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keepgoing
.....  Topics: 109 Posts: 1865 |
A bacterium, has lag phase of 40 min and generation time of 20min...how many cells will be there at the end of 120min,if there are 4000 cells to begin with and there is no stationary phase? 1.4 X 10(power 12) 2. 2.56 X 10(5) 3. 6.4 X 10(4) 4. 3.2 X 10(4) 5. 1.6 X 10(4)
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NNL
| Awaitin The Unexpected  Topics: 779 Posts: 6613
No Way I know this u will have to Explain me this.
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rock
| Forum Elite  Topics: 23 Posts: 303
5-16000
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indidoc1
| IMG physician  Topics: 104 Posts: 2083
3- 6.4* 10000  Edited by indidoc1 on Apr 01, 2007 - 6:15 AM
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asherif
| Forum Newbie Topics: 0 Posts: 46
answer ==> 3. 6.4 X 10(4) initial number of bacteria (4000) we have 120 min generation time (time which bacteria need to double) after 40 mins (lag phase) bacteria will start multiplying (we still have 4000) after 20 mins(60 mins from the begining) bacteria will be 8000 after 20 mins(80 mins) 16000 after 20 mins (100 mins) 32000 after 20 mins (120 mins) 64000 64000 = 6.4X10(4) feel free to correct me if I'm wrong  Edited by asherif on Apr 01, 2007 - 7:33 AM
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keepgoing
| ..... Topics: 109 Posts: 1865
very well indi  after 120 mintues,there would be 6.4 X 10(4)bacteria.As bacteria divides by BINARY FISSION there division would be like(considering no stationary phase) TIME------------>Bacterial conc. 0---------------->4 X 10(3) ((((bcos we assumed 4000 cells to being with) 40(lag phase)--->4 X10(3) 60---------------->8 x 10(3) 80---------------->16 X 10(30 or 1.6 X 10(4)****ROCK it can not be b/c its juz 80 min and our target time is 120 min... 100--------------->32 X 10(3) or 3.2 X 10(4) 120--------------->64 X 10(3) or 6.4 X 10(4)
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keepgoing
| ..... Topics: 109 Posts: 1865
 ashrif good job!
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rock
| Forum Elite Topics: 23 Posts: 303
good question...learnt something today(everyday yu learn something new)....i actually thought that the bacteria after their first division will again go into the lag phase before starting to divide again and so i came to 16000 as the answer. well now i know the right thingthanks keepgoing, i appreciate it...
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keepgoing
| ..... Topics: 109 Posts: 1865
rock
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lq2006
| Forum Elite Topics: 42 Posts: 379
3. 6.4 X 10(4)
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dncosta
| Licensed, finally  Topics: 19 Posts: 601
6.4X10(4)
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unique1
| __________  Topics: 16 Posts: 1964
Good question and explanation . Thanks keepgoing. Calculations are my nightmare 
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SmokyWaters
| Forum Elite Topics: 6 Posts: 432
6.4
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SmokyWaters
| Forum Elite Topics: 6 Posts: 432
6.4 ...easy way to calculate... 120-40 = 80 divide it by 20 which is the doubling time...gives 4 as answer 2 raised to the power 4 (doubling times) givs u 2 x 2 x 2 x 2 = 16 as the number of times it has multiplied...simple multiply 16 with the initial number easy way for many (who re bad at maths) is to REMEMBER this if 2 doubling times then just multiply the initial number by 4 3 doubling times then just multiply the initial number by 8 4 doubling times then just multiply the initial number by 16 5 doubling times then just multiply the initial number by 32 they arent goin to ask further ..m sure
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