Case Study #2 - Cassie is desperate to lose 20 pounds

Human Biol

CELL / MICROSCOPE LAB: (4 pages total)

This case study may require you to deep a little deeper. I have added a video on cellular respiration which takes place in the mitochondria. Some extra information: one pound is roughly 3500 calories and the average adult eats about 2000 calories a day.

Case Study #2

Cassie is desperate to lose 20 pounds that she gained during her first two years of college. She has tried adding some exercise to her routine and eating better, but she has not seen
any dramatic change in her weight. Having read so many advertisements for weight-loss supplements, she feels compelled to purchase one that claims that she can lose up to
10 pounds of fat in the first week. The product seems easy enough to use—just take it
twice a day and Cassie won’t have to restrict her diet or exercise.

·  What questions should Cassie be asking before she decides to take this product?

·  Given your knowledge of cellular respiration, would it be possible for Cassie to lose
10 pounds of fat in one week? Explain.

·  Are there any possible concerns Cassie should have about taking this product?

 

Using the following site

https://biology.arizona.edu/cell_bio/activities/cell_cycle/cell_cycle.html

 

Complete the onion root tip activity and record your results in the provided chart below. Then answer the questions below.

 

            Interphase       Prophase          Metaphase       Anaphase        Telophase        Total

Number of cells                                                                       36

Precent of cells                                                                        100%

 

 

1. Why are there so many cells in prophase?

 

2. What phase are these cells in?

 

a.           b.         c.         d. 

 

If we were in the lab you would make a slide of your own cheek cells. Here are the steps you would follow:

 

Procedure:

1. Put a drop of methylene blue on a slide. Caution: methylene blue will stain clothes and skin.

2. Gently scrape the inside of your cheek with the flat side of a toothpick. Scrape lightly.

3. Stir the end of the toothpick in the stain and throw the toothpick away.

4. Place a coverslip onto the slide

 

This is what it would look like

 

3. What are the dark areas in each cell?

 

4. What organelles are only found in plant cells? Why are these not found in animal cells?

 

 

 

The most familiar type of microscope is the standard light microscope. The base (L) and arm (G) are usually one single piece of cast metal. The arm is the correct place to grip the microscope when carrying it while supporting the base with the palm of your other hand. Color the arm black and the base red. The stage (I) is the platform that supports the specimen to be observed. The stage has a hole in its center to allow light to pass through, so specimens must be supported on a microscope slide. Color the stage blue. You can control how much light goes through the specimen by adjusting the diaphragm (K). It has a range of 1 to 5, with 5 being the most light. Color the diaphragm green. Since any slight movement of the specimen is magnified many times, the slide is usually held down by a pair of stage clips (J). Color the stage clips gray.

Light microscopes use either a bulb or a mirror (M) as their light source. Never use direct sunlight; it may damage your eyes. Color the light source yellow.

After the light has passed through the specimen, it enters the objective lens (often called "objective" for short). The shortest of the three objectives is the scanning-power objective lens (N), and has a power of 4X. Leave the 4X objective white. The second objective is the low-power objective (F), which is almost always made to produce a magnification of 10 times (10X). Put polka dots on the low-power objective. The high-power objective lens (H) has a magnification of 40X. Draw stripes on the high-power objective.

The body tube (C) allows the light from the objective to pass upward to form the first magnified image; that image is further magnified by the eyepiece or ocular (A). The eyepiece is usually 10X. Color the body tube brown. Color the ocular lens orange.

The total magnification obtained is the product of the eyepiece times that of the objective lens. You can easily switch objectives by turning the rotating nosepiece (E). Color the nosepiece blue-green.

The coarse adjustment knob (B) is the larger on your microscope. You will use this primarily to focus on your specimen. DO NOT USE THE COARSE ADJUSTMENT KNOB ON HIGH POWER (40X), it will crack your slide. Color this knob pink. The fine adjustment knob (D) is also for minute focusing. You use this after you have focused with the coarse adjustment knob. Color this knob tan.

QUESTIONS:

1. Which two structures on the microscope will you use to focus on your specimen?

2. Why should you never use the coarse adjustment knob on high power?

3. Our microscopes have three objectives. What are their powers?

4. What is the magnification of the ocular lens?

5. What is the shortest objective called?

6. Which structure controls how much light passes through the specimen?

7. You should carry the microscope by placing your palm on the _____________________ and gripping the ___________________ with your other hand.

You will need to submit the answers to the above 7 questions and label letters A-N on the following page.