Question

1. (32 pts, total) Use the following information for the next 6 questions. The "rushing fireball" is a motile prokaryote. It was originally isolated from a marine (ocean) environment. It does not fix carbon dioxide. It uses sugars and proteins as sources of energy, and it can oxidize elemental sulfur (S) or organic compounds for metabolism. It has a single cellular membrane surrounded by protein only. A graph comparing generations/doublings per day (vertical axis) with temperature (horizontal axis in degrees Celsius) is shown in Fig. 1. An image of Microbe T obtained under vacuum is shown in Fig. 2. The white bar in the lower right corner of the images presented in Fig. 2. A and B indicate 5 um and 2 um, respectively. J. Bacteriol. 2006 October, 188(19): 6915-6923. doi: 10.1128/JB.00527-06). Fig. 2 Fig. 1 Generations per day 241 104 100 96 92 88 Temperature, C 1. (4 pts.) Suppose you are growing the rushing fireball in liquid culture at optimal growth temperature. E E

Answer 1

Page 1 U according to the graph, if the culture growon at optimal temperature the number of cells doubles a4 times a day. If you divide the total dublings with the tolal hour will get the time needed for a single doubling [doubling time] so, Doubling time = 24hours /24 doublings = thr. for every one hour there will be an Exponential increase in cell number The current co S 0.8 How many hours would have taken to reach oog op from 0,2. OD ? of would taken a doublings (0.2 ---->0.4 --->08) reach one from 0-2 OD. Each dolebling takes thr,so the op of the culture was 0.2, 2 hours Eanieri 2) with reference to the graph of the culture grown at 88°C the dublogs per day fs

page-2 So, in 24 hours ( 8 am to gam) the culture would have undergone 4 doublings. so the final OD after 4 doublings will be 16 (0.1 --->0.2----> 0,4 ----> 0...-46)