Q1. Suppose after washing your hands, you leave ten bacterial cells on the new bar of soap. You next decide to do a plate count of the soap after it is left in the soap dish for 24 hours. You dilute 1g of the soap 1:10 and plate it on a standard plate count agar. After 24 hours of incubation, there are 168 colonies. How many bacteria were on the soap? How did they get there?

Q2. Some photosynthetic bacteria (for example purple sulfur bacteria) have photosystem I but not II, while others have both PSI anxd PSII. Which is the might this observation implies?