Ap Bio Exercise 4 Lab Answers

Exercise 4 Lab Report

(3) Individual: Prepared blood slide

(a.) Compare red and white blood cells - what cellular features are present in white cells but not in red blood cells and vice versa? Include a digital image of the blood cells present in the permanent dry.

Red Blood cells carry hemoglobin inside of them which helps carry oxygen from the lungs to the rest of the body. Hemoglobin is what gives blood cells the red pigmentation. The amount of blood cells present in the blood give it the red color it has. White blood cells, on the other hand, are few in number and create antibodies to fight against infections. Moreover, the two are also different in their structure as red blood cells are circular and white blood cells tend to
Which is more prevalent in a typical blood sample? How much more prevalent? Why might this be based on the specialized function of each?

Red blood cells were more prevalent than white blood cells. In a field of view of about a thousand blood cells, there were about only three white blood cells in comparison to the colonies of red blood cells (1000:3.) Based on this, red blood cells are necessary because they are able to regulate processes that keep us in equilibrium. We require more of them in order to help oxygen circulate through the body and carry nutrients. We need white blood cells to help fight infection, but we don’t require too many. Our homeostasis and proper body functioning is dependent on the red blood cells. (c.) The Human Blood Smear prepared permanent mount was fixed and permeabilized with methanol only and stained the differential dye Wright-Giemsa solution (a mixture of methylene blue, eosin Y, and Azure B). Compare this to the slides (stained, unstained) of your cheek cells you prepared. In your answer, consider the effect/purpose of the active reagents in the fixative, the permeabilization solution, and stains (methylene blue, DAPI, Texas Red). For example, why are the “fix” and “permeabilize” steps needed when using a reagent like Texas-Red®-phalloidin, whereas they are not with a dye like methylene blue or Wright-Giemsa? (Hint - look up on pubchem or elsewhere the
The excitation wavelength you would use to see the red fluorescence from PI would be around 480 to 570 nm. Propidium Iodide is considered to be autofluorescence in Texas-Red with chlorophyll at about 480 to 570 nm. The excitation/emission of Propidium Iodide is similar to chlorophyll and that of Texas-Red fluorochrome because they all fluoresce red.

(e.) Concluding remarks section of the review paper by Giepmans (2008):
“Exaggeratedly stated, with fluorescence microscopy, you almost see nothing, i.e., only your fluorescent signal(s); with EM, you see everything, i.e., organelles, macromolecules and membranes.

Apply this statement to the use of fluorescent dyes like DAPI versus non-specific contrast stains like methylene blue used in brightfield. Give specific reference to your results and figures (sketches, digital images, etc.). Describe at least two disadvantages of the use of fluorochromes over simple contrast