quiz pool #7 Flashcards
Which is longer, the excitation wavelength or the emission wavelength? Why?
The emission wavelength is longer and thus less energy. This is because a molecule cannot give off more energy than it absorbed.
What does DAPI bind to? What color is it?
Binds to double stranded DNA; color is blue
What organelle would you expect DAPI to stain?
Chromosomes
. Name the colors of the visible spectrum from longest wavelength to shortest.
Red Orange Yellow Green Blue Violet
What is the range of wavelengths in the visible spectrum? Be sure to include units!
red(700), orange(647), yellow (586), green(535), blue(492), violet (422-400)=wavelength nm=nanometer
Name 2 dyes that stain mitochondria
- MitoTracker
2. Rhodamine 123
How is the excitation wavelength prevented from reaching your eyes in a fluorescence microscope?
The dichroic mirror has a special property where it can reflect light with short wavelengths, but allow longer wavelengths to pass through. The emission wavelength is longer than the excitation wavelength and therefore, the emission wavelength will be able to pass through the objective lens whereas the excitation wavelength would have been reflected.
The mercury lamp emits white light, yet colored light emerges from the objective lens. Why?
white light passes through an excitation filter that passes some wavelengths and then hits the dichroic mirror which has the unusual property of reflecting light w short wavelengths(blue) and allow longer wavelengths (green) to pass through
What does the word “dichroic” mean? Why is it used to describe the mirror that acts as a beam splitter?
Dichroic refers to any optical device which can split a beam of light into two beams with differing wavelengths. The mirror is called this because one beam of light will reflect off the surface of the dichroic mirror into the objective and another will pass through the dichroic to the eyepiece. (dichromatic or beam splitter)
If you use a fluorescent dye that is excited by a green wavelength, would you expect it to emit in the red or the blue?
red
Name 2 types of cells you will be looking at today.
Ø Buccal (cheek) cells
Ø Cultured Chick Fibroblasts
Ø Slide of Small Intestines
What is a lectin? What does it bind to?
lectins such as wheat ger, agglutinin and concanavalin A which are proteins that bind to specific sugar residues of glycoproteins
What is a glycoprotein?
proteins w oligosaccharides or sugar residues attached
To which amino acids can sugars be attached?
asparagine, serine, threonine, hydroxylsine, hydroxyproline
