chapter 1 (methods)

Question 1

fixation

Answer 1

process by which specimen is treated by exposing it to a fixative in order to preserve tissue permanetently
-the fixative should be 15-20 times more in volume than the specimen (samples must be frozen they can not be left out) (fixative fixes it/freezes it)
-fixative is choosen based on the type of molecule you want to preserve

Question 2

purpose of fixation

Answer 2

prevent autolysis and bacterial attack, allow clear staining of sections, leave them as close to their living state as possible, happens because of the reaction between the fixative and the protein which forms a gel (keeps in in vivo)

Question 3

histotechnology

Answer 3

science is centering on the microscopic detection of tissue abnormalities for disease diagnosis, treatment, etc…(can also prep surgical specimen for screening by pathologist.)

Question 4

sample size

Answer 4

thinner better because then the light can pass through it easier, but not too thin

Question 5

histology

Answer 5

microscopic anatomy; study biological tissue includes histopathy (microscopic study of diseased tissue)

Question 6

resolving power

Answer 6

limit of resolution of a microscope is the smallest distance between 2 points that can be seen using a scope

Question 7

hematoxolin and eosin

Answer 7

most common stains

Question 8

transmission electron microscopy

Answer 8

high magnification of cross section (tungsten filament, condenser lens, specimen, objective lens, projector lens, imaage on screen)
-black and white
-sends x ray through the tissue

Question 9

scanning electron microscopy

Answer 9

lower magnification of surfaces
-black and white
-only scans the surface of the tissue

Question 10

confocal fluorescence

Answer 10

clearer image of single cell
-in color (better)

Question 11

conventional fluorescence

Answer 11

blurry image of cell
-in color

Question 12

cell culture concerns

Answer 12

contamination is a major concern

Question 13

cultures

Answer 13

-can be plant or animal
-grow hela cells or plants or clone mice hearts etc.

Question 14

microtomes

Answer 14

used to cut samples in prep for slides

Question 15

cryostat

Answer 15

used to freeze the tissue, section tissue without going through all the other steps that could damage the sample BUT your CAN NOT save the sample it is NOT viable for life like fixation
-used in hospitals for quick diagnosis, takes less time
-takes no time to put it through the paraffin

Question 16

histochemisty

Answer 16

the study of chemical grouping within the cell and tissues

Question 17

Feulgen Stain

Answer 17

feulgen nuclear reaction for the specific staining of DNA in cytohistochemical samples
-it is a chemical treatment, HCL hydrolysis to produce free aldehyde groups in the DNA backbone structure that could be detected by a colored reaction for aldehydes
-stain for DNA used to be the only way to look for DNA, new methods use antibodies

Question 18

MAB

Answer 18

antibody drug/ biologic
-NOT A CHEMICAL DRUG

Question 19

indirect immunohistochemistry

Answer 19

uses primary antibody, labelled secondary antibody to target proteins

Question 20

immunoflourescence

Answer 20

-develop antibody against antigen
-hit it w a lazer get a color reaction
-labeled primary antibody onto protein with a flourescant tag and signal
-antibodies make the color

Question 21

antibodies

Answer 21

can be made against anything, DNA, Proteins, etc and the antibody will NOT bind to anything else

Question 22

colormetric

Answer 22

preferred by pathologist
-takes less time and easier to work with than flourescence
-lasts forever and you can go back tot he sample whenever
-flourescence will not last forever (the signals die)

Question 23

autoradiography

Answer 23

an image on an x-ray film or nuclear emulsiom produced by the pattern of decay emissions (beta particles or gamma rays) from a distrubutor of radioactive substance
-not used as much as radioactive isotopes or antibodies w flourescent tags
-requires microscope film (makes it harder)

Question 24

In Situ hybridization

Answer 24

uses single strand DNA instead of antibody
-DNA or RNA has a tag that joins DNA in target site

Question 25

xray crystallography

Answer 25

x ray beam hits crystalized DNA molecules and its reflected onto the film (the pattern that Watson and crick saw)

Question 26

eye tissue

Answer 26

the most difficult tissue to cross section bc it is fragile and has different types of tissues within it
-need a different fixative per tissue (lens, cornea etc.)
-davidson is the best fixative

Question 27

photomicroscopy

Answer 27

camera attachment to microscope

Question 28

many different types of DNA

Answer 28

-b DNA (regular)
-Z DNA
-Queadraplex etc…