Chapter 4 – Prokaryotic Profiles – The Bacteria and Archae – Flashcards
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| What are structures common to all bacterial cells? |
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| Cell membrane, cytoplasm and ribosomes. |
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| What are Ribosomes function? |
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| Produce proteins. NOT AN ORGANELLE (DNA, RNA, protein) |
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| What are structures found in MOST bacterial cells? |
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| Cell wall (very small #), Surface coating or glycocalyx |
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| What are structures found in SOME bacterial cells? |
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| Flagella, pili, fimbriae, capsules, slime layers, inclusions, actin cytoskeleton, endospores. |
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| What is a "capsule"? |
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| Outershell/coating. Solid. |
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| What is an inclusion? |
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| Internal clusters of stuff for storage of nutrients. |
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| Why don't bacteria need an actin cytoskeleton? |
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| Because of their cell wall. |
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| How many genus of bacteria produce spore? |
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| 3. |
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| Why aren't all of these structures in all bacteria? |
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| If something is not useful, a bacteria will quickly evolve to get rid of it. |
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| Are appendages common in all species? |
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| No. |
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| What do appendages provide? |
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| motility. |
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| What else are appendages used for? |
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| Attachment, mating. |
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| How does mating occur? |
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| They exchange genetic material NOT sexually. |
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| What are the three parts of a flagella? |
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| Filament, hook (sheath), and basal body. |
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| What is the filament? |
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| A whip-like helical structure that generates movement. |
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| What is the hook? |
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| Holds the filament. Attached to the rod portion of the basal body. |
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| What is the basal body? What does it consist of? |
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| The motor. A complex structure consisting of a rod, 4 rings and a motor contained within the cell envelope. |
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| What is the cell envelope? |
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| The cell membrane + wall and everything collectively. Gel-like substance. |
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| What does activation of the motor cause? |
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| The hook/filament to swivel. AKA movement. It rotates clockwise and counterclockwise. |
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| What does Monotrichous mean? |
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| Single flagellum |
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| What does lophotrichous mean? |
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| Small bunches/tufts of flagella emerging from the SAME site. |
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| What does amphitrichous mean? |
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| Flagella attached to BOTH ends/poles of the cell. |
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| What does peritrichous mean? |
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| Flagella dispersed randomly all over the cell. |
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| What does the flagella function in? |
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| Chemotaxis - movement of the cell in response to a chemical signal. |
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| What are the 2 types of chemotaxis? |
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| Positive - towards. Negative - away. |
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| What is phototaxis? |
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| Movement towards light. |
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| How is movement achieved with flaggela? |
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| Runs + tumbles. |
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| What are runs? |
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| Linear movement. |
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| What are tumbles? |
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| "Period of assessment" cell stops and reverses directions or spins in place. |
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| How is a tumble created? |
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| Clockwise flagellar rotation starting Right. |
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| What are axial filaments? |
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| Periplasmic flagella |
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| Where are periplasmic filaments found? |
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| A special group of bacteria known as Spirochetes AKA syphilis. |
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| What does a periplasmic filament consist of? Where is it located? |
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| A filament and hook but the entire structure is located between the celll wall and membrane. |
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| What is the area between the cell wall and membrane known as? |
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| The periplasmic space. |
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| How does a P.F. create movement? |
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| Through twisting and flexing actions. |
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| What is a Pili? |
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| Elongated, rigid hollow structure |
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| On what type of bacteria is it sometimes found? |
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| Gram-negative bacteria. |
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| What are Pili involved in? |
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| Attachment, movement and conjugation. Exchange of genetic material |
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| What is Fimbriae? |
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| Small bristle-like fibers. Plaque on your teeth. |
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| What do Fimbriae tend to stick to? |
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| Each other and to surfaces. |
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| What is Glycocalyx? |
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| A sticky "sugar" coating. |
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| What does Glycocalyx develop as? |
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| A coating of repeating polysaccharide units, protein or both. |
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| They differ among bacteria in ______, ______ and _______ ________. |
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| Thickness, organization and chemical composition. |
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| What is the slime layer? |
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| A loose shield that protects some bacteria from loss of water or nutrients. Differs in thickness in different areas |
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| What is a capsule? |
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| When the glycocalyx is bound more tightly to the cell and is denser and thicker. Pneumonia. |
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| What are the functions of Glycocalyx? |
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| 1.)Protects the cell -Formed by many pathogenic bacteria to protect bacteria against phagocytes 2.)Sometimes helps cell adhere to environment -Biofilms (plaque) 3.)Helps prevent the loss of water or nutrients |
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| Does Glycocalyx function in regulation? |
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| NO. That is the cell membrane's job! |
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| What are the basic 3 layers of the cell envelope? |
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| The cell wall (inner), the cell membrane (outer) and in some bacteria the outer membrane (outermost) |
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| If a cell is Gram-Negative, does it have an outer membrane or no? |
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| Yes, it has an outer membrane. |
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| What does a gram-positive cell possess? |
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| A physically stronger membrane. Two layers - 1.)cell wall 2.)cell membrane |
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| What does a gram-negative cell possess? |
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| A more durable/physiologically stronger membrane. 3 Layers - 1.)Outer membrane 2.)Cell Wall 3.)Cell Membrane |
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| The structure of the cell wall helps to determine the ______ of the bacterium. |
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| Shape. |
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| What does the cell wall provide the cell with? |
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| Strong structural support. |
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| Why are most cell walls rigid? |
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| Peptidoglycan. All domain bacteria have this. |
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| The cell wall keeps the cell from ______ because of changes in pressure due to _______. |
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| rupturing (lysis)/osmosis. |
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| The cell wall is the target of many antibiotics. T or F? |
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| T |
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| Is the gram-positive wall thinner or thicker than negative? |
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| Thicker. |
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| Is there a lot or a little room in between the cell wall and membrane? |
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| A little. Very narrow. |
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| What 2 molecules are commonly found in Gram-Positive cell walls? |
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| Teichoic acid & Lipoteichoic acid. |
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| What is techoic acid? |
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| Binds together layers or peptidoglycan. |
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| What is lipoteichoic acid? |
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| Links the peptidoglycan layers to the lipid cell membrane. |
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| Gram-positive cells are ____ susceptible to lysis but ______ permeable than gram-negative bacteria. |
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| less/more |
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| Gram-Negative cell walls have a wide or narrow periplasmic space? |
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| Wide. |
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| What is the LPS layer? |
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| Similar to the cell membrane except it contains specialized polysaccharides and proteins. |
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| What is the innermost layer of Gram-Neg bacteria? |
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| A phospholipid layer anchored by lipoproteins to the peptidoglycan layer below. |
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| What is the outermost layer of the LPS? |
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| Contains lipopolysaccharide with two important components: Lipid A/O-Specific Polysaccharide |
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| What is Lipid A? |
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| Found within the bilayer, recognized by our immune systems. |
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| What is O-Specific Polysaccaride? |
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| Found externally, used to identify certain strains/species of bacteria (E Coli) |
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| What does the outer membrane of Gram-Neg bacter serve as? |
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| Partial chemical sieve. REGULATION. Only small molecules can penetrate. |
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| Gram-Neg bacteria are _____ permeable because of LPS but ____ susceptible to lysis than gram-pos bacteria. |
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| less/more |
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| What is the cell membrane also known as? |
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| The cytoplasmic membrane or plasma membrane. |
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| What does the cell membrane primarily contain? |
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| Phospholipids and proteins. |
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| What are the functions of the cell membrane? |
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| 1.)Provides site for functions -energy rxn, nutrient processing, synthesis. 2.)Regulates transport -selectively permeable (main fxn) 3.)Secretion |
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| What are the contents of cell cytoplasm of Bacteria? |
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| Gelatinous soultion, Chromatin body, Plasmids, Ribosomes, Inclusions, Actin Cytoskeleton. |
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| The gelatinous solution is the site for many biochemical and synthetic activities. T or F? |
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| T |
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| Gelatinous soultion is ____ - 80% water. |
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| 70 |
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| What is the chromatin body? |
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| A collection of DNA. Single, circular strand of essential DNA. |
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| Where is the chromatin body? |
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| The nucleoid. No membrane around it. A DENSE area of the cell. |
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| Are plasmids essential? |
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| No, but are helpful! |
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| Where are plasmids found? |
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| Floating in cytoplasm or attached to chromatin body. |
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| What do plasmids often confer? |
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| Protective traits (drug resistance or production of toxins/enzymes) |
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| Can plasmids be transferred to one bacterium to another? |
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| Yes, thereby transferring traits it carries. |
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| What do ribosomes do? |
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| PRODUCE PROTEINS |
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| What are Ribosomes made of? |
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| rRNA and protein |
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| What are Ribosomes characterized by? |
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| S-units. The prokaryotic ribosome is 70S |
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| What are inclusions? |
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| Storehouse for nutrients. Stored there when abundant, taken from there when depleted. |
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| Aquatic bacteria use inclusions to hold gas for what? |
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| Buoyancy. |
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| What is the actin cytoskeleton? |
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| Long polymers of actin that contribute to cell shape. (not as much as cell wall) |
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| What are dormant bodies? |
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| Produced by Bacillus, Clostridium and Sporosarcina. ALL GRAM POSITIVE RODS. |
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| How many life stages do these bacteria have? |
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| 2. Vegetative & Endospore |
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| What happens during the Vegetative cell phase? |
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| They are metabolically/actively growing. Can be induced by the environment to undergo spore formation AKA sporulation. |
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| What happens during the Endospore phase? |
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| Cell must be stimulated by the depletion of nutrients.(Temp/h20..) Process takes 6-8 hours (30-45 mins for bacteria) Vegetative cell changes to a sporangium. DNA is replicated. A septum forms dividing the cell unequally. The larger portion engulfs the smaller resulting in a FORESPORE. A thick peptidoglycan coat forms around forespore. Now is an endospore. |
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| The endospore remains dormant until the conidtions improve around it. There are some endospores as old as 250 million years old. T or F? |
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| T. |
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| Is this process reversible? |
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| NO. |
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| Can Endospores withstand extremes in heat, drying freezing, radiation and chemicals? |
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| Yes |
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| What is Germination? |
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| The breaking of Endospore dormancy. |
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| In the presence of _____ and a specific ________ agent, the spore will break down and a vegetative cell will develop rapidly. |
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| water/germination |
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| Are most endospores harmless to human health? |
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| Yes. |
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| What is one example of bacteria that depend on spores? |
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| Bacillus antracis. |
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| What are the three general shapes of bacteria? |
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| 1.)Coccus - sphereical 2.)Bacillus - rod-shaped 3.)Spirillium - curviform/spiral |
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| What are the two subcategories of bacillus? |
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| Coccobaccilus - short and plump like football Vibrio - gently curved like boomerang |
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| What does pleomorphism mean? |
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| When cells of a single species vary to some extent in size and shape. Ex: e coli |
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| Which shape of bacteria has the most variety in arrangement? |
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| Cocci |
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| What are the 6 arrangement possibilities of Cocci? |
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| 1.)Singles- isolated. uncommon 2.)Pairs (diplococcic)- pneumonia 3.)Tetrads- group of 4 non-chain square 4.)Irregular clusters (staphylococci)- grape-like structure 5.)Chains (streptococci)- B.Sub 6.)Cubical packet (sarcina)- cube 3-d |
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| What are the 4 arrangement possibilities of Bacillus? |
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| 1.)Singles 2.)Pairs 3.)Chain 4.)Row of cells oriented side by side (Lincoln logs) |
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| What are the 2 arrangement possibilities of Spirilla? |
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| 1.)Usually SINGLES 2.)Occasional Short Chain |
