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Markers used to visualize antigen-antibody bindings in IHC include: A) Fluorescent dyes and enzymes B) Radioactive elements C) Colloidal gold D) All of the above

Immunohistochemistry (IHC) relies on the specific interaction between : A) Acidic dyes and basic proteins B) Antigens in tissue sections and labeled antibodies C) Paraffin wax and xylene D) Enzymes and lipid membranes

Living cells can be examined in vitro using which microscopic technique? A) Phase-contrast light microscopy B) Standard paraffin sectioning C) Electron microscopy under high vacuum D) Dry slide mounting

What is a common disadvantage shared by both Celloidin and Frozen section techniques? A) Inability to yield serial sections B) Destruction of all tissue lipids C) Total inability to stain cells D) Requirement of high heat during embedding Answer

Which machine is used to cut frozen tissue sections? A) Standard microtome B) Cryostat C) Centrifuge D) Autoclave

Enzyme histochemistry requires unfixed or mildly fixed tissue cut on a cryostat to avoid: A) Excessive tissue shrinkage B) Destruction of enzyme activity by heat and organic solvents C) Over-staining by hematoxylin D) Artifacts like tissue folding

Lipid/fat contents in frozen sections are highlighted in orange by using: A) Hematoxylin B) Sudan III C) Toluidine blue D) Silver stain

Brilliant crystal blue is used to stain reticulocytes (immature RBCs) outside the living body. This is an example of: A) Vital stain B) Supravital stain C) Histochemical stain D) Counterstain

Trypan blue and Indian ink are examples of which type of staining? A) Vital staining B) Supravital staining C) Metachromatic staining D) Immunohistochemical staining

Differential staining of blood cells (such as Giemsa and Leishman stains) utilizes: A) Vital stains B) Neutral stains C) Enzyme histochemical stains D) Cryosections

Which stain colours Golgi apparatus and nerve fibers brown, and reticular fibers black? A) Sudan III B) Silver (Ag) stain C) Orcein stain D) Neutral stain

Eosin gives a pinkish tint to basic cellular components. Which of the following is stained by Eosin? A) Cell nucleus B) Rough Endoplasmic Reticulum (RER) C) Cytoplasm, mitochondria, and muscle fibers D) DNA and RNA Answer: C

Hematoxylin is classified as a basic dye. Which cell components does it preferentially stain? A) Cytoplasm and mitochondria B) Acidic components such as the nucleus and RER C) Collagen fibers and fat droplets D) Cell membrane carbohydrates only

Paraffin sectioning is performed using an instrument called a: A) Cryostat B) Centrifuge C) Microtome D) Spectrophotometer

Which of the following chemicals is commonly used as a clearing agent? A) Formalin B) Xylene C) Hematoxylin D) Toluidine blue

Which process is required for hard tissues like bone and tooth before they undergo dehydration? A) Infiltration B) Decalcification C) Trimming D) Metachromasia

Dehydration of tissue sections is achieved by transferring the tissue through increasing concentrations of alcohol up to: A) 50% B) 70% C) 95% D) 100%

Which step in paraffin preparation involves replacing alcohol with a paraffin solvent like xylene? A) Fixation B) Dehydration C) Clearing D) Embedding

In H&E stain, Eosin acts as an acidic dye (-) that colors acidophilic structures bright pink. Which of the following is Acidophilic? a) Cell nucleus b) Ribosomes (RNA) c) Mitochondria and Collagen d) DNA molecules

Which stage of paraffin technique involves replacing alcohol with organic solvents to make the tissue translucent? a) Fixation b) Dehydration c) Clearing d) Infiltration