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microbiology
quiz 2
| Question | Answer |
|---|---|
| light microscope | (external structure) |
| electron microscope | (internal structure) |
| Isolation of cell components | fractionation, ultracentrifugation |
| SIMILARITIES PROKARYOTIC & EUKARYOTIC CELLS | COMPOSED OF THE SAME 4 BASIC BIOLOGICAL MACROMOLECULES • UNDERGO THE SAME TYPES CHEMICAL REACTIONS • DISPLAY THE SAME CHARACTERISTICS OF LIVING ORGANISMS |
| DIFFERENCES:PROKARYOTIC & EUKARYOTIC CELLS | AMOUNTS OF BASIC MACROMOLECULES • REACTANTS DIFFER SO END PRODUCTS OF REACTIONS DIFFER • LIVE IN A GREATER VARIETY OF ECOLOGICAL NICHES • EXHIBIT GREATER VARIETY IN THEIR BIOCHEMICAL CAPABILITIES |
| Nucleus | prokaryote has no nucleus eukaryotic has a nucleus |
| genetic material | prokaryotic have One circular DNA molecule, eukaryotic have chromosomes packed with proteins |
| Ribosomes | prokaryotic have 70s ribosomes, eukarytic have 80s |
| cell wall | prokaryotic cells have a cell wall made of peptidoglycan, plant cell wall of cellulose, fungus cell wall of chitin |
| membrane | no sterols in prokaryotic, sterols in eukaryotic. sterols allow fluidity |
| Membrane bound Organelles | no membrane bound organelles in prokaryote, membrane bound organelles in eukaryote. |
| Organisms | prokaryotic cells are bacteria and archea eukaryotic cells are Animals, Plants Fungi, Protozoa, Algae |
| Reproduction | prokaryotic cells reproduce asexually via binary fusion eukaryotic cells reproduce asexually or sexually |
| coccus, cocci | Spherical or round shaped bacteria |
| bacillus, bacilli | Rod shaped shaped bacteria |
| spirochete | Corkscrew shaped bacteria, flexible, moves via axio filaments |
| spirillum, spirilla | loose S shaped bacteria, rigid shaped, moves via polar flagella |
| vibrio | Comma shaped |
| coccus | Single coccus |
| Diplococci | coccus in pairs |
| Streptococci | coccus in chains |
| Tetrads | coccus in groups of four |
| Sarcina | coccus in cubical packets |
| Staphylococci | coccus in irregular cluster |
| Diplobacilli | Bacilli in pairs |
| Streptobacilli | Bacilli in chains |
| Pleomorphism | Variation in cell shape and size within a single species, could happen because of Nutritional /hereditary differences |
| Bacterial Appendages | Motility– flagella and axial filaments Attachment or channels– fimbriae, pili |
| Glycocalyx | surface coating of molecules external to the cell wall, made of polysaccharides/or polyproteins SIGNIFICANCE: INCREASE PATHOGENICITY |
| Filament | ong, thin, helical structure composed of protein flagellin |
| Hook | curved sheath |
| Basal body | stack of rings firmly anchored in cell wall |
| Flagellar Mechanism of Action | • Rotates 360 |
| Monotrichous | single flagellum at one end |
| Lophotrichous | small bunches (tufts) emerging from the same site |
| Amphitrichous | flagella at both ends of cell |
| Peritrichous | flagella dispersed over surface of cell coming from all sides |
| chemotaxis | positive and negative Chemical stimuli |
| phototaxis | Light stimuli |
| run motion | flagella rotaes Counterclockwise |
| tumbles motion | flagella rotates clockise |
| FIMBRIAE & PILI | COMPOSITION: protein pilin • FUNCTION: attachment; transfer of DNA • SIGNIFICANCE: increase pathogenicity or virulence |
| Pili | Rigid tubular structure made of pilin protein • Found only in gram-negative cells • Function to join bacterial cells for partial DNA transfer called conjugation (horizontal gene transfer) (sex bridge) causes deadly bacteria to multiply quickly |
| Fimbriae (fimbria) | Fine, proteinaceous, hairlike bristles emerging from the cell surface ( Pilin) • Function in adhesion to other cells and surface |
| Slime layer Glycocalyx | loosely organized and attached; easily washed off |
| Capsule Glycocalyx | highly organized, tightly attached; thick; not readily |
| Functions of the Glycocalyx | • Protect cells from dehydration and nutrient loss • Protect cells from toxic chemicals (antibiotics, disinfectants) •can evade phagocytosis, contributing to pathogenicity • Attachment - formation of biofilms |
| Gram-positive bacteria | thick cell wall composed primarily of peptidoglycan and cell membrane, very little space, includes techoic acid |
| Gram-negative bacteria | outer cell membrane, thin peptidoglycan layer, and cell membrane, lots of space and lps |
| Function of Cell Walls | -Determines cell shape - Prevents lysis due to changing osmotic pressures |
| Composition of Cell Walls | -Peptidoglycan is the primary component: – Unique to prokaryotes in Domain Bacteria – Macromolecule composed of a repeating framework of long glycan chains cross-linked by short peptide fragments |
| NEGATIVE STAIN | *Capsule does not take stain, so you Use simple acidic stain to color the background |
| Basic stain | color is in the positive ion because the cell wall is made up of negative ions a basic stain will stain the cell wall |
| acidic stain | color is in the negative ion because the cell wall is made up of negative ions a negative stain will stain the background not the cell wall |
| Gram-Positive Cell Wall | one layer composed of peptidoglycan, teichoic acid, lipoteichoic acid thicker than gram negative no outer membrane narrow periplasmic space more penetrable |
| Gram-Negative Cell Wall | two layer composed of lipopolysaccharides (LPS), porin proteins, peptidoglycan, Lipoproteins thinner than gram positive has an outermembrane large periplasmic space less penetrable than gram positive |
| GRAM STAIN PROCEDURE | A differential staining procedure positive ion will retain primary stain (if primary stain is orange then the positive ion cell wall will turn orange negative ion retains the opposite color |
| GRAM STAIN PROCEDURE (steps) | Apply Crystal Violet (primary dye), all cell walls will be stained. apply Gram’s iodine (mordant) apply Alcohol (decolorizer) apply Safranin (red dye counterstain) gram positive will be purple gram negative will be red |
| exotoxins | made of protein, produced inside gram positive cells, then secreted out into the blood to target specific organs |
| endotoxins | produced inside gram negative cells, are contained inside the cell until the cell dies, when cell dies the toxins are released due to the destruction of the cell wall, toxin will have a general effect on the body |
Created by:
Virajasaur
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