Lab 3 Mircsope Cells and Organelles

Part I

Table 1. Microscope magnification.

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

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

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

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

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

Part II

 
          

Onion Root

1.      Cell membrane

2.      Cytoplasm

3.      Nucleus

Cheek Cells

Plasma membrane

Nucleus

Cytoplasm

How might the thin, flat shape of cheek cells relate to their function?  They are like tiles or roofing shingles.  This is perfect shape for protecting & covering over the inside of the cheek.

What structure separates the contents of the nucleus from the cytoplasm?  The Nuclear Membrane separates the contents of the nucleus from the cytoplasm.

What is the function of the nucleoli? Why is this important?  The nucleoli make ribosomal subunits from proteins & ribosomal RNA.  The importance of the ribosomal is that it makes proteins for the cell.

Other than the nucleoplasm and the nucleoli, what are three other materials found in a nucleus? A) DNA, B) Chromatin, C) Nuclear Pore

When you begin, in what position should the condenser be? The condenser should be at its highest level when you first start to use the microscope.

Which objective should be in place when you start?  Objective 4X should be your starting point when looking through the oculars.

Which focusing knob do you first use when you begin looking at a slide?  The Coarse Adjusting knob will be used to help you focus.

What do you adjust if you can see two overlapping circles with part of the object in each circle?  While looking through eyepiece (Oculars) you adjust them in or out till you only see one circle.

How do you move the slide on the stage? To move the slide on the stage you would use the coarse adjustment knob.

What device can be opened to increase light?  A person would use the Diaphragm or Light intensity knob to increase the light.

What is the name of the highest magnifying objective?  The highest magnifying objective is 10X or High Dry

What materials are used to clean slides?  To clean slides it is recommended to use only soap and water.

What materials are used to clean objectives?  Lens paper or Lens cleaner should be used when cleaning the objective lens.

Explain the procedure for stowing the microscope.  Make sure the lowest power objective lens is in place, turn lamp to lowest setting, remove any slides from the stage and wrap cord around arm or head.  Place on the shelf.

Describe two ways you can decrease light intensity.  Adjusting the condenser down or adding a blue filter.

Which objective allows you to see the largest area of the object that you are viewing? 4X would be the best objective to use in this circumstances.

Part III

 Record your predictions and rationale.  The Carrot immersed in salt water will shrink and be limp due to dehydration (the saltwater solution drawing the water out of the carrot) causing the string to fall off and the carrot in freshwater will expand due to adding hydration causing the string to tighten and possibly extend.  

 Note if there are any differences in the tightness of the strings and the textures for both carrots.  The carrot in the freshwater expanded causing the string to tightened. Where as the saltwater carrot became limp and the string fell off.

 Observe which type of water caused an increase in cell size. The Freshwater caused a increase in cell size. and the Saltwater caused a decreased in cell size.

What is osmosis? Osmosis is the net diffusion of water across a selectively permeable membrane such as cell membrane.

What is moving? Water  Why? Because the water is trying to find a equal Librium in concentration.

How is this important for the health of cells?   Health Cells depend on water to keep an even balance of Osmotic pressure.  If a person were to drink a larger amount of saltwater there body would start to dehydrate.

 

 

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 ¼”	4 ½	5/8”	¾”
Saltwater Carrot	4 ¼”	3 ¾”	5/8”	½”