THE MICROSCOPE, CELLS, AND ORGANELLES LAB

Part 1. The Microscope

 “Part 1”

Table 1. Microscope magnification.

Lens mag.                                                     Ocular mag. (fill in)            Total mag. (fill in)

a.       Scanning              4x               multiplied by                  10x                         =             40x

b.      Low power         10x             multiplied by                  10x                         =             100x

c.       High power         40x             multiplied by                  10x                         =             400x

d.      Oil immersion    100x           multiplied by                  10x                         =             1000x

Part 2. The Virtual Microscope

1.       Two screen shots or photos, as indicated in #4 (1 points)

2.       Names of three structures on each image you viewed through Virtual Microscope

·         The structures I viewed for the onion were the cell wall, nucleus, and the nucleolus. The structures I viewed for the cheek cell were: nucleus, plasma membrane and cytoplasm.

1.       How might the thin, flat shape of cheek cells relate to their function?

·         The flat shape of the check cells act as a sort of protection, they help maintain a stable temperature in the mouth.

2.       What structure separates the contents of the nucleus from the cytoplasm?

·         The nuclear membrane separated the nucleus and the cytoplasm.

3.       What is the function of the nucleoli? Why is this important?

·         The nucleoli contain RNA it is important because it is where the components ribosome’s (RNA and Proteins) are synthesized.

4.       Other than the nucleoplasm and the nucleoli, what are three other materials found in nucleus?

·         The other three materials found in the nucleus are DNA, nuclear membrane and chromatin.

Answer these questions with information you learned from reading this lab, performing the tutorial, and doing the virtual microscope viewing on the University of Delaware site. Complete and proper sentences, please.

5.       When you begin, in what position should the condenser be?  The condenser should be closest to the stage.

6.       Which objective should be in place when you start? When you start the objective should be set at 4X magnification.

7.       Which focusing knob do you first use when you begin looking at a slide? When you begin looking at a slide you start with the coarse focus knob.

8.       What do you adjust if you can see two overlapping circles with part of the object in each circle? To create a single circle to see an object you will need to adjust the eye piece or oculars.

9.       How do you move the slide on the stage? To move a slide on the stage you will use the mechanical stage control.

10.   What device can be opened to increase light? To increase light you can adjust the iris diaphragm.

11.   What is the name of the highest magnifying objective? The highest magnifying objective is oil immersion.

12.   What materials are used to clean slides?  The materials to clean slides are soap and water.

13.   What materials are used to clean objectives? To clean objectives you will use lens paper and cleaner.

14.   Explain the procedure for stowing the microscope.

The steps to stowing your microscope are:

1. Make sure the lowest power objective is in place.

2. Move the stage to the lowest level.

3. Turn off the light source and adjust to the lowest setting.

4. Remove the slide from the stage and clean with soap and water, dry and place back in box.

5. Clean the stage and lenses with lens paper and cleaner. Clean extra careful after oil immersion.

6. Center the mechanical stage, no parts should stick out.

7. Wrap the cord around the head and arm. Place the scope back on the shelf with the corresponding numbers.

15.   Describe two ways you can decrease light intensity. You can decrease light intensity by adjusting the iris diaphragm and the condenser lamp setting.

16.   Which objective allows you to see the largest area of the object that you are viewing? The objective that allows you to see the largest are of an object is oil immersion, it allows you to magnify by 100X.

Part 3. Functions of Cells and Organelles

Procedure:

1.       Take a photo of the two labeled containers with their contents.

1.       Record your predictions and rationale. My prediction is that the carrot in the freshwater will not change as there is no other element in the water to change the cellular structure. The carrot in the saltwater I believe will become bloated and increase a little in size as our bodies do that when we have too much salt.

2.       Take a photo of the carrots next to each other outside of the containers.

3.       Record more observations.  

·         Note if there are any differences in the tightness of the strings and the textures for both carrots. Observe which type of water caused an increase in cell size.  

       

    The strings did not seem any tighter, they were just soaked with water. The texture of the carrot in freshwater did not look or feel much different than when I put it in the water. It did seem to turn a brighter orange. The carrot in the saltwater seemed slimy when I first took it out of the water it was very easy to bend it. I noticed also when I squeezed the carrot in the saltwater you could see water coming out but not with the freshwater carrot. Through the night I also noticed that the saltwater carrot seemed to float but the one in freshwater did not.

               

·         Discuss the actual results in the measurements compared to your predictions. Include:

                The saltwater caused a decrease in cell size and caused the carrot to shrink, I thought that it would become bigger as salt bloats a person. The cells lost water and started to shrink and the water loss was noticeable when I squeezed the carrot and could see water coming out of the carrot. The cellular structure was changing in the whole carrot and if the carrot had been in the water much longer the cells would have shriveled up.

Remember science does not prove anything to be true. Through experimentation, results can illustrate processes and these processes may be used to predict similar events in similar or different circumstances.

4.       What is osmosis? Osmosis is the net diffusion of water across a selectively permeable membrane. It is the passage of a higher and lower concentration of a solution into a semi permeable membrane that separates the two solutions, when the solution becomes equal in concentration it stops the flow. Osmosis is important because it is how nutrients are delivered to cells.

Table 2. Starting and Ending Carrot Measurements

	Length at Start of 24 Hours	Length at End of 24 Hours	Width at Start of 24 Hours	Width at End of 24 Hours
Freshwater Carrot	4 in	4in	1in	1in
Saltwater Carrot	4in	3  3/4in	15/16 in	3/4in