V. Micro 151 General Veterinary Microbiology Past Paper PDF

V. MICRO 151: GENERAL VETERINARY MICROBIOLOGY MODULE 02: PROKARYOTIC AND EUKARYOTIC CELLULAR STRUCTURE 1st Semester | S.Y. 2023-2024 Instructor: Dr. Precy D. Magtoto Program, Yr., and Section: DVM 3D Transcribe...

V. MICRO 151: GENERAL VETERINARY MICROBIOLOGY MODULE 02: PROKARYOTIC AND EUKARYOTIC CELLULAR STRUCTURE 1st Semester | S.Y. 2023-2024 Instructor: Dr. Precy D. Magtoto Program, Yr., and Section: DVM 3D Transcribed By: Harold B. Lacumbes Prokaryotic vs. Eukaryotic Cells slime layer Present, Prokaryotic cells Eukaryotic Cells surrounding No Nucleus Nucleus some animal No Organelles Organelles cells Cell Wall of If cell wall, Cellulose or Motility Some have Complex Peptidoglycan Chitin flagella undulating Binary Fission Mitosis composed of flagella or cilia 1 Circular chromosome Linear chromosomes filament, hook, composed of and b “9+2” DIFFERENTIAL PROPERTIES OF PROKARYOTIC arrangement of AND EUKARYOTIC CELLS microtubules are present in Characteristics Prokaryotic Eukaryotic some; others Types Bacteria Protists, Fungi, movement of (Monerans) Plants, and amoeboid Animals action Organization Unicellular Usually Flagella Present in Present in Multicellular some some, (Except Yeast technically and Protists) internal Cell Size Small (0.1-10 Larger (10-100 Cillia Absent in all Present in um) um) some Membrane- Absent Present Fimbriae and Present in Absent in all bound Pili some organelles Cell wall Present in Present in Reproduction Asexual Asexual and most; in most; Sexual bacteria, composed of DNA Circular Linear composed of protein, Protein Assoc. Basic Histones peptidoglycan cellulose, algin, with DNA agar, Plasma No sterols Sterols carrageenan, Membrane silicate, Ribosomes 70 S 80 S glucomannan, Cytoskeleton Absent Present or chitin. Cytoplasmic Usually lacks Contains Membrane carbs and glycolipids, COMPARISON OF PROKARYOTIC AND sterols glycoproteins, EUKARYOTIC CELLS and sterols. Characteristics Prokaryotic Eukaryotic Cytosol Present in all Present in all Size 0.2-2.0 um 10-100 um Inclusions Present in most Present in diameter diameter some Nucleus Absent in all Present Endospores Present in Absent in all Free Absent in all Present; ER, some Organelles Golgi bodies, Ribosomes Smaller (70S) Larger (80S) in bound with Lysosomes, cytoplasm (70S phospholipid Mitochondria, in mitochondria membrane Chloroplasts and chloroplast Glycocalyx Present as Chromosomes Single, circular More than 1, organized and lacking linear, and capsule or as histones histones. unorganized  NONMEMBRANOUS AND MEMBRANOUS COMPARISON OF BACTERIAL, ARCHAEAL, ORGANELLES OF CELLS AND EUKARYOTIC CELLS Non-membranous Organelles Ribosomes: Protein Synthesis - Prokaryotes- Present in all - Eukaryotes: Present in all Cytoskeleton: Shape in Prokaryotes; Support, cytoplasmic streaming and endocytosis in eukaryotes - Prokaryotes- Present in some - Eukaryotes – Present in all Centrosomes: Appears to play a role in mitosis, cytokinesis and flagella and cilia formation in animal cells - Prokaryotes- Present in some - Eukaryotes – Present in all Membranous Organelles: Sequester chemical reactions within the cells GENERALIZED STRUCTURE OF PROKARYOTIC CELLS Nucleus: “Control center” of the cells - Prokaryotes- Absent in all - Eukaryotes- Present in all Endoplasmic Reticulum (ER): Transport within the cell - Prokaryotes- Absent in all - Eukaryotes- Present in all Golgi Bodies: Exocytosis, secretion - Prokaryotes- Absent in all - Eukaryotes- Present in some Lysosomes: Breakdown of nutrients, self- destruction of damaged or aged cells - Prokaryotes- Absent in all - Eukaryotes- Present in some Peroxisomes: Neutralization o toxins - Prokaryotes- Absent in all PROKARYOTIC & EUKARYOTIC CELLS: AN - Eukaryotes- Present in some OVERVIEW Vacuoles: Storage Prokaryotes: - Prokaryotes- Absent in all Do not have - Eukaryotes- Present in some membrane Vesicles: Storage, digestion, transport surrounding their DNA - Prokaryotes- Absent in all lack a nucleus - Eukaryotes- Present in all Lack various internal Mitochondria: Aerobic ATP production structures bound with - Prokaryotes- Absent in all phospholipid membr - Eukaryotes- Present in most Are small, ~1.0 µm in Chloroplasts: Photosynthesis diameter - Prokaryotes- Absent in all, though Have a simple infoldings of cytoplasmic membrane called structure photosynthetic lamellae have same Composed of bacteria and archaea function in photosynthetic prokaryotes. - Eukaryotes- Present in plants, algae, and some protozoa  FOUR DIVISIONS OF BACTERIA 1. Division Gracilicutes – gram negative Examples: Proteobacteria (E. coli, Salmonella), Cyanobacteria, Spirochetes 2. Division Firmicutes - gram positive Ex.: Bacillus, Clostridium, Streptococcus 3. Division Tenericutes – without cell wall Ex.: Mycoplasma, Ureaplasma 4. Division Mendosicutes – they lack peptidoglycan in their cell wall and are similar to Archaea/archaebacteria - Ex.:Methanogens, Halophiles, Thermophiles Eukaryotes GRAM POSITIVE CELL WALL Have membrane surrounding their DNA Consists of a thick, homogenous sheath of Have a nucleus peptidoglycan 20-80 nm thick Have internal membranebound organelles tightly bound acidic polysaccharides Are larger, 10-100 µm in diameter including teichoic acid and lipoteichoic acid – cell membrane Have more complex structure Composed of algae, protozoa, fungi, animals, and plants Retain crystal violet and stain purple THE CELL ENVELOPE External covering outside the cytoplasm Composed of two basic layers: –cell wall and cell membrane Maintains cell integrity Two generally different groups of bacteria - demonstrated by Gram stain: - Gram-positive bacteria - Gram-negative bacteria STRUCTURE OF THE CELL WALL - PEPTIDOGLYCAN macromolecule composed of a repeating framework of long glycan chains cross-linked by short peptide fragments provides strong, flexible support to keep bacteria GRAM NEGATIVE CELL WALL from bursting or collapsing because of changes in Consists of an outer membrane containing osmotic pressure lipopolysaccharide (LPS) – thin shell of peptidoglycan – periplasmic space – inner Composition of peptidoglycan (also known as membrane murein Lose crystal violet and stain red from safranin The backbone of the peptidoglycan layer is made of counterstain alternating sugar molecules: N-acetylgluc osamine Protective structure while providing some flexibility (NAG/ GlcNAc) and N-acetylmu ramic acid (NAM/ and sensitivity to lysis MurNAc). These sugars are linked together through β-(1,4)- LPS glycosidi c bonds, forming long bound chain. endotoxin that may become toxic when released The peptide bridge typically contains four amino during infections acids, usually L-alanine, D-glutamic acid, meso- may function as receptors and blocking immune diaminopimelic acid (in Gram-negative bacteria) or response contains porin proteins in upper layer 4 GROUPS BASED ON CELL WALL COMPOSITION Regulates molecules entering and leaving cell 1. Gram positive cells 2. Gram negative cells 3. Bacteria without cell walls 4. Bacteria with chemically unique cell walls  Phospholipid Bilayer Functions: Regulates nutrient and water intake Regulates waste removal Site of prokaryotic respiration Site of prokaryotic flagella attachment Involved in the distribution of genetic material during binary fission. PROKARYOTIC CELL MEMBRANE Structure: Referred to as phospholipid bilayer; composed of lipids and associated proteins Approximately half composed of proteins that act as recognition proteins, enzymes, receptors, carriers, or channels - Integral proteins PROKARYOTIC CELL MEMBRANE - Peripheral Functions: proteins Energy storage - Glycoproteins Harvest light energy in photosynthetic prokaryotes Fluid mosaic model Selectively permeable describes current understanding of membrane Naturally impermeable to most substances structure Proteins allow substances to cross membrane - Occurs by passive or active processes CELL MEMBRANE Maintain concentration and electrical gradient Membranes contain a hydrophilic and hydrophobic - Chemicals concentrated on one side of the side membrane or the other Composed of many different types of proteins - Voltage exists across the membrane. Proteins in the lipid bilayer move freely within the membrane Thin pliable lipid and protein envelope that defines a cell.  EXTERNAL STRUCTURES OF PROKARYOTIC Sticky layer that allows prokaryotes to attach to CELLS surfaces GLYCOCALYCES Functions: Gelatinous, sticky substance surrounding the Protection outside of the cell Attachment Composed of polysaccharides, polypeptides, or Associated with biofilms both BACTERIAL APPENDAGES Flagella Axial Filaments (Endoflagella) Pili Fimbriae Many bacteria have fine, hairlike appendages that are thinner and typically shorter than flagella. These are usually called fimbriae (s., fimbria) or pili (s., pilus) EXTERNAL STRUCTURTES - FLAGELLA Structures of locmotion Originate in the plasma membrane In bacteria, rotate like a propellar Many different The Bacterial Surface arrangements Coating - Glycocalyx Are responsible for Two types: movement 1. Capsule - highly Have long structures that extend beyond cell organized, surface tightly attached Are not present on all prokaryotes 2. Slime layer - Cell Extensions - The Flagella loosely organized and attached Types of Glycocalyces 1. Capsule Composed of organized repeating units of organic chemicals Firmly attached to cell surface Protects cells from drying out May prevent bacteria from being recognized and destroyed by host. Polysaccharides or polypeptides in composition. Surround the cell wall in some bacteria. Function: Protection from phagocytosis Osmotic barrier Reservoir for nutrients Three Parts: 1. Filament Virulence factor 2. Slime Layer long, thin, helical structure composed of proteins 2. Hook Consist of polysaccharide fibers that extend form the bacterial surface. curved sheath 3. Basal body Loosely attached to cell surface stack of rings firmly anchored in cell wall Water soluble rotates 360 degrees Protects cells from drying out  1-2 or many distributed over entire cell As the endoflagella functions in motility rotate to move the cell the Structure characteristic Composed of filament, hook, and basal body shape is formed Flagellin protein (filament) deposited in a helix at the Endoflagella are lengthening tip associated with Base of filament inserts into hook spirochetes. Basal body anchors filament and hook to cell wall Endoflagellum is by a rod and a series of either two or four rings of also know as an axial filament. integral proteins Attached to the plasma embrane and transverses Filament capable of rotating the entire cell. Arrangements of Responsible for the spirochete morphology. Flagella Polar - flagella are attached at one or both ends of the cell Monotrichous - a single flagellum at one end Lophotrichous - multiple flagella arising from one or both ends Amphitrichous – a single flagellum arises from each end Peritrichous - flagella are randomly dispersed over BACTERIAL APPENDAGES - FIMBRIAE AND PILI the cell surface Rod-like proteinaceous extensions Hollow tubes that protrude A. Monotrichous from some bacteria B. Lophotrichous Compose of protein – C. Amphitrichous fimbrin D. Peritrichous FIMBRIAE Sticky, bristle like projections Used by bacteria to adhere to one another, to Function of Flagella hosts, and to substances in environment Rotation propels bacterium through environment Shorter than Rotation reversible, can be clockwise or flagella counterclockwise May be hundreds Bacteria move in response to stimuli (taxis) per cell - Runs Serve an important - Tumbles function in biofilms Virulence factor AXIAL FILAMENTS (ENDOFLAGELLA) Originates in the cell membrane and transverses PILI the length of the cell in the periplasmic space. Tubules composed of pilin Also known as conjugation pili Longer than fimbriae but shorter than flagella Bacteria typically only have one or two per cell Mediate the transfer of DNA from one cell to another  BACTERIAL CONJUGATION BINARY FISSION Transfer of plasmid DNA from a donor to a - cell division in prokaryotic cell A diagram of the recipient. attachment of bacterial chromosomes, indicating Process strengthens the bacterial cell and alows the possible role of the mesosome (an inward fold for survival in a competitive environment. of the cell membrane) in ensuring the distribution of the "chromosomes" in a dividing cell. - Upon attachment to the plasma membrane, the DNA replicates and reattaches at separate points. Continued growth of the cell gradually separates the chromosomes and allocates chromosome copies to the two daughter cells. Bacterial Ribosomes Ribosomes are the site of protein synthesis, and large numbers of BACTERIAL INCLUSION BODIES them are found in 1. Poly-Beta-Hydroxybutyric Acid - stores lipids for nearly all cells use in plasma membrane 2. Glycogen - stores starch like polymer of sugar for energy production NUCLEOID 3. Polyphosphate Granules (Metachromatic Nucleoid is an irregularly shaped region that Granules) - storage for phosphates for plasma contains the cell's chromosome and numerous membrane and the formation of ATP from ADP. proteins 4. Sulfur Granules - stores sulfur which is necessary Bacterial cells contain ONE chromosome for the metabolic reactions in biosynthesis. Circular in structure - of genetic material during binary fission. Just DNA, no associated proteins 5. Gas Vacuoles - storage of metabolic gases such Bacterial chromosomes are longer than the length as methane or hydrogen gas. The gas vacuoles of the cell. help in the buoyancy of the cell and aids in its Some cells contain PLASMIDS motility. Plasmids are separate from the main chromosome 6. Carboxysomes - present in many cyanobacteria Also circular in structure, but smaller and other C02-fixing bacteria stores; serves as a Contain only a few genes (less than 30). site for C02 fixation. 7. Magnetosomes - Aquatic magnetotactic bacteria NUCLEAR AREA use magnetosomes to orient themselves in Earth's Bacterial cells contain ONE chromosome magnetic field Circular in structure Just DNA, no associated proteins MESOSOMES Some cells contain PLASMIDS - invagination of the Plasmids are separate from the main chromosome plasma membrane that Also circular in structure, but smaller increases the surfaces Contain only a few genes area of the plasma Often carry genes for antibiotic resistance membrane during binary fission. CHROMOSOME - also serves as a site for single, circular, double-stranded DNA molecule the attachment and contains all the genetic information required by a distribution of genetic cell material during binary DNA is tightly coiled around a protein fission. dense area called the nucleoid - considered analogous to the cristae in mitochondria of eukaryotic cells, enhancing the surface area for metabolic activates  PLASMIDS small circular, double-stranded DNA self-replicating extrachromosomal DNA free or integrated into the chromosome duplicated and passed on to offspring not essential to bacterial growth & metabolism may encode antibiotic resistance, tolerance to toxic metals, enzymes & toxins used in genetic engineering- readily manipulated & transferred from cell to cell Have a 2-phase life cycle small fragments of self-replicating - Vegetative cell extrachromosomal DNA that codes for the - Endospore resistance to antibiotics or for the productions of a specific metabolite, i.e., toxins, pigments. These Sporulation plasmids may be transferred from one bacterial cell - formation of to another by the F-pili. endospores Germination - return to vegetative growth - withstand extremes in heat, drying, freezing, radiation & chemicals. The endospores may remain dormant for many years until the environment becomes suitable to sustain the life of the bacteria. The endospore will then germinate to form an exact copy of the parent cell that produced it. These plasmids may be transferred from one bacterial cell to another by the F-pili Endospores resistance linked to high levels of calcium & certain acids longevity verges on immortality – 25 to 250 million years pressurized steam at 120oC for 20-30 minutes will destroy endospores 10. Endospores - a survival mechanism of certain genera of bacteria such as Clostridium and Bacillus. - The endospores are composed of a complex of dipicolinc acid and calcium and the function of the endospore is to protect the bacterial chromosome. - are very resistant to heat, desiccation, freezing, and other physical properties such as pesticides, antibiotics, dyes, and acids. - resting, dormant cells - produced by some G+ genera o Clostridium, Bacillus & Sporosarcina  EXTERNAL STRUCTURE OF EUKARYOTIC Function CELLS Do not rotate, but undulate rhythmically EUKARYOTIC CELL WALLS & CYTOPLASMIC MEMBRANES Fungi, algae, plants, and some protozoa have cell walls but no glycocalyx Composed of various polysaccharides - Cellulose found in plant cell walls - Fungal cell walls composed of cellulose, chitin, and/or glucomannan - Algal cell walls EUKARYOTIC APPENDAGES; CILIA composed of CILIA cellulose, Similar to flagella both structurally and functionally proteins, agar, but are much shorter and more numerous. carrageenan, Cilia are silicates, algin, calcium carbonate, or a found combination of these. peritrichously CELL WALLS to the cell. Three different types of cell walls and their Move in an compositions: undulating Fungal cell walls are composed of cellulose and/or manner and chitin. motility by Plant cell walls are composed of cellulose. those organisms with cilia is much more rapid than Algal cell walls are composed of cellulose, silicon, those with flagella. and calcium carbonate INTRACELLULAR STRUCTURES OF PLASMA MEMBRANE EUKARYOTIC ORGANISMS (ORGANELLES) Consist of a lipid bilayer and associated proteins. MEMBRANOUS ORGANELLES: NUCLEUS PM of Eukaryotic cells resembles and functions in NUCLEUS: the same manner as the prokaryotic plasma Often largest organelle in cell membrane with the following exceptions; Contains most of the cell’s DNA Contains high levels of sterols such as cholesterol. Semi-liquid portion called nucleoplasm No respiratory enzymes located in the eukaryotic One or more nucleoli present in nucleoplasm; plasma membrane. RNA synthesized in nucleoli Respiration occurs in the mitochondria Nucleoplasm contains chromatin - masses of DNA associated with histones. GLYCOCALYCES Surrounded by nuclear envelope Never as organized as prokaryotic capsules - double membrane composed of two Help anchor animal cells to each other phospholipid bilayers Strengthen cell surface Nuclear envelope contains nuclear pores. Provide protection against dehydration Function in cell-to-cell recognition and communication. EUKARYOTIC APPENDAGES; FLAGELLA Flagella There are several different arrangements of flagella in eucaryotes. This diagram represents a biflagellated eukaryotic cell. One of the flagella aids in movement laterally and the other aids in up and down movement. The eukaryotic flagella move like a whip.  MEMBRANOUS ORGANELLES: ENDOPLASMIC It modifies and packages the lipids and proteins RETICULUM manufactured by the ER and places them in ENDOPLASMIC vesicles for cellular use RETICULUM MEMBRANOUS ORGANELLES: LYSOSOMES, Netlike arrangement PEROXISOMES, VACUOLES, AND VESICLES of flattened, hollow Store and transfer chemicals within cells tubules continuous May store nutrients in cell with nuclear Lysosomes contain catabolic enzymes envelope Peroxisomes contain enzymes that degrade Functions as poisonous wastes transport system network of cytoplasmic membranes where lipids and proteins are produced. Two forms: 1. SMOOTH ENDOPLASMIC RETICULUM (SER) – plays role in lipid synthesis. 2. ROUGH ENDOPLASMIC RETICULUM (RER) – ribosomes attached to its outer surface; transports proteins produced by ribosomes. - associated with ribosomes and is responsible for the synthesis of proteins. MEMBRANOUS ORGANELLES: MITOCHONDRIA MITOCHODRIA Have two membranes composed of phospholipid bilayer Produce most of cell’s ATP MEMBRANOUS ORGANELLES: GOLGI BODY Interior matrix contains 70S ribosomes and GOLGI BODY circular molecule of DNA Receives, processes, and packages large Involved in the production of chemical energy in molecules for export from cell the form of ATP. Packages molecules in secretory vesicles that fuse Consist of convoluted inner membrane and outer with cytoplasmic membrane membrane. Invaginations are called cristae and Composed of flattened hollow sacs surrounded by contain enzymes used to synthesis ATP. phospholipid bilayer All respiratory enzymes are located in the inner Not in all eukaryotic cells membrane of the mitochondria. Golgi apparatus (dictyosome) is associated with the MEMBRANOUS ORGANELLES: ER. CHLOROPLASTS Light-harvesting structures found in photosynthetic eukaryotes  Have two phospholipid bilayer membranes and DNA Have 70S ribosomes