MGY377H1 Final: Study notes for exam

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redtermite204

27 Dec 2011

School

UTSG

Department

Molecular Genetics and Microbiology

Course

MGY377H1

Professor

William Navarre

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Document Summary

In various ways: flagella based, gliding motility, twitching motility. Access new environments: for survival, for pathogenesis. Drive by surface appendages: flagella, pili. Most motile bacteria use flagella: movement in liquid, and on moist surfaces. Helically shaped: constant distance between curves, called wavelength, wavelength constant for given organism. Distribution varies: polar one per cell, peritrichous multiple per cell all around cell, lophotrichous multiple per cell but stem from one end only. Structure: filament rigid, helical structure extending from basal body. composed of protein flagellin, arranged in helical chains to form hollow core. flagellin travels through hollow core of filament to be attached at the growing tip. cap proteins help assemble flagellin into growing tip of flagella: hook. flexible coupling between filament and basal body: basal body. rod and a series of rings that anchor the flagellum to cell. Motility: driven by proton motive force. as protons travel through channel creates energy.

Related Questions

I need help answering a question regarding a lab experiement, the experiment is this:

Certain species (not all) of bacteria have ability to propel themselves with the use of the whip-like flagella. The ability to move in a specific direction is called taxis. When bacteria move towards advantageous stimuli (food or light) this is known as positive taxis. When they move away from harmful stimuli (toxins or antibiotics) it is known as negative taxis.

Not all bacteria that possess flagella have the same number. Bacteria with one flagellum are called monotrichous. Bacteria with flagella at either end are called amphitrichous. Bacteria with flagella all over them are called peritrichous.

In order to test for motility (presence of flagella), a special semi-solid media is used (0.4% rather than 1.5%). We will use an inoculating needle to stab the bacteria into the media. Motile bacteria will grow outward from the stab mark.

I need help answering this first question regarding the lab info given. Question:

Why is it important to use proper aseptic technique for this test?

4. In addition to their use in motility, flagella can also be used to sense when the bacterial cell comes in contact with a surface.

A. How are flagella used in motility? How does a bacterium move toward a nutrient source using flagella?

B. Now itâs time to think at the molecular size and do some visualization. Youâre standing on a bacterial cell membrane watching ions flow and flagella turn. All of a sudden, the cell runs into a surface, and the flagella stop turning. What will happen (immediately) to the PMF? Describe two ways the cell (in the next few moments) could compensate for this? As the cell compensates, how will its oxygen consumption be altered? Its ATP production?

C. Instead of the compensations you mentioned above, some bacteria have the ability to produce a special protein that acts to increase the distance between the flagellar rotor and stator so that this distance is much larger than a hydrogen ion. Explain how this protein will affect the PMF and the rotation of the flagella.

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The return of motility is sudden. What does this suggest aboutflagellar function in these organisms?

What was the length of the flagella when normal motilityreturned to the deflagellated organisms (um)?

What percentage of the length in controls must be attainedbefore normal motility returns?

What is the mean rate of flagellar regeneration in Chlamydomonas(um/min)?

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MGY377H1 Final: Study notes for exam

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