what are ocular lenses? how much do they magnify?
magnify specimens 10x; lenses you look through
what is the revolving nose piece?
disc above objective lenses that allows the user to change lenses
what are the objective lenses?
lenses that magnify specimens 4x, 10x, or 40x
what is the slide carrier, where is it located, how is it moved?
- located on stage
- for holding slides in place
- movable using knobs at the side of the stage
what is the condenser, how do you move it?
- focuses light into a narrow beam that is directed onto the specimen
- raise/lower condenser with Condenser adjustment knob
what does the iris diaphragm control, where is located, how is it moved?
- controls contrast
- located under condenser
- movable by handle/dial
what are the coarse and fine focus knobs?
- Coarse focus knob → larger of two knobs; visibly moves stage up and down. Used on 4x and 10x, but never 40x
- Fine focus knob → smaller of the two knobs; also moves stage, but almost imperceptibly
what is the illuminator, how is it controlled?
-where light exits the bottom of the microscope; controlled by transformer control knob
what is a microscope used for?
The microscope is a tool used to view the structure and subcellular structure of cells, singly or in tissues
how is total microscope magnification calculated? what is the total microscope magnification at low, medium, and high magnification?
- calculated by multiplying the magnifying power of the objective lens and the ocular lens
- The ocular lens (eyepiece) magnification is 10x
- The objective lens are 4x, 10x, and 40x
- Total magnification of low lens power → 10x X 4x = 40x
- Total magnification of medium lens power → 10x X 10x = 100x
- Total magnification of high lens power → 10x X 40x = 400x
what is field of view? what happens to field of view when switching from low power to high power?
- the circular area of the slide that is visible through the eyepieces
- gets smaller when you switch from a lower power to a higher power
how do you calculate the actual size of something in the field of view?
field of view (mm)
/
amount of times a specimen would fit length wise in the field of view
eg. high power (40x) –> field of view is 0.40 mm, item could fit 15 times
0.40/15 = 0.027mm
how do you show actual size on a drawing?
- add the calculation for actual size (estimated)
- as well as a scale bar beside the length of cell which is labelled
- add total magnification = (40x, 100x, 400x)
what 4 things does a figure caption need to include?
- Type of figure → drawing, graph, diagram etc
- What the figure is → cell, cross section, tissue, or organism
- Scientific name
- Features of significance with reference to labels
- Eg. Figure 1. Drawing of a cell from Vallisneria sp. (eelgrass) showing cellular detail.
what are the 3 steps in making a wet mount?
- Place a single drop of water in the centre of microscope slide
- Add specimen
- Add coverslip by placing one edge of the coverslip at the edge of the water drop and gently lowering
what are some key characteristics of plant cells?
- Rectangular/squareish
- Cell wall
- Chloroplasts
- Larger than animal cells
- often green
what are some key characteristics of animal cells?
- Roundish
- No cell wall
- No chloroplasts
- Smaller than animals
- can sometimes see nucleus
