Please submit the discussion and lab in the next 6 hours. You can submit the essay in 24 hours. Each section needs to be at least 500 words. I will post a rubric please follow it.
Discussion (do first)
Communicating health and science is really an important skill! If you are in the health field, you may have to explain complex information to the lay public. If you do not communicate well, you may not be able to truly understand their issue or they may not understand what they can do to improve their health. If you are going into science, you may also have to learn to take complicated scientific information so that the everyone can understand its importance.
This week, find and example of how science is communicated. This could be a show on National Geographic, BBC’s Earth, PBS’s Nature; a podcast such as NPR’s Science Friday, a book such as Rachel Carson’s Silent Spring , a TED talk or a show/program etc that you enjoy.
How has the author “hooked” you and captured your attention? What words did they use- complicated or more simplistic? What was the tone- comical, light, serious, etc? Who do you think is the intended audience? Did you understand what they were saying? How well did they explain science to you?
In your discussion, describe your article, book, show or podcast etc and share what you learned. Be sure to answer any questions or respond to comments in your forum and respond to 2 other postings. Post by Thursday and respond by Sunday. Be sure to cite your article.
Lab 2
In this activity we will look at tissue under virtual microscopes. Microscopes allow a person to magnify objects so that they can be examined in more detail. The compound light microscope is used for examining small or thinly sliced (horizontal) sections or longitudinal (lengthwise) sections of objects. Light microscopes can generally magnify objects a maximum of 1000 times, so that objects smaller than 200 nanometers (200 nanometers = 0.0000002 meters!) can’t be resolved well. To improve contrast, the microscopist uses stains or dyes that bind to cellular structures and absorb light. An electron microscope, on the other hand, can magnify objects that are 1000 times smaller than you can see using a light microscope, so that objects as small as 0.2 nanometers (0.2 nanometers = 0.0000000002 meters!) can be examined. To give you an example of how small 0.2 nanometers is: an average human female is approximately 1.6 meters, the diameter of a human eyeball is about 0.025 meters, a frog egg is approximately 0.001meters, and bacteria are about 0.000005 meters.

A cell is the basic, living, structural, and functional unit of the body. The diameter of human cells is approximately 0.00003 meters. Under a light microscope, you cannot see all the parts of a cell. However, you can see the plasma membrane of a cell, which encloses all cells and selects what substances can enter and exit the cell, and the nucleus, which contains the genetic material for the cell. Using an electron microscope allows a person to examine the internal structure of a cell in detail.
Although cells are highly organized, they do not function as isolated units in your body. They work together in groups called tissues. A tissue is a group of similar cells that function together to carry out specialized activities. For example, your skin is composed of multiple layers of cells that protect your body. Since all the cells are functioning together, your skin is a tissue. Also, since it is easy to scrape off the top layer of skin cells, this tissue is composed of multiple layers. Most organs are made up of different tissues, each with a different function within that tissue. For example, your heart is an organ composed of muscle tissue and nerve tissue that work together as a pump.
Identification of Microscope Components
1. The lens you look through is the eyepiece. The eyepiece magnifies an image by the factor indicated on the barrel of the eyepiece, usually 10X. If the factor is 10X, the image is magnified 10 times. Some microscopes have one eyepiece, others have two.
2. The revolving nosepiece is the turret-like circular mechanism that rotates so that different lenses can be selected. Always rotate the nosepiece by holding the outside of the revolving disk–never push on the lens barrels.
3. Each of the lens sets attached to the revolving nosepiece is an objective. As with the eyepiece, each objective is marked with its magnification factor. Microscopes may have any or all of the following objectives:
4X (scanning objective) is used for initial location of the specimen.
10X (low power objective) may also be used for initial location of the specimen. It is also used for observing specimens that do not need greater magnification.
40X (high-dry objective) is used for specimens requiring greater magnification.
100X (high-oil objective) is used for magnification of extremely small specimens, such as bacterial cells. The specimen must be immersed in oil, so the objective is called the high-oil objective.
4. Total magnification is determined by multiplying the power of the eyepiece by the power of the objective in use. Thus, when using a 10X eyepiece and the low power objective, total magnification is 100 (10 x 10=100).
5. The specimen is usually mounted on a glass or plastic microscope slide that rests on the stage, a platform just below the objective. The stage has a hole so that light can pass through the specimen from below.
6. Below the stage is a high-intensity lamp. Light rays from the lamp travel through the hole in the stage, through the specimen mounted on a slide, then through the objective and eyepiece, to the eye.
7. Sometimes the light from the lamp is too strong to see the specimen clearly. The light level may be reduced by adjusting the lamp intensity.
8. The entire upper assembly of the microscope is held in an upright position by a bar called the arm.The scope is supported by the base. The microscope should always be carried by holding on to the arm and the base.
9. The course-focus knobs and fine-focus knobs are on the arm. These knobs adjust the distance between the stage and objective, thus focusing an image of the specimen. The smaller fine-focus knob changes the distance very little, whereas the large coarse-focus knob changes the distance greatly. Always focus first with the coarse-focus knob while the objective is on the lowest power.
Procedure:
A. Go to: (Links to an external site.)
http://www.ncbionetwork.org/iet/microscope/ (Links to an external site.)
(Try copying and pasting the link in a new window if you are having trouble accessing the site.).
B. Click on the “Explore”. Click on the “?” on the slide box.
C. Click “Sample Slide”. The “Letter E”.
1. Use the Course focus at 4x to get the letter e in focus.
2. Use the “fine focus” to sharpen it.
3. Use the “Light Adjust” to change the light.
4. Change to 10x, 40x and 100x and observe what you can see.
5. Answer the questions below.
6. When you are done, click Close
D. Click Plant Slides and choose the onion root. Repeat steps 1-6 above. You can see that each cell in the onion root is in a different phase of cell division. We will learn more about this later.
E. Next, choose the bacteria slides. Repeat steps 1-6 above for the different stains: acid fast, endospore stain and gram stained bacteria.
F. Finally, click on “Human” . Choose at least 4 different slides. (There are 16 different human slides- you only have to look at 4. Feel free to explore the other slides, though. The cells are fascinating!). Repeat steps 1-6 above.
Questions:
1. Describe what you saw for each of the slides.
a. Letter e.
b. Onion root
c. Bacteria
d. Why is the letter e upside down?
2. What can you see in each of the above at 100x that you couldn’t see at 4x?
3. What are some organelles you can see? Of the slides above, which were you able to see the nucleus?
4. Describe the 4 different types of human cells. How are their sizes and shapes the same? How are they different?
5. Describe the function of the following organelles found in an animal cell:
a. Nucleus
b. Mitochondria
c. Endoplasmic reticulum
d. Golgi
e. ribosome
Essay
1. Describe the structure and function of each of the following parts of the cell. (10 points)
a. Nucleus
b. Ribosome
c. Endoplasmic Reticulum
d. Golgi
e. Lysosome
f. Cytoskeleton
g. Cilia
h. Mitochondria
i. Chloroplast
j. peroxisome
2. Describe the structure of the cell membrane. Include:
a. the structure of the phospholipid bilayer
b. the role of unsaturated fatty acids
c. the role of cholesterol
d. the function of proteins on the membrane
e. the function on membrane rafts
3. Describe the role of each of the following in membrane transport (10 points)
a. Facilitative diffusion
b. Osmosis
c. Active transport
d. Endocytosis
e. Exocytosis
4. How does saturated and unsaturated lipids affect the fluidity of membranes? What is the role of cholesterol? (5 points)
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