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 103 cells of the new organism and then incubates the inoculated medium at 37oC. 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 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
The positive control is the treatment where bacteria grew without lead. Since positive control indicates the presence of bacteria in the experimental conditions, it is possible to confirm that they only death in presence of this metal. However, it is important to note that it is imperative to repeat this experiment three times and also to include a negative control in order to confirm these results.
It might have animals that depend on this "animal" for a food source. If we were to remove it, all the animals that are after this "animal" on the food chain will die out and the animals that they eat will over populate.
Answer: Low levels of testosterone has been linked to joint pain and may cause rheumatoid arthritis in the long run. Rapid growth can lead to joint damage as <span>the accelerated bone growth disrupts the supply of blood to the cartilage, causing bone death and regrowth.
In this case, the chromosome haploid number (n) of the target species is equal to 10, and therefore its diploid number (2n) is equal to 5 (i.e., somatic cells in the target species contain 5 pairs of chromosomes). That means that one individual can produce 2⁵ or 32 different gametic combinations. Moreover, the number of possible combinations that emerge from paring different gametes (sexual reproduction) can be calculated as (32)² = 1024 combinations.
