October 10, 2008

October 10, 2008
1. Optics concepts
a. Resolving power (R.P.): the minimum distance that 2 objects can be separated from each other and still be distinguished as 2 objects
i. RP microscope in class=0.2μm
ii. The smaller RP=stronger microscope (can see more detail)
b. Wavelength: how we see objects
i. Objects bounce off surfaces then people interpret patterns of bounced objects
ii. Different wavelengths of light give the object it’s color
iii. The smaller wavelength of light used, more detail we can see (RP smaller)
c. Refractive index: measure of how quickly light can move through a substance
i. Light moves at different speeds through different substances
ii. Refractive index of immersion oil is almost the same of glass
iii. Oil immersion has a less RP
2. Bright field microscopy
a. RP of best light microscope equal about 0.2 μm=200nm
b. RP of oil and glass are about the same
c. Need to stain bacteria b/c bacteria are so small that you wouldn’t be able to see them at all if they were not stained
d. Advantages
i. Can use stain techniques
ii. Can see shapes and size
e. Disadvantages
i. Hard to see very slender structures
ii. Can’t see how things move because you kill the bacteria
3. Dark field microscopy
a. Oblique light bounces off of objects in water, makes them “glow”
b. Advantages
i. Can watch movement of live microbes
ii. Can see very slender structures
c. Disadvantages
i. Loss of resolution (can’t see as much detail)
4. Electron microscopy
a. Why is the RP of an electron microscope so much smaller than that of a light microscope
b.Advantages & disadvantages of
c. Scanning electron microscopy (SEM)
d. Transmission electron microscopy (TEM)

Unsaturated Fat vs. Saturated fat?

Briefly discussing the differences between unsaturated and saturated fat in micro on Monday got me interested in the differences between the two. I found out that saturated fats are basically "the enemy" and unsaturated fats are "the good guys." To tell the differece between the two, saturated fats are hard at room temperature. Saturated fats are not essential to your health, and they come from animals and are commonly found in meat, eggs, and cheese. They are also far harder to digest and are full of cholesterol.

Unsaturated fats are liquid at room temperature and have been divided into two groups: Monounsaturated fats such as olive oil and polyunsaturated fats such as sunflower oil. Polyunsaturated fats are split into Omega 3 fatty acids and Omega 6 fatty acids. Monounsaturated fat (Omega 9) although not essential, is not harmful in moderation - a good quality (extra virgin first cold pressed) olive oil is a healthier alternative to the usual vegetable oil.

Kind of interesting!
-Kelsey Prosser

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