A scientist isolates a microbe from a contaminated water source. She thinks that
ID: 141850 • Letter: A
Question
A scientist isolates a microbe from a contaminated water source. She thinks that the organism might be a new bacteria that is capable 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
Explanation / Answer
Bacteria show lower growth because lead is the inhibitor because here lead is reacting with metabolites of bacteria and consequently produced inhibitory products. Okay
Now come to the point :--
1. Contaminated water having pollutant like lead(Pb) as well as other heavy metals. So growth will get decreased.
2. No, It will not kill but stop the growth with inhibitor effect.
3. As the repeats are increasing means lead is continuously increasing so growth will keep decreasing.
4. No. Thats not true because it just stops the growth and does not allow to multiply.
That's it
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