Daily Newsletter January 20, 2012
Today's Topic: Bacterial Flagella and Chemotaxis
An important topic in microbiology is the study of the flagella, as it is used for locomotion and attachment. Attachment? As we move through the semester, you will find that the topic of whether a cell is free swimming or attached is critical. For medical microbiology, we find that pathogens must first be able to attache to their host before the an infectious process begins (it is the critical step).
The bacterial flagella is also different from the Eukaryotic flagella, and uses a different power source. You will hear me say throughout the semester that Bacteria have a different ATP yield than Eukaryotic cells from catabolism (e.g., the breakdown of glucose). One reason for this is that bacteria will use a proton motive force instead of ATP for some functions. Flagellar movement is one of those functions. The proton motive pump is used instead of ATP to get flagella spinning.
Spinning? Unlike eukaryotic flagella, which have a whip like motion, bacterial flagella rotate. Further, they can rotate either clockwise or counterclockwise. You can also have multiple flagella, and there are specific arrangements of flagella. Why is all this important? Consider why bacteria want to be motile...to move toward nutrient, or away from toxins (chemotaxis).
Also consider, for chemotaxis to work, bacterial cells must have a receptor that picks up the chemical signal.
Daily Challenge:
Today you are to discuss the flagella, its movement and chemotaxis. Pull in images to help explain the flagella. Do not rely solely on images. You need to verbally discuss. As you move through this challenge, keep in mind why the flagella is important. What advantage does it give the cell?
An important topic in microbiology is the study of the flagella, as it is used for locomotion and attachment. Attachment? As we move through the semester, you will find that the topic of whether a cell is free swimming or attached is critical. For medical microbiology, we find that pathogens must first be able to attache to their host before the an infectious process begins (it is the critical step).
The bacterial flagella is also different from the Eukaryotic flagella, and uses a different power source. You will hear me say throughout the semester that Bacteria have a different ATP yield than Eukaryotic cells from catabolism (e.g., the breakdown of glucose). One reason for this is that bacteria will use a proton motive force instead of ATP for some functions. Flagellar movement is one of those functions. The proton motive pump is used instead of ATP to get flagella spinning.
Spinning? Unlike eukaryotic flagella, which have a whip like motion, bacterial flagella rotate. Further, they can rotate either clockwise or counterclockwise. You can also have multiple flagella, and there are specific arrangements of flagella. Why is all this important? Consider why bacteria want to be motile...to move toward nutrient, or away from toxins (chemotaxis).
Also consider, for chemotaxis to work, bacterial cells must have a receptor that picks up the chemical signal.
Daily Challenge:
Today you are to discuss the flagella, its movement and chemotaxis. Pull in images to help explain the flagella. Do not rely solely on images. You need to verbally discuss. As you move through this challenge, keep in mind why the flagella is important. What advantage does it give the cell?
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