MICRO 3050 Exam 2 QUESTIONS AND ANSWERS WITH COMPLETE SOLUTIONS GRADED A++

MICRO 3050 Exam 2 QUESTIONS AND ANSWERS WITH COMPLETE SOLUTIONS GRADED A++ 5.0 (1 review) Practice questions for this set Terms in this set (107) (Bacterial)Endospores A complex, dormant, survival structure that is formed by some bacteria (usually gram positive bacteria that live underground) (location within the cell is species specific). Useful because these structures are RESISTANT to: heat, radiation, chemicals, and desiccation(drying out) and therefore can like for 1000s of years in their dormant form. Exosporium Part of endospore structure, the most outer layer that is composed of proteins. Spore Coat Part of endospore structure, the multiple layers of protein that are impermeable to toxins. Cortex Another layer of protection around an endospore, composed of peptidoglycan that is less cross-linked than in normal cell walls. Core The innermost part of an endospore, this contains the cytoplasm and all the essentials of a cell (similar to the interior of a bacterial cell with a FEW differences. Germ Cell Wall A part of the endospore that is also made of peptidoglycan, becomes the cell wall when the bacterim emerges (when germination occurs the protective outer layers are lost). Gliding A type of bacterial motility, smooth movements that may involve a pili and/or slime. Twitching A type of bacterial motility that occurs when pili are at the ends of the cell and cells are in contact with each other and with a surface. Appears as short, intermittent, jerky motions. Spirochete A type of bacterial motility that exhibits flexing and spinning movements. Caused by multiple flagella forming an axial fibril which then winds around the cell itself. The flagella all remain in the periplasmic space found right inside the outer sheath. Chemotaxis, chemo Movement towards a chemical attractant OR away from a chemical repellent. The ______attractants and ____repellants are dectected by receptors on the surfaces of cells. A complex BUT rapid process (response in less than 20 milliseconds). Run, tumble(lower frequency of tumbles) If a bacteria senses a POSITIVE chemotaxis, it will ______ more and less. Tumble, run If a bacteria's chemoreceptors sense a chemorepellant then the bacteria will _______ more and less. Flagellum Threadlike appendages found extending outward from the plasma membrane and cell wall of bacteria. Functions: -Motility and Swarming behavior (all going one place) -Attachment/burrowing to surfaces -Virulence factor(in some cases) Peritrichous A pattern of flagella distribution, spread over entire surface of cell (peri= perimeter). Lopotrichous A pattern of flagella distribution, a cluster of flagella at one or BOTH ends of the bacteria. Amphitrichous A pattern of flagella distribution; ONE flagellum (not a cluster) at each end of the cell. Polar Flagellum Pattern of flagella distribution; flagellum are found only at ONE END of the cell. Monotrichous A pattern of flagella distribution; describes a cell with only one flagellum on it.