Question
Their research with plant mechanical wounding led the UNL scientists to create the line graph in Figure 6. However, the draft of the graph is not fully labeled. The graph does not show which line went with which type of Arabidopsis plant as well as the time points along the x-axis. Based on the data depicted in the graph above:
Looks Good! Good job! Scott reported in the video that JA-Ile peaks from mechanical wounding in the wild-type plants were ~10-fold greater than that of the jar1 mutants, so line A must be the wild-type data. Time c must be 60 min or less because Scott said it was determined that the JA-Ile peaks occur within the first hour after mechanical wounding.
Question
The UNL scientists hypothesized that insects feeding on the Arabidopsis plants might also cause the same response via JAR1 activity that occurs when the plants are mechanically wounded. How could this be tested?
Looks Good! Good job! To ensure consistency, insects would have to feed for a fixed amount of time on all plants, and then the tissue would have to be sampled at select time intervals, not solely at the end. Having insects feed on both wild-type plants and jar1 mutants would give both a positive control and a treatment, a means by which to make comparisons over time between the two Arabidopsis genotypes (wild-type and jar1) that were subjected to the same treatment. Sampling the plant tissue at the end instead of at select time intervals would not provide any information on the trend of JAR1 activity over time, so it would be impossible to make a good comparison.
Question
If JAR1 activity enables the Arabidopsis plants to mount a defense, insect feeding might somehow differ when feeding on the wild-type plants compared with the jar1 mutants. How could this hypothesis be tested?
Looks Good! Good job! Having insects feed on both wild-type plants and jar1 mutants would give a both a positive control and a treatment a means of which to make comparisons to verify treatment effects. This could only be accomplished by allowing insects to feed exclusively on one type of plant and exclusively on the other.
Question
When the UNL scientists were establishing their testing environment, their second requirement was “Arabidopsis plants that were considered genetically normal.” Why would they need this?
Looks Good! Good job! A positive “control” was needed to establish a baseline from which to compare data. Their data would really not make much sense in the long run without having plants that were considered genetically normal (wild-type) to compare to the jar1 mutants. Also, their research would likely not get published for the same reasons; there was no baseline from which to compare data.
Question
When the UNL scientists were establishing their testing environment, their third requirement was “Arabidopsis plants that were homozygous for the jar1 mutation.” Why would this be important?
Sorry. Your answer is incorrect. The jar1 mutation had to be homozygous because it would guarantee that all insects feeding on the jar1 mutants would be affected equally the same because all, not half, jar1 plants would be expressing the jar1 mutation (causing reduced JAR1 activity), thus maintaining consistency. In addition, since the plants would be homozygous for the mutation, Scott could self the plants, collect the seed, and plant them for more of the same experiments knowing all plants, not just half, of the selfed-generation would have to be homozygous for the jar1 mutation, too, based on simple Mendelian genetics.
Sorry. Your answer is incorrect. The jar1 mutation had to be homozygous because it would guarantee that all insects feeding on the jar1 mutants would be affected equally the same because all, not half, jar1 plants would be expressing the jar1 mutation (causing reduced JAR1 activity), thus maintaining consistency. In addition, since the plants would be homozygous for the mutation, Scott could self the plants, collect the seed, and plant them for more of the same experiments knowing all plants, not just half, of the selfed-generation would have to be homozygous for the jar1 mutation, too, based on simple Mendelian genetics.
Good job! The jar1 mutation had to be homozygous because it would guarantee that all insects feeding on the jar1 mutants would be affected equally the same because all jar1 plants would be expressing the jar1 mutation (causing reduced JAR1 activity), thus maintaining consistency. In addition, since the plants would be homozygous for the mutation, Scott could self the plants, collect the seed, and plant them for more of the same experiments knowing that all plants of the selfed-generation would have to be homozygous for the jar1 mutation, too, based on simple Mendelian genetics.
Sorry. Your answer is incorrect. The jar1 mutation had to be homozygous because it would guarantee that all insects feeding on the jar1 mutants would be affected equally the same because all, not half, jar1 plants would be expressing the jar1 mutation (causing reduced JAR1 activity), thus maintaining consistency. In addition, since the plants would be homozygous for the mutation, Scott could self the plants, collect the seed, and plant them for more of the same experiments knowing all plants, not just half, of the selfed-generation would have to be homozygous for the jar1 mutation, too, based on simple Mendelian genetics.
Looks Good! Good job! The jar1 mutation had to be homozygous because it would guarantee that all insects feeding on the jar1 mutants would be affected equally the same because all jar1 plants would be expressing the jar1 mutation (causing reduced JAR1 activity), thus maintaining consistency. In addition, since the plants would be homozygous for the mutation, Scott could self the plants, collect the seed, and plant them for more of the same experiments knowing that all plants of the selfed-generation would have to be homozygous for the jar1 mutation, too, based on simple Mendelian genetics.