After performing Gelatin Hydrolysis test on two different or…

After performing Gelatin Hydrolysis test on two different organisms in separate test tubes labeled 1 and 2, you observed the results. a) Which test tube shows positive result 1 or 2?  b) What enzymatic process does gelatin hydrolysis test for? c) Why do we use an ice-bath in this test?   

You perform a serial dilution series of the same species of…

You perform a serial dilution series of the same species of bacteria onto identical agar plates, all incubated for 24 hours at the same temperature. Shown from upper left to lower right are bacterial dilution concentrations of 10-2, 10-4, and 10-6. Given that the agar plates and bacterial sample were identical before diluting, what is the best explanation for the difference seen in bacterial colony size amongst the three plates?