Question

How many colonies would be present on a plate after plating .5 mls of 10^-6 dilution liquid sample that contains 1x10^8 organism/ml?

At 3:00pm, you inocculate 1x10^3 cells in a flask on nutrient broth. The cells have a lag phase that last an hour. At 8:00pm, the cultureenters stationary phase. At that time, there are 6.5x10^7 cells in the flask. Calculate the number of generations, the number of generations/hour and the doubling time or number of hours/generation.

Answer 1

oK FROM QUESTION I DO UNDERSTAND THAT 10^{^-6} diluted sample contain 1x10^8 organism/ml if am i right diluted sample itself contian 1x10^8 organism/ml

so very simple 1 ml contain 1x10^8 organism so 0.5 ml would contain half of that 0.5X10^8 organism/ml means 5x10^7 organism/ml

if i assume ( not clear in question) the sample contain 1x10^8 organism/ml which is now diluted 10^-6, then in this condition number of organims would be 1x10^8 organism/ml devided by 10^6 that is 1X10²

and then in this condition in 0.5 ml number of organism would be 0.5 X10^{2 or} 5X10³

part 2 now

strating cells 1x10^3 ends number of cells 6.5x10^7 in 4 hours (from 4 pm to 8 pm)

Exponential Growth Rate 14.967184

Doubling Time: 3.997038 ( around 4 minuts), so number of genertaion would be 60/4 , 15 generation/ hour so total 60 generation

Bacteria Growth Rate Formula:

   N_t = N₀ * ( 1 + r)^t
where:
   N_t: The amount at time t
   N₀: The amount at time 0
   r: Growth rate
   t: Time passed