Microbial Morphology and Classification MODULE 2 CELLS • Fundamental unit of any living organism • Categorized into two: – Eucaryotes – Procaryotes • CYTOLOGY – study of the structure and function of cells Importance identification of various microorganisms understand differences in metabolism Robert Hooke Matthias Schleiden|Theodor Schwann Botanist Zoologist The Cell Theory Schleiden Schwann Virchow • All living things are composed of cells. • Cells are the basic units of structure and function in living things. • New cells are produced from existing cells. Characteristics of life Growth Reproduction Responsiveness Metabolism Classification of Microorganisms Acellular Viroids Prions Viruses Cellular Prokaryotes Eukaryotes Archaea Bacteria Cyanobacteria Algae Fungi Protozoa Characteristics of life Growth Reproduction Responsiveness Metabolism Characteristics of life Characteristics Prokaryotes Eukaryotes Viruses Growth Occurs in all Occurs in all Reproduction Occurs in all Occurs in all Does not occur Occurs inside cells Occurs in some Uses host’s metabolism Responsiveness Occurs in all Occurs in all Metabolism Occurs in all Occurs in all CELLULAR STRUCTURE OF EUCARYOTIC CELLS Eukaryotic Cell Structure Cellular Membrane encloses and holds the cell intact Eukaryotic Cell Structure Eukaryotic Cell Structure Cellular Membrane regulates the passage of nutrients, wastes products, and secretions into and out of the cell Eukaryotic Cell Structure Nucleus differentiates prokaryotic and eukaryotic cells Eukaryotic Cell Structure Nucleus controls the function of the entire cell and acts as the command center of the cell Eukaryotic Cell Structure 3 components Nucleoplasm Chromosomes Nuclear membrane Eukaryotic Cell Structure Nuclear pores Eukaryotic Cell Structure Nucleolus dark area in the nucleus where the rRNA molecules are manufactured Eukaryotic Cell Structure Cytoplasm contains insoluble storage granules and organelles Eukaryotic Cell Structure Endoplasmic reticulum: Passageway Smooth ER without attached ribosomes and plays a role in lipid synthesis Rough ER with attached ribosomes Eukaryotic Cell Structure Ribosomes (80S): CHON synthesizers consist mainly of rRNA and protein and helps in the synthesis of proteins Eukaryotic Cell Structure Eukaryotic Cell Structure Golgi apparatus completes the transformation of newly synthesized protein into mature, functional ones Eukaryotic Cell Structure Lysosomes lysozymes and digestive enzymes break down foreign materials, cell debris or the whole cell Eukaryotic Cell Structure Eukaryotic Cell Structure Peroxisomes protects other parts of the cell from the harmful effect of hydrogen peroxide Eukaryotic Cell Structure Mitochondria site for ATP formation by cellular respiration Eukaryotic Cell Structure Eukaryotic Cell Structure Plastids energy-producing organelle containing various photosynthetic pigments Eukaryotic Cell Structure Cytoskeleton strengthens , supports and stiffens the cell giving its shape Eukaryotic Cell Structure Eukaryotic Cell Structure Cell wall external structure that provides rigidity, shape and protection Eukaryotic Cell Structure Composed of various polysaccharides unlike the prokaryotes Organism Algae Plants Fungi Composition Cellulose Cellulose Chitin/glucomannan Eukaryotic Cell Structure Flagella and cilia organelles of locomotion which is eventually necessary for survival Eukaryotic Cell Structure Eukaryotic Cell Structure Eukaryotic Cell Structure Eukaryotic Cell Structure Flagella Exhibits positive and negative phototaxis and chemotaxis but do not run and tumble CELLULAR STRUCTURE OF PROCARYOTIC CELLS Prokaryotic Cell Structure Cell membrane same in structure and function to the eukaryotic cell membrane Prokaryotic Cell Structure Mesosomes site for cellular respiration in bacteria Prokaryotic Cell Structure Chromosomes single, long, supercoiled DNA molecules Prokaryotic Cell Structure Chromosomes serves as the control center of the bacterial cell Prokaryotic Cell Structure Nucleoid DNA-occupied space within a bacterial cell Prokaryotic Cell Structure Plasmid small, circular molecules of double stranded DNA that are not part of the chromosomes Prokaryotic Cell Structure Cytoplasm semiliquid containing a complex mixture of all materials required for metabolism Prokaryotic Cell Structure Ribosomes (70S) same function with eukaryotic ribosome Prokaryotic Cell Structure Cell wall provides strong structural support that prevents the cell from bursting or collapsing Prokaryotic Cell Structure Cell wall consists of peptidoglycan (murein) Prokaryotic Cell Structure Gram positive thick layer of peptidoglycan + teichoic and lipoteichoic acid Gram negative thinner layer of peptidoglycan + complex layer of macromolecules Prokaryotic Cell Structure Gram negative Gram positive Prokaryotic Cell Structure Prokaryotic Cell Structure Prokaryotic Cell Structure Prokaryotic Cell Structure Glycocalyx thick layer of materials produced by the cell membrane and extruded outside the cell wall for protection and adhesion Prokaryotic Cell Structure Glycocalyx Slime layer Capsule Not highly organized and not firmly attached to the cell wall Highly organized and firmly attached to the cell wall Protect cells from desiccation Prokaryotic Cell Structure Glycocalyx Slime layer Capsule enables bacteria to glide and slide along solid surface serves an antiphagocytic function Prokaryotic Cell Structure Flagella Primary function: motility or selfpropulsion and eventually chemotaxis through runs and tumbles Prokaryotic Cell Structure Flagella Parts: 1. Basal body 2. Hook 3. Filament Allows 360 degrees rotation Prokaryotic Cell Structure Flagella Prokaryotic Cell Structure Flagella Monotrichous/Polar Lophotrichous Amphitrichous Peritrichous Prokaryotic Cell Structure Testing for Motility Stabbing a tiny mass of cells into soft medium Microscopically through hanging drop technique Prokaryotic Cell Structure Fimbriae (Pili) observed mostly on Gram-negative bacteria Prokaryotic Cell Structure Fimbriae (Pili) For attachment For conjugation Prokaryotic Cell Structure Endospores related to the survival l rather than on the reproduction of bacteria COMPARISON OF STRUCTURAL DIFFERENCES Prokaryotes Eukaryotes Size 10 – 100 micrometers 0.2 – 2.0 micrometers COMPARISON OF STRUCTURAL DIFFERENCES Prokaryotes Eukaryotes Nucleus Present Absent COMPARISON OF STRUCTURAL DIFFERENCES Eukaryotes Prokaryotes Glycocalyx Present in some Present as animal cells organized capsule or slime COMPARISON OF STRUCTURAL DIFFERENCES Eukaryotes Prokaryotes Motility Undulating flagella Rotating flagella COMPARISON OF STRUCTURAL DIFFERENCES Eukaryotes Prokaryotes Flagella Present in some Present in some COMPARISON OF STRUCTURAL DIFFERENCES Prokaryotes Eukaryotes Cilia Present in some Absent in all COMPARISON OF STRUCTURAL DIFFERENCES Eukaryotes Prokaryotes Fimbriae and pili Absent in all Present in some COMPARISON OF STRUCTURAL DIFFERENCES Eukaryotes Prokaryotes Cell wall Present in most Present in most COMPARISON OF STRUCTURAL DIFFERENCES Prokaryotes Eukaryotes Cytosol Present in all Present in all COMPARISON OF STRUCTURAL DIFFERENCES Eukaryotes Prokaryotes Endospore Absent in all Present in some COMPARISON OF STRUCTURAL DIFFERENCES Eukaryotes Prokaryotes Ribosomes Larger (80S) Smaller (70S) COMPARISON OF STRUCTURAL DIFFERENCES Prokaryotes Eukaryotes Nucleus Present in all Absent in all COMPARISON OF STRUCTURAL DIFFERENCES Eukaryotes Prokaryotes Nuclear membrane Present in all Absent in all COMPARISON OF STRUCTURAL DIFFERENCES Eukaryotes Prokaryotes Endoplasmic reticulum Present in all Absent in all COMPARISON OF STRUCTURAL DIFFERENCES Eukaryotes Prokaryotes Mitochondria Present in most Absent in all
