Biology Forums - Study Force

Hello, I'm stuck on a question, specifically ii. Could anyone help me out? Also, for i I've put the empty vector is the control, is this correct?

In the first set of experiments, COS-7 cells were manipulated (transfected) to Introduce a
plasmid vector containing the coding sequence for myosin 'IA or myosin 118 so that they could
overexpress the isoform in question (i.e. to increase the level of expression beyond the level
of endogenous expression of the gene). Note that COS-7 cells transfected with myosin 'IA or
myosin 118 not only express the transfected isoform but also express their endogenous
myosin Il isoforms and therefore contain more myosin Il than non-transfected cells. The
researchers seeded a known number of COS-7 cells in a cell culture dish and transfected
cultures to overexpress either myosin IA or myosin 118, as described above. After three days,
they stained the nuclei of the cells with a DNA-binding dye and captured images of the
cultures using a fluorescence microscope (Figure 1 By counting the nuclei within a fixed
field-of-view it is possible to determine the number of cells that have adhered to the culture
dish in the different cultures, as only the nuclei of adherent cells will be visible.

a. The following part-questions require you to analyse and interpret the data presented in
Figure 1.
i. In Figure 1, which of the treatments is the control for this particular experiment?
Explain your answer. (2 marks)

ii. For each of the three different cultures in Figure 1 , count and record how many
cells have adhered to the culture dishes per field and then, for each of the
experimental treatments, express the number of adherent cells as a % of those in
the control. (3 marks)

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Ah ok I was interpreting the question wrong, I was dividing the cells in the empty vector by the other 2 and kept getting odd percentages. Thank you for the help, all the other questions relate to drawing a graph based on the percentages which I now can do.

I counted 85 for my IIB, divided by 12 = 7.08 x 100 to get a percentage but it gives me 708%?

The math is right, no doubt about that.

If what I said is correct, then report that number. I'm not 100% sure that's what you do, but it makes sense. The ratio is definitely around 7 to 1. You could also say that the control colony consists of 12/85 * 100%, but I like the former way.

I see, I have to plot a graph, so would it be stupid to say a 708% increase from the empty vector? I'm having a hard time interpreting the question.

Yes, 708% increase is right. That's precisely what we're witnessing

brilliant, thanks!