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Bio1AL_Fa09_lab2_prelab

# Bio1AL_Fa09_lab2_prelab -...

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Unformatted text preview: Micropipetter, Microscope and Cells Pre‐lab.  Due at the start of lab.    (Pages 11­44 in the lab manual)    Name             GSI & Sect #            Station #      1)  What should you do if the fire alarm sounds while you are in a biology lab?        2)  What is the predicted weight of 100 microliters of de‐ionized water?       (include units)     3)  A student weighs 10 different samples with their P‐200 micropippetter set to 100 microliters.  The values are:  0.105 g, 0.104 g, 0.104 g, 0.102 g, 0.101 g,  0.101 g , 0.100 g, 0.099 g, 0.099 g, and 0.098 g.     mean = ______________ g (Note the use of units!)      4)  Calculate the number of water molecules represented by the mean value in number 3.  Show your work.      # of water molecules = ______________      5)  Diagram the window for withdrawing 15 µl of a solution with the P20 micropipettor.        6)  Where do you dispose of used pipette tips?        7)  Why do you want to set critical illumination for each specimen examined?        8)  To the right make a small sketch of a  compound microscope like the one shown on  page 20 (Fig. 4).  Label: on/off switch,  objective   lenses, stage, focus knobs and the condenser.        9)  Outline the correct use of the microscope, from specimen until critical illumination has been achieved in detail  (especially the steps that involve the field and aperture diaphragms).  The first few steps are provided (Hint: this  question could be a quiz question!).  Don’t just copy the lab manual but instead think about the steps!!    For example the reason you do not use the coarse focus knob with medium to high power objectives is because of  the limited working distance (the distance between the objective lens and the slide).  a)  Turn the switch off, set the lamp intensity to the lowest setting (1), and plug in the microscope.  b)  Using the condenser adjustment knobs, raise the condenser to its uppermost position.  c)  Use the coarse focus knob to lower the stage to its lowest point.  d)  Using lens paper, clean the objective and ocular lenses.            Continued on the Backside  A11 – Fall 2009  10)  What solution do you add to your slides to slow down protists?      11)  How do you make a wet mount of Volvox?  You want to avoid bubbles.      12)  In the space to the right, make a drawing of  any common object that is greater than 15 cm in  size.  Include a title, appropriate labels, details  and a scale bar (use convenient, round  numbers). Drawing guidelines are on page 19.   Note that you cannot draw this large object to  actual dimensions and must shrink the object.   Thus the scale bar is required.  This is true for  your microscope drawings, but in reverse, you  will make drawings much large than actual size.     13)  Answer the following questions for each figure.  The lines are 100 micrometers apart.  The measuring device  is called a micrometer but a "ruler" may be a more useful term.  This avoids the distinction between distances  measured in micrometers, versus the measuring device known as a micrometer.  For each figure (include units):    a)  How wide is the field of view?    b)  How many divisions, on the “ruler”, fit into 100 micrometers?    c)  What is the distance that each “ruler” division represents?    14)  The image of Trichonympha (from figure 20a on page 40) is shown below but this represents only one  viewing angle.  When you examine your slide it could potentially be in any angle (and moving).  Try to predict  what it would look like from a different viewpoint.  In this case, imagine you are at the lower right edge looking  directly onto the organism (about a 45°angle, as shown by the arrow).  Make a drawing of how you think it would  look from this perspective.  The purpose of this exercise is to have you realize that specimens can be in any  particular orientation, not just the one that is drawn in the lab manual.  Check out your prediction in lab!                  Your Drawing:  A12 – Fall 2009  ...
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