Atlas of plant and animal histology

Choose true or false. Each right answer scores 1, and each wrong answer scores -1. Not answered questions score 0.

1) Dyes are pigments that show affinity for some tissular components.

2) The part of the dye that provides the color is known as the chromogen.

3) Acid dyes stain the cell nuclei.

4) Metachromasia means that the color of the dye after the linking to the tissue is different from expected.

5) Hematoxylin-eosin is a general stain with only one dye.

6) Paraffin sections are stained before paraffin removal.

7) To stain resin-embedded sections, it is not necessary to remove the resin.

8) Ultrathin sections are contrasted with uranyl acetate.

9) Histochemical staining means that there is a chemical reaction involving some molecules of the tissue during the experimental technique.

10) The PAS staining method is intended to unveil the lipids of the tissues.

11) Enzymatic histochemistry uncovers some enzymes present in the tissues.

12) Enzymatic histochemistry can only be performed in fresh tissue.

13) Lectins are proteins that recognize some particular carbohydrates in a specific manner.

14) Lectins show autofluorescence and therefore can be observed directly with the fluorescence microscope.

15) Immunohistochemistry is based on antibodies to detect molecules in tissues.

16) Only proteins can be detected with immunohistochemsitry.

17) Polyclonal antibodies are able to recognize more than one part of a molecule.

18) In immunohistochemistry, the binding of the primary antibody to the specific molecule of the tissue cannot be visualized unless an enzyme is conjugated to the antibody.

19) Immunofluorescence allows the detection of more than one molecule at the same time.

20) For immunofluorescence, a particular type of antibody is used.

21) The immunofluorescence signal can be visualized as long as that of immunohistochemistry.

22) In situ hybridization is used to detect mRNA.

23) A probe is used in in situ hybridization to detect the same RNA sequence in all animal species.

24) To detect the hybridization of the probe and the RNA, antibodies have to be used to detect the modified nucleotide of the probe.

25) Cloning is a previous step for getting the probe for in situ hybridization.