Micro biology?

Question

1-describe how motility medium demonstrates motility?

2-compare difference between the flagella of prokaryotic and eukaryotic organisme?

3-Discuss how periplasmic flagella and gliding motility provide locomotion for bacteria? Thanks

Answer 1

I agree except on question 1.  Motility medium, usually a semi-solid, is used to inject a sample into with a needle.  When cultured, you can look at it and see if the colonies have spread from the injection site.  If they have, it is probably motile (ie, E-Coli will have colonized all over the tube), others will stay right where you put the needle.  This method at the same time is not fool-proof, cause sometimes, motile bacteria are also aerobic (need oxygen) so will die in the medium.

Answer 2

1. TTC (Triphenyl tetrazolium chloride) is used in motility media to demonstrate motility. When this substance is oxidized it changes color.

2. Bacterial flagella is made of a protein called flaggelin that is added to the tip not the base. eukaryotic flagella is made of microfilaments (microtubules) in a 9+2 configuration. also prokaryotic flagella have a rotational movement. eukaryotic have a whip like motion.

3. periplasmic flagella rotate with the periplasm and aids the bacteria (usually spirochetes) to swim in viscous fluids. In gliding motility the bacteria secretes a slimy material that helps the bacteria adhere to a surface (usuallly with low water content like the soil) and help the bacteria move. the complete mechanism is not known yet.