I m in AP Biology and i don't know what the heck a negative control is...the experiment was way too confusing and i m having problems answering the questions. Please...someone help!!!
2006-10-14 14:51:11 · 5 answers · asked by jessi 1 in Science & Mathematics ➔ Biology
In the simplest terms, a negative control experiment is one in which the experimental variable is not applied, in order to determine the vailidty of the tested variable. For instance, you are testing the effects of added glucose to the growth of a culture of bacteria. To make certain that the effect that you observe is not related to simply say the dilution caused by addition of the glucose solution you would add to a parallel culture the exact same volume of say water or a buffer that has no impact on bacterial growth. By doing this you can eliminate the effects of simply diluting the culture and address how much the glucose solution effects the growth.
2006-10-15 01:28:20 · answer #1 · answered by Gene Guy 5 · 0⤊ 0⤋
A negative control is a parallel experiment run in exactly the same way as the test experiment, except for the single factor being tested. For example, if you want to know whether a new drug will kill a specific organism, you run two sets of bacterial culture plates, one without the drug and one with it. Both sets are cultured for exactly the same time, in the same incubator, under precisely the same conditions. Then, if you see an effect in the drugged cultures that you don't see in the negative controls, you know the effect is due to the drug. If you ran the experiment without the control cultures, someone could say "perhaps the effect was due to a malfunction in the incubator" or "perhaps the bacteria the cultures were innoculated with were non-viable", or perhaps ... whatever. But the fact that "nothing" happened in the control proves that whatever happened in the test cultures was in fact due to the factor being tested.
2006-10-15 04:00:51 · answer #2 · answered by PaulCyp 7 · 1⤊ 0⤋
A negative control is known to give a negative result.
In other words, and in the most simple of terms, a negative control experiment is one in which the desired outcome is no effect.
2006-10-14 22:05:13 · answer #3 · answered by Michael 4 · 0⤊ 1⤋
A parallel experiment preformed under the same conditions, except the variable is different in the negative control experiment.
2006-10-14 22:00:11 · answer #4 · answered by Anonymous · 0⤊ 1⤋
In experimental design they don't use the term negative control, but I ran across the following web site for RNA's but I have not studied it.
http://www.ambion.com/catalog/CatNum.php?4611
2006-10-14 22:05:25 · answer #5 · answered by Anonymous · 0⤊ 1⤋