Biology 347 - General Physiology Lab - Stark and Kumar - Fall 2004

Quiz 1 - Postquiz on Computer and Prequiz on Electrophysiology, 9/9/04

1. What is the purpose of adding the equation and R-squared value on the graph from Excel?

The equation will give the slope; slopes are useful because they show rate of change. The R-squared value indicates correlation, and tells how well the given equation represents the data.

2. You are having a discussion as to whose papers, Prof. Mayden's or Prof. Stark's, are in the references of more papers. Where would you go to answer this question?

What was, at one time, called the Science Citation Index is now the ISI Web of Science available on line at this site.

3. High- and low-pass filters involve an RC circuit. What does the C stand for?

capacirance, the answer being given away for free down on #9.

4. Pretend the polygraph is a graph in an algebra class. What is on the X axis?

time, this question almost identical to one from last year on the electrophysiology link

5. The channel amplifier has settings of 2, 5, 10 (etc.) mV/cm. The signal you are recording seems to be just a little too big to fit on-scale at the setting of 5. What should you do?

Switch it to 10, not 2

6. Suppose you wanted to take a recording made on the Mac-based Powerlab and post it on the web so that anybody could see it, even if they did not have T-chart or if they have a PC, what do you do?

Select, zoom, copy, paste into PhotoShop, Flatten, save as jpg

7.When should the median be used instead of the mean?

When there is a significant outlier that results in the mean inaccurately representing the data.

8. A typical glass micropipette might have a resistance of 10. Ten what?

meg Ohms

9. This high value, combined with the high capacitance from glass, might make the glass micropipette slow for recording fast potentials. Why?

a low-pass RC filter, see second question on last year's quiz

10. The web site has a photograph of a voltmeter (like Fig. 5-37, Silverthorn). Why can't you use such a device to measure a neural signal? (i.e. Why do you need a chart recorder, a polygraph, an oscilloscope, or a computer instead?)

You need to record fast signals, in other words, voltage as a function of time (3rd question last year)

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