienc es CYTOSKELETON C O L L E G E O F VE T E RI N AR Y M E D I C IN E D epartment of B asic V eterinary Scienc es C O L L E G E O F VE T E RI N AR Y M E D I C IN E D epartment of B asic V eterinary Scienc es MEMBRANOUS STRUCTURES OF THE CELL Different Membranes in the Cell: essentially most cell organelles are enclosed by membranes - cell membrane - nuclear membrane - membrane of the ER - membrane of the mitochondria - membrane of lysosomes - membrane of Golgi apparatus C O L L E G E O F VE T E RI N AR Y M E D I C IN E D epartment of B asic V eterinary Scienc es CELL MEMBRANE C O L L E G E O F VE T E RI N AR Y M E D I C IN E D epartment of B asic V eterinary Scienc es Functions of Cell Membrane 1. transport of substances including water 2. protective function 3. enzymatic activity 4. involved in signal transduction 5. involved in intercellular junction & communication between adjacent cells 6. involved in cell to cell recognition – specifically the glycoprotein serving tags for recognition by other cells 7. involved in the maintenance of cell shape - attachment to cytoskeleton & extracellular matrix of the cell 8. coordination of extracellular changes C O L L E G E O F VE T E RI N AR Y M E D I C IN E D epartment of B asic V eterinary Scienc es Components of Cell Membrane Proteins 55% Lipids 42% Carbohydrates 3% C OL LE8 G E O F VE T E RI N AR Y M E D I C IN E D epartment of B asic V eterinary Scienc es 1 A. Cell Membrane Lipids - consists of phospholipids, cholesterol, glycolipids TYPES OF MEMBRANE PHOSPHOLIPIDS COMPOSITION LOCATION 1. Phosphatidyl-choline glycerol choline + FA (2) + phosphorylated alcohol outer part 2. Sphingomyelins sphingosine backbone + FA(2) + phosphoylated alcohol outer part 3. Phosphatidyl-serine serine backbone + FA (2) + phosphoylated alcohol inner part 4. Phosphatidyl-ethanolamine ethanolamine backbone + FA (2) + phosphoylated alcohol inner part 5. Phosphatidyl-inositol inositol backbone + FA (2) + phosphoylated alcohol inner part C O L L E G E O F VE T E RI N AR Y M E D I C IN E D epartment of B asic V eterinary Scienc es Cell Membrane Phospholipid C O L L E G E O F VE T E RI N AR Y M E D I C IN E D epartment of B asic V eterinary Scienc es  Two Heads or Ends of the Cell Membrane HYDROPHILIC END HYDROPHOBIC END water loving or polar end of the non-water loving or nonpolar end of cell membrane the cell membrane part of cell membrane exposed part of cell membrane that meets the to the aqueous env’t that bathes water poor interior of the cell the cell exterior & cytoplasm Important in preventing escape of most of the water soluble substance in the cytoplasm C O L L E G E O F VE T E RI N AR Y M E D I C IN E D epartment of B asic V eterinary Scienc es Two Ends of the Cell Membrane C O L L E G E O F VE T E RI N AR Y M E D I C IN E D epartment of B asic V eterinary Scienc es Cell Membrane (CM) Sterols & Glycolipids CHOLESTEROL GLYCOLIPIDS - most common sterol in the cell membrane - sugar or CHO containing lipids (CM) - located in the outer CM - exists exclusively in the animal CM - E.g. Cerebrosides and gangliosides - more abundant in the outer CM - intercalates among the CM phospholipids to maintain cell membrane fluidity C O L L E G E O F VE T E RI N AR Y M E D I C IN E D epartment of B asic V eterinary Scienc es Cell Membrane (CM) Sterols & Glycolipids C O L L E G E O F VE T E RI N AR Y M E D I C IN E D epartment of B asic V eterinary Scienc es  CELL MEMBRANE FLUIDITY 1. presence of cholesterol among the membrane 2. phospholipids increased in unsaturation of fatty acid (FA) during low environmental temperature 3. movement of CM phospholipids a. longitudinal axis rotation b. lateral movement c. transverse (flip flop, catalyzed by flippase) movement C O L L E G E O F VE T E RI N AR Y M E D I C IN E D epartment of B asic V eterinary Scienc es MAINTENANCE OF CELL MEMBRANE FLUIDITY C O L L E G E O F VE T E RI N AR Y M E D I C IN E D epartment of B asic V eterinary Scienc es B. Cell Membrane Carbohydrates CELL COAT Oligosaccharides & Polysaccharides - covalently bound to proteins Oligosaccharides - covalently bound to lipids C O L L E G E O F VE T E RI N AR Y M E D I C IN E D epartment of B asic V eterinary Scienc es C. Cell Membrane (CM)Proteins responsible for the functional behavior of the CM held in place by attaching to the cytoskeleton in the cytoplasm & extracellular cell matrix INTRINSIC PROTEINS EXTRINSIC PROTEINS integral, penetrating or transmembrane peripheral or surface protein located protein - a-helix protein which consists of - found in the inner & outerCM - loosely peripherally located hydrophilic & inner bound to the surface of the CM hydrophobic amino acids(AA) which passes - some of the peripherally located proteins through the CM are attached to CHO to form “glycoprotein” C O L L E G E O F VE T E RI N AR Y M E D I C IN E D epartment of B asic V eterinary Scienc es Cell Membrane Proteins Amphipathic proteins can integrate into membrane bilayers Intrinsic Proteins are predominantly ∝ helices. C O L L E G E O F VE T E RI N AR Y M E D I C IN E D epartment of B asic V eterinary Scienc es C O L L E G E O F VE T E RI N AR Y M E D I C IN E D epartment of B asic V eterinary Scienc es  Questions? University of the Philippines Los Baños COLLEGE OF VETERINARY MEDICINE