A scientist isolates a microbe from a contaminated water source. She thinks that the organism might be a new bacteria that is ca
pable of surviving in the presence of lead, a heavy metal. She makes tubes of growth medium containing either no lead, 0.1 mg lead, 0.25 mg lead, 0.5 mg of lead or 1 mg of lead. She inoculates each tube with the 10 x 10e3 cells of the new organism and then incubates the inoculated medium at 37-degree Celsius. After 48 hours, she examines the tubes of medium and finds that there is no growth in any of them. However, she finds that the bacteria grew fine in a medium that did not contain any lead. She decides to repeat the experiment using lower concentrations of lead than those she used initially. what conclusion can the scientist in this scenario make from her result 1) all contaminated water contains high levels of lead and other heavy metals
2) the amount of lead used in the experiment killed the bacteria being tested
3) all experiment should be repeated three times or more
4) lead-contaminated water does not contain any bacteria at all
5) the test bacteria take more than 48 hours to grow in the laboratory when incubated at 37 degree Celsius
2) the amount of lead used in the experiment killed the bacteria being tested
Explanation:
The bacterial colonies that women cultivate do not develop in media with these dimensions of lead.
It does not influence the number of hours or the temperature because if a group could proliferate and had the time necessary to develop the rest, it should also do so.
That is why the study should be repeated with lower lead identifications and be able to verify specifically if the hypothesis raised is correct: This group of bacteria does not grow in leaded media, either because lead has a bactericidal or bacteriostatic effect on these colonies.
