Difference between revisions of "Kmeilak Week 7"

Revision as of 06:30, 9 October 2013

Discovery Questions from Chapter 4

5. Choose two genes from Figure 4.6 (PDF of figures on MyLMUConnect) and draw a graph to represent the change in transcription over time.

Media:Microarray_Graph.pdf

6b. Look at Figure 4.7, which depicts the loss of oxygen over time and the transcriptional response of three genes. These data are the ratios of transcription for genes X, Y, and Z during the depletion of oxygen. Using the color scale from Figure 4.6 (bright, medium, dim green, black, dim, medium, or bright red), determine the color for each ratio in Figure 4.7b.

• Gene X (1 hour): black
• Gene X (3 hours): dim red
• Gene X (5 hours): black
• Gene X (9 hours): medium green
• Gene Y (1 hour): black
• Gene Y (3 hours): medium red
• Gene Y (5 hours): dim green
• Gene Y (9 hours): bright green
• Gene Z (1 hour): black
• Gene Z (3 hours): dim red
• Gene Z (5 hours): dim red
• Gene Z (9 hours): dim red

7. Were any of the genes in Figure 4.7b transcribed similarly?

Yes, Gene X and Gene Y begin at 1.0, were induced at the 3 hour mark, and then were repressed at the 5 hour mark and was further repressed at the 9 hour mark.

9. Why would most spots be yellow at the first time point?

Most spots would be yellow at the first time point because of a delayed transcriptional reaction to changed environmental conditions. Initially, the gene expression would be the same as the control because not enough time had passed for significant gene expression changes.

10. Go to [1] and search for the gene TEF4; you will see it is involved in translation. Look at the time point labeled OD 3.7 in Figure 4.12, and find the TEF4 spot. Over the course of this experiment, was TEF4 induced or repressed? Hypothesize why TEF4’s gene regulation was part of the cell’s response to a reduction in available glucose (i.e., the only available food).

TEF4 was repressed over the course of this experiment. It is most likely that this repression occurred with a reduction in available glucose because TEF4 helps bind AA-tRNA to ribosomes. With less glucose, and therefore less energy available, the cell would most likely become more conservative in gene expression and express fewer genes, lessening the need to expend energy transcribing a gene whose product aids in the binding of tRNA because there is less translation in the cell with reduced energy available.

11. Why would TCA cycle genes be induced if the glucose supply is running out?

• Main Page
• Kevin's User Page
• Week 1
• Week 2
• Week 3
• Week 4
• Week 5
• Week 6
• Week 7
• Week 8
• Week 9
• Week 10
• Week 11
• Week 12
• Week 13
• Week 14
• Week 15
• Class Journal Week 1
• Class Journal Week 2
• Class Journal Week 3
• Class Journal Week 4
• Class Journal Week 5
• Class Journal Week 6
• Class Journal Week 7
• Class Journal Week 8
• Class Journal Week 9
• Class Journal Week 10
• Class Journal Week 11
• Class Journal Week 12
• Class Journal Week 13
• Class Journal Week 14
• Class Journal Week 15
• Kmeilak Week 2
• Kmeilak Week 3
• Kmeilak Week 4
• Kmeilak Week 5
• Kmeilak Week 6
• Kmeilak Week 7
• Kmeilak Week 8
• Kmeilak Week 9
• Kmeilak Week 10
• Kmeilak Week 11
• Kmeilak Week 12
• Kmeilak Week 13
• Kmeilak Week 14
• Kmeilak Week 15

Kmeilak (talk) 21:20, 12 September 2013 (PDT)