Week 3. The Microscope, Cells, and Organelles Lab.

Part 1 

 The microscope magnification.

                             Lens mag.                                Ocular mag.                    Total mag.
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

Virtual Microscope
                         
    ONION ROOT  

                        

4x

10x

40x

100x

Onion root, under magnification of 100x, has the visible cells with their nucleus (dark blue), cytoplasm (lighter blue substance surrounding the nucleus), and cell walls (which are better viewed at mag. 40x).

CHEEK CELLS SMEAR

4x

10x

40x

100x

In the cheek cell image, with mag. of 100x., I can see the nucleus, cytoplasm, and organelles (in the 40x mag. image.)

Answers to part 2 questions.

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

The double-layered membrane, called the nuclear membrane, separates the nucleus from the cytoplasm. 

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

The nucleoli are located in the body of the nucleus. As the nucleus is the "brain" of the cell, the nucleolus (numerous nucleoli) could loosely be thought of as the brain of the nucleus. The nucleolus takes up around 25% of the volume of the nucleus.This structure is made up of proteins and ribonucleic acids (RNA). Its main function is to rewrite ribosomal RNA (rRNA) and combine it with proteins. This results in the formation of incomplete ribosomes. It produces the energy.

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

The three materials that found in a nucleus, besides nucleoplasm and nucleoli, are DNA, RNA, and ribosomal proteins. 

Operating the Microscope.

4. Which objective should be in place when you start?

The smallest magnification objective should be in place when we start, usually it is the scanning one, with mag. of 4x.

5. Which focusing knob do you first use when you begin looking at a slide?

When we begin looking at a slide, we first use the coarse knob to focus on it. 

6. What do you adjust if you can see two overlapping circles with part of the object in each circle?

To eliminate the two overlapping circles when looking at the slide, we have to adjust the oculars by moving them from side to side, until the desired one circle, with proper focus. 

7. How do you move the slide on the stage?

To move the slide on the stage, we have to adjust the two "stage manipulator knobs" to reposition the slide one moves it left-right and the other  moves it up-down, closer to the center with the light. 

8. What two devices can be maneuvered to increase or decrease light intensity?

To increase or decrease the light intensity, we can maneuver the rheostat and/or iris diaphragm lever. 

9. What is the name of the highest magnifying objective?

The highest magnifying objective is called "oil immersion".

10. Which objective allows you to see the largest area of the object that you are viewing?

To view the largest area of the object, we have to use the scanning objective, the one with the magnification of 4x.  

Part 3

Functions of cells and organelles.

Procedure

1.  Pour 8 ounces tap water into each of two cups or glasses. Add 3 teaspoons salt to one of the cups and label it "Salt Water" with a piece of masking tape. Label the other cup "Fresh Water".
   
   
   
2.    Measure the length and greatest width of both pieces/carrots and record this measurement in Table 1 below.
   
   
   
   
   
3.    Tightly tie a piece of string around each carrot.
   
4.   Set one carrot/carrot piece down into the “Fresh Water” cup and the other down into the “Salt Water” cup.
   
5.  Take a photo of the two containers with their contents.
   
   
   
   
6.  Allow the carrots to sit in the cups for 24 hours.
7.  Ask yourself what will happen to both carrots in this experiment in terms of changes in length and diameter and why you think this will happen.  Record your predictions and rationale.

• I think that the carrot in the salt water solution will shrink slightly compared to the carrot in the fresh water. 
• Freshwater carrot will remain the same size because of the balanced concentration of the inside and the outside fluid. 

1. After 24 hours, remove the carrots and examine the tightness of the strings. Re-measure the carrots and record the findings in Table 1 below.

 Remove carrots from cups and take a photo next to each other outside of the containers.

 Record more observations.

a.       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.

b.      Observe which type of water caused a decrease in cell size.

c.       How did the actual results in the measurements compared to your predictions?

After taking it out of the water, the salt water carrot is visibly smaller and the string tied around it was loose. It also looks somewhat "wrinkled", or a better word would be shriveled. 
The salt water caused the carrot to decrease in its size. .
It looks like my prediction was true to the actual results. The carrot in the salt water did shrink and became smaller in size. 

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.

What is osmosis? Include these elements in your explanation:

Osmosis is the spontaneous net movement of solvent molecules through a semi-permeable membrane into a region of higher solute concentration, in the direction that tends to equalize the solute concentrations on the two sides. It may also be used to describe a physical process in which any solvent moves across a semipermeable membrane (permeable to the solvent, but not the solute) separating two solutions of different concentrations.

What is moving? Why?

When two different solutions have different molecular density concentrations, the diffusion occurs. 

The molecules with a higher concentration will be moving towards the area with the less concentration, to "balance" the solution's consistency. 

 What does not move? Why?

The molecules will not be moving if the concentration is neutral. Like adding water to water will "mix" the water molecules, but will not unbalance the total consistency.

 How is this important for the health of cells?

When cells encounter the undesirable substance (like a sodium), they will not only work very hard to maintain their inner balance but also will lose their intracellular fluid due to "overworking", which will result in the "shrinking" of the cell and in extreme cases, the complete destruction of it. (the cell will die)

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	2 inches	2 inches	.75 inch	.75 inch
Saltwater Carrot	2 inches	1.75 inch	.75 inch	.5 inch

Sources:

 "Function of Nucleolus." Function of Nucleolus. Web. 11 Sept. 2015.   <http://www.softschools.com/science/biology/function_of_nucleolus/>. 

Wikipedia. Wikimedia Foundation. Web. 14 Sept. 2015. 

<https://en.wikipedia.org/wiki/Osmosis>.